CN118486334A - Multi-layer load bar flexure for magnetic storage device - Google Patents

Abstract

A suspension assembly for a magnetic storage device. The suspension assembly includes a base plate, a load bar, and a flexure. The hinge of the load bar is configured to flex such that the distal portion of the load bar moves relative to the base plate. The flexure includes a hinge portion and a fixed portion adjacent to the hinge portion. Each of the fixed portions of the flexure includes a first layer and a second layer. The first layer is interposed between the second layer and the load bar. The hinge portion of the flexure includes the second layer, but does not include the first layer. The thickness of the second layer of the hinge portion of the flexure is less than the thickness of the second layer of the stationary portion of the flexure.

Description

Multi-layer load bar flexure for magnetic storage device

Technical Field

The present disclosure relates generally to magnetic storage devices and, more particularly, to multi-layer load bar flexures for magnetic storage devices.

Background

Magnetic storage devices, such as hard disk drives ("HDDs"), are widely used to store digital data or electronic information for enterprise data processing systems, computer workstations, portable computing devices, digital audio players, digital video players, and the like. Typically, HDDs include a read/write head that helps facilitate data storage on the disk. Each read-write head is supported on a suspension assembly. Some HDDs include a suspension assembly having a flexure.

Disclosure of Invention

There is a need for a magnetic storage device and method of manufacture that reduces variations in the spacing between a read-write head of a suspension assembly of the magnetic storage device and a disk from which the read-write head reads data or writes data to the disk. The subject matter of the present application has been developed in response to the present state of magnetic memory devices, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available magnetic memory devices, such as those discussed above. Accordingly, examples of the present disclosure overcome at least some of the disadvantages of the prior art.

The following is a non-exhaustive list of examples that may or may not be claimed of the subject matter disclosed herein.

A suspension assembly for a magnetic storage device is disclosed herein. The suspension assembly has a base plate and a load bar attached to the base plate. The load bar includes a distal portion and a hinge. The hinge is interposed between the distal portion and the base plate and is configured to flex such that the distal portion moves relative to the base plate. The suspension assembly includes a flexure attached to and movable with a base plate and a load bar. The flexure has a hinge portion that spans a hinge of a load bar and a fixed portion adjacent to the hinge portion. Each of the fixed portions of the flexure has a first layer and a second layer. The first layer is interposed between the second layer and the load bar. The hinge portion of the flexure includes a second layer but not a first layer such that a gap is defined between the first layers of the fixed portion of the flexure that spans the hinge. The thickness of the second layer of the hinge portion of the flexure is less than the thickness of the second layer of the stationary portion of the flexure. The foregoing subject matter of this paragraph characterizes example 1 of the present disclosure.

The ratio of the thickness of the first portion of the second layer to the thickness of the second portion of the second layer is greater than 1 and no more than 2.4. The foregoing subject matter of this paragraph characterizes example 2 of the present disclosure, wherein example 2 further comprises the subject matter according to example 1 above.

The load bar is made of a metallic material. The foregoing subject matter of this paragraph characterizes example 3 of the present disclosure, wherein example 3 further comprises the subject matter according to any one of examples 1 to 2 above.

The first layer is made of a metallic material. The foregoing subject matter of this paragraph characterizes example 4 of the present disclosure, wherein example 4 further comprises the subject matter according to any one of examples 1 to 3 above.

The first layer is positioned directly above the load bar. The foregoing subject matter of this paragraph characterizes example 4 of the present disclosure, wherein example 5 further comprises the subject matter according to any one of examples 1-4 above.

Each of the fixed portions of the flexure has a third layer. The foregoing subject matter of this paragraph characterizes example 4 of the present disclosure, wherein example 6 further comprises the subject matter according to any one of examples 1-5 above.

The second layer is interposed between the first layer and the third layer. The foregoing subject matter of this paragraph characterizes example 7 of the present disclosure, wherein example 7 further comprises the subject matter according to example 6 above.

The third layer has a substantially uniform thickness. The foregoing subject matter of this paragraph characterizes example 8 of the present disclosure, wherein example 8 further comprises the subject matter according to any one of examples 6-7 above.

The third layer is made of copper. The foregoing subject matter of this paragraph characterizes example 9 of the present disclosure, wherein example 9 further comprises the subject matter according to any one of examples 6-8 above.

The first, second and third layers are arranged in a stack. The foregoing subject matter of this paragraph characterizes example 10 of the present disclosure, wherein example 10 further comprises the subject matter according to any one of examples 6-9 above.

The second layer is made of a photosensitive polyimide material. The foregoing subject matter of this paragraph characterizes example 11 of the present disclosure, wherein example 11 further comprises the subject matter according to any one of examples 1 to 10 above.

The second layer is made of a dielectric material. The foregoing subject matter of this paragraph characterizes example 12 of the present disclosure, wherein example 12 further comprises the subject matter according to any one of examples 1-11 above.

Disclosed herein is a magnetic memory system. The magnetic storage system includes a base plate, a number of platters, and a carrier arm. The bracket arm includes a load bar attached to a base plate. The load bar includes a distal portion, a hinge, and a flexure. The hinge is interposed between the distal portion and the base plate and is configured to flex such that the distal portion moves relative to the base plate. The flexure is attached to and movable with the base plate and the load bar. The flexure includes a hinge portion that spans a hinge of a load bar and a fixed portion adjacent to the hinge portion. Each of the fixed portions of the flexure includes a first layer and a second layer. The first layer is interposed between the second layer and the load bar. The hinge portion of the flexure includes a second layer but not a first layer such that a gap is defined between the first layers of the fixed portion of the flexure that spans the hinge. The thickness of the second layer of the hinge portion of the flexure is less than the thickness of the second layer of the stationary portion of the flexure. The foregoing subject matter of this paragraph characterizes example 13 of the present disclosure.

The ratio of the thickness of the first portion of the second layer to the thickness of the second portion of the second layer is greater than 1 and no more than 2.4. The foregoing subject matter of this paragraph characterizes example 14 of the present disclosure, wherein example 14 further comprises the subject matter according to example 13 above.

The hinge is biased toward a surface of at least one of the number of optical discs to allow a head of the distal portion to read data from or write data to the at least one optical disc. The foregoing subject matter of this paragraph characterizes example 15 of the present disclosure, wherein example 15 further comprises the subject matter according to any one of examples 13 to 14 above.

Also disclosed herein is a method of manufacturing a suspension assembly for a magnetic storage device. The method includes forming a second layer over the first layer. The method also includes applying a mask to the second layer. The translucency of the first portion of the mask is different from the translucency of the second portion of the mask. The method also includes illuminating light through the first and second portions of the mask. The method also includes removing the mask from the second layer and etching the second layer such that a first portion of the second layer to which the first portion of the mask is applied has a first thickness and a second portion of the second layer to which the second portion of the mask is applied has a second thickness, wherein the second thickness is less than the first thickness. The foregoing subject matter of this paragraph characterizes example 16 of the present disclosure.

Disclosed herein is a method of manufacturing a suspension assembly for a magnetic storage device. The method includes forming a third layer on the second layer by etching at least a portion of the fourth layer after forming the fourth layer over the second layer and forming the fifth layer under the first layer. The method also includes removing the fourth and fifth layers by chemical cleaning, forming a sixth layer over the third layer, forming a seventh layer under the first layer, and removing a portion of the first layer and a portion of the seventh layer. Each removed portion is aligned with a second portion of the mask. The method also includes removing the sixth layer and the seventh layer. The foregoing subject matter of this paragraph characterizes example 17 of the present disclosure, wherein example 17 further comprises the subject matter according to example 16 above.

A portion of the mask comprises a halftone glass mask. The foregoing subject matter of this paragraph characterizes example 18 of the present disclosure, wherein example 18 further comprises subject matter according to any of examples 16-17 above.

The first layer is made of stainless steel. The second layer is made of a polyimide material. The third layer is made of copper. Each of the fourth layer, the fifth layer, the sixth layer, and the seventh layer is made of a dry film photoresist. The foregoing subject matter of this paragraph characterizes example 19 of the present disclosure, wherein example 19 further comprises the subject matter according to any one of examples 16-18 above.

A method of manufacturing a suspension assembly of a magnetic storage device includes attaching a flexure to a base plate and a load bar such that a second portion of a second layer spans a hinge portion of the load bar. The foregoing subject matter of this paragraph characterizes example 20 of the present disclosure, wherein example 20 further comprises subject matter according to any one of examples 16-19 above.

The described features, structures, advantages, and/or characteristics of the subject matter of the present disclosure may be combined in any suitable manner in one or more examples and/or embodiments. In the following description, numerous specific details are provided to give a thorough understanding of examples of the presently disclosed subject matter. One skilled in the relevant art will recognize that the subject matter of the present disclosure may be practiced without one or more of the specific features, details, components, materials, and/or methods of the specific examples or embodiments. In other instances, additional features and advantages may be recognized in certain examples and/or implementations that may not be present in all examples or implementations. In addition, in some instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the disclosed subject matter. The features and advantages of the subject matter of the present disclosure will become more fully apparent from the following description and appended claims, or may be learned by the practice of the subject matter as set forth hereinafter.

Drawings

In order that the advantages of the disclosure will be readily understood, a more particular description of the disclosure briefly described above will be rendered by reference to specific examples that are illustrated in the appended drawings. Understanding that these drawings depict only typical examples of the disclosure and are not therefore to be considered to be limiting of its scope, the subject matter of the application will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 is a schematic perspective view of a magnetic storage device according to one or more examples of the present disclosure;

FIG. 2 is a schematic bottom plan view of a suspension assembly of a magnetic storage device according to one or more examples of the present disclosure;

FIG. 3 is a flow chart of a method of manufacturing a suspension assembly of a magnetic storage device according to one or more examples of the present disclosure;

FIGS. 4A-4O are schematic cross-sectional side elevation views of a suspension assembly of a magnetic storage device at various stages of manufacturing a multi-layer flexure of the suspension assembly of the magnetic storage device, in accordance with one or more examples of the present disclosure;

FIG. 5A is a schematic cross-sectional side elevation view of a suspension assembly of a magnetic storage device according to one or more examples of the present disclosure; and is also provided with

FIG. 5B is a schematic cross-sectional side elevational view of the suspension assembly of FIG. 5A having a load bar and flexure bent about a hinge.

Detailed Description

Reference throughout this specification to "one example," "an example," or similar language means that a particular feature, structure, or characteristic described in connection with the example is included in at least one example of the present disclosure. Throughout this specification, the appearances of the phrases "in one example," "in an example," and similar language may, but do not necessarily, all refer to the same example. Similarly, use of the term "an embodiment" means an embodiment having a particular feature, structure, or characteristic described in connection with one or more examples of the present disclosure, however, an embodiment may be associated with one or more examples if no explicit correlation is indicated.

Referring to FIG. 1, a magnetic storage device 100 according to one example is depicted as a Hard Disk Drive (HDD). However, in other examples, the magnetic storage device 100 may be any of a variety of magnetic storage devices without departing from the spirit of the subject matter of the present disclosure. The magnetic storage device 100 includes a housing 102 that seals or encloses an interior cavity 114 defined within the housing. The housing 102 includes a base 130 and a cover 132 (shown in phantom to avoid obscuring internal features of the magnetic storage device 100 within the interior cavity 114 of the housing 102). A cover 132 is coupled to the base 130 to enclose the interior cavity 114 from the environment outside the housing 102. In some embodiments, a seal or gasket is positioned between the base 130 and the cover 132 to facilitate a seal between the base 130 and the cover 132. In some examples, the substrate 130 is made of a metallic material, such as stainless steel.

The magnetic storage device 100 includes various features located within the interior cavity 114 of the housing 102. In some examples, the magnetic storage device 100 includes a carrier 103, a platter 115, a spindle motor 121, and a Voice Coil Motor (VCM) 125 within the cavity 114. The carrier 103 includes a head stack assembly 107 that includes a plurality of carrier arms 105 and at least one head gimbal assembly 109 (e.g., a suspension) coupled to a distal tip of each carrier arm of the plurality of carrier arms 105. Each head gimbal assembly 109 includes a suspension assembly 135 and a slider 142. The slider 142 includes at least one read/write head coupled to the slider 142 (e.g., embedded in the slider). Although the magnetic storage device 100 in fig. 1 is shown with five carrier arms 105 and four platters 115, in other examples, the magnetic storage device 100 may have fewer or more than five carrier arms 105, or fewer or more than four platters 115. In one example, each side of each carrier arm 105 facing the disk 115 has a head gimbal assembly 109 (e.g., each of the bottom and top carrier arms 105 may have one head gimbal assembly 109 and each of the intermediate carrier arms 105 between the bottom and top carrier arms 105 may have two head gimbal assemblies 109). Similarly, although magnetic storage device 100 is shown with one spindle motor 121 and one VCM 125, in other examples, magnetic storage device 100 may have any number of spindle motors 121 and VCM 125.

The spindle motor 121 is coupled to a base 130. In general, the spindle motor 121 includes a fixed portion immovably fixed with respect to the base 130, and a spindle rotatable with respect to the fixed portion and the base 130. Accordingly, the spindle of the spindle motor 121 may be considered part of or integral with the spindle motor. In general, the spindle motor 121 may be used to rotate a spindle relative to the base 130. The disks 115 or disks are co-rotatably fixed to the spindle of the spindle motor 121 via respective hubs 122, which are co-rotatably fixed to the respective disks 115 and spindle. When the spindle of the spindle motor 121 rotates, the disk 115 rotates accordingly. In this way, the spindle of the spindle motor 121 defines the rotational axis of each disk 115. The spindle motor 121 is operatively controlled to rotate the disk 115 a controlled amount in the direction of rotation 190 at a controlled rate.

Each of the disks 115 may be any of various types of magnetic recording media. Generally, in one example, each disk 115 includes a substrate and a magnetic material applied directly or indirectly to the substrate. For example, the magnetic material of disk 115 may be a conventional granular magnetic recording disk or wafer having a magnetic layer with a plurality of magnetic grains on each bit. In granular magnetic media, all bits are coplanar and the surface 116 of the disk is substantially smooth and continuous. In one example, each bit has a magnetic dipole moment that may have an in-plane (longitudinal) orientation or an out-of-plane (perpendicular) orientation.

When the disk 115 is rotated in the read-write mode, the VCM 125 electromagnetically engages the voice coil of the carrier arm 105 to rotate the carrier arm 105 and the head gimbal assembly 109 coupled to the carrier arm 105 relative to the disk 115 in a rotational direction along a plane parallel to the read-write surface 155 of the disk 115. The carrier arm 105 is rotatable to position the read/write head of the head gimbal assembly 109 over a designated radial area of the read/write surface 155 of the corresponding disk 115 for reading and/or writing operations. VCM 125 is secured to base 130 in engagement with the voice coil of carrier arm 105, which is rotatably coupled to base 130 via spindle 127 extending through carrier 103. Typically, spindle 127 defines an axis of rotation about which carrier arm 105 rotates when actuated by VCM 125.

The bracket arms 105 are non-movably secured to a base of the bracket 103 (e.g., integrally formed as a one-piece body with the base) and extend away from the base in a spaced apart manner relative to one another. In some embodiments, the bracket arms 105 are equidistantly spaced from one another and extend parallel to one another. A respective one of the disks 115 is positioned between adjacent carrier arms 105. In idle mode (e.g., when no read or write operations are being performed), VCM 125 is actuated to rotate carrier arm 105 in a radially outward direction relative to disk 15 such that head gimbal assembly 109 is parked or unloaded onto ramp support 117, which is secured to substrate 130.

Each read/write head of the slider 142 contains at least one read transducer and at least one write transducer. The read transducer is configured to detect a magnetic characteristic (e.g., magnetic bit pattern) of the platter 115 and convert the magnetic characteristic to an electrical signal. In contrast, the write transducer changes the magnetic properties of the disk 115 in response to the electrical signal. For each head gimbal assembly 109, electrical signals are transmitted to and from the read/write head via electrical traces or wires 198 formed in the slider 142 and flexure 140 or coupled to the slider 142 and flexure 140 (see, e.g., FIG. 1). The electrical traces of the slider 142 and flexure 140 are electrically interconnected to facilitate the transmission of electrical signals between the read/write head and the flexure connector 104 of the magnetic storage device 100, which communicates with the control module of the magnetic storage device 100 (see, e.g., FIG. 1). The control module is configured to process the electrical signals and facilitate the transfer of the electrical signals between the magnetic storage device 100 and one or more external computing devices. Typically, the control module includes software, firmware, and/or hardware for controlling the operation of the various components of the magnetic storage device 100. The control module may include a printed circuit board on or in which hardware is mounted. Solder joints are utilized to electrically connect corresponding electrical contact pads (and corresponding electrical traces) of the slider 142 and flexure 140.

Although not shown, in some implementations, the head gimbal assembly 109 also includes a head actuator that is selectively operable to move the read/write head relative to the hinge portion 140B of the flexure 140.

Fig. 2 is an underside view of a suspension assembly 135 of a magnetic storage device 100 according to one or more examples of the present disclosure. In some examples of the present disclosure, suspension assembly 135 includes a base plate 192 and a load bar 196 having a distal end 133, the lower sides of which are shown in fig. 2. The bottom plate 192 spans between and couples together the distal ends 133 of the bracket arms 105 and the distal ends 133 of the load bars 196. The load bar 196 is coupled to the base plate 192 of the suspension assembly 135 via the hinge 141 of the load bar 196 and flexes relative to the base plate. In some examples, the hinge 141 includes two hinges on either side of the gap 199 in the load bar 196. The hinge 141 biases the load bar 196 toward the surface 116 of at least one of the number of disks 115 to allow the read/write head 134 of the distal portion 133 of the carrier arm 105 to read data from and/or write data to at least one of the number of disks 115. In some examples, head 134 floats above surface 116.

In some examples, load bar 196 is made of a metallic material. When flexed, hinge 141 acts as a spring to create a force (referred to herein as a "gram load") to move head 134 of load bar 196 toward surface 116 into a position such that the fly height between surface 116 and head 134 is minimized. This is achieved, for example, by means of pressurized air. The gap between head 134 and disk 115 may be referred to herein as the "fly height" or "fly height". In general, it is preferable to minimize this gap and/or stabilize it to maximize the signal quality of the data transferred between disk 115 and read-write head 134. In some examples, the flying height is approximately equal to or less than five nanometers ("nm"). However, examples of the present disclosure are not limited thereto.

The suspension assembly 135 also includes a flexure 140 that extends along the underside of the base plate 192 and load bar 196. The flexure 140 includes a portion 140B that extends over (e.g., transverse to) the hinge 141. Examples of the present disclosure include reducing the thickness of the flexure 140 at the hinge portion 140B of the flexure 140. As used herein, a "hinge portion" of a feature refers to any portion of the feature that intersects and/or overlaps with hinge 140. Accordingly, the hinge portion 140B of the flexure 140 is a portion of the flexure 140 approximately within the area shown in phantom in fig. 2. Correspondingly, the hinge portion 110B of the second layer 110 of the flexure 140 is a portion of the second layer 110 within the hinge portion 140B, as shown in fig. 5A and 5B.

The stiffness of the hinge 141 (i.e., the stiffness of the hinge portion 140B of the flexure 140) will affect the fly height. If the hinge portion 140B is relatively stiff, the load bar 196 will not be able to position itself to minimize fly height because rotation about the hinge 141 will be limited. Accordingly, a system and method that minimizes the stiffness around the hinge 141 would be beneficial. In addition, the stress acting on the hinge portion 140B causes the fly height to vary. Gram load, or reaction force at hinge 141 for loading head 134 on surface 116 at a desired flying height, varies due to stress (e.g., backward bending stress or thermal stress) in hinge region 140B. This can lead to undesirable changes in fly height, ultimately affecting signal quality. In some cases, these variations may be compensated for by thermal fly height control ("TFC"). For example, a TFC slider, such as slider 142, may control the fly height. However, too large a variation cannot be compensated by TFC. Thus, in some examples, it may be preferable to improve fly height control by reducing stress in hinge portion 140B.

Fig. 3 is a flow diagram of a method 300 of manufacturing a suspension assembly 135 of a magnetic storage device 100 according to one or more examples of the present disclosure. Specifically, the method 300 includes manufacturing the flexure 140 of the suspension assembly 135 of the magnetic storage device 100. Some of the steps of method 300, as well as additional steps of a method of forming a multi-layer flexure 140 according to one or more examples of the present disclosure, are graphically illustrated in fig. 4A-4O, which are cross-sectional views of a suspension assembly 135 of a magnetic storage device 100. Thus, some of the steps graphically shown in fig. 4A-4O include the steps of the method 300 shown in fig. 3. However, fig. 4A-4O graphically show additional steps in addition to those listed in fig. 3. Those of skill in the art will appreciate that any combination of the steps shown in fig. 3 and fig. 4A-4O and/or described herein may be employed.

As shown in fig. 4A and 4O, the suspension assembly 135 includes a flexure 140 designed to reduce stress in the hinge portion 140B, or a portion overlapping the hinge 141. The flexure 140 is a multi-layer flexure including, for example, a first layer 119, a second layer 110, and a third layer 124. As will be described herein, portions of each layer 119, 110, and/or 124 have various thicknesses in order to minimize stress in hinge portion 140B.

The method 300 includes a first step 340 of forming a first layer of the flexure 140 (i.e., layer 119 in fig. 4A-4M). In some examples, the first layer 119 is formed directly on the load bar 196. Similar to load bar 196, first layer 119 is typically made of stainless steel or other similar material and has a thickness greater than the other layers of multilayer flexure 140. In some examples, the first layer 119 is made of a metallic material. For example, in some examples, the first layer 119 is a stainless steel sheet. According to some examples, the first layer 119 has a thickness of about 20 micrometers ("μm") (t 2 as shown in fig. 5A). In some examples, after forming the multi-layer flexure 140, the first layer 119 is attached to the load bar 196 to attach the entire flexure 140 to the load bar. In other words, the first layer 119 is positioned immediately adjacent the load bar 196.

Because the first layer 119 is typically made of stainless steel or other metallic material, having a relatively high thickness, in some examples, it is preferable that the first layer 119 not extend above the hinge 141 to avoid applying increased downward pressure to the carrier arm 105 (e.g., the head 134) when the carrier arm 105 (and thus the load bar 196) is in place to hover over the disk 115. Avoiding the application of increased pressure helps to prevent fly height variations. Thus, as shown in fig. 5A, there is a gap 144 in the first layer 119. The gap 144 is substantially aligned with the hinge region 140B and thus with the hinge 141. In addition, the gap is substantially aligned with the hinge portion 110B of the second layer 110, which hinge portion 110B has a reduced thickness t4 as compared to the thickness t3 of the non-hinged portion 110A of the second layer 110, so as to accommodate bending about the hinge 141, as shown in fig. 5B.

The second layer 110 of the flexure 140 is formed (e.g., applied) on the first layer 119 (i.e., step 342 in fig. 3). In some examples, the second layer 110 is made of a dielectric and/or photosensitive material (e.g., liquid polyimide). As shown in fig. 5A, the second flexure layer 110 forms a barrier between the first layer 119 and the third layer 124. This is important to maintain signal quality. The thickness of the second layer 110 is positively correlated with the signal quality. However, too thick a second layer 110 in the hinge region 140B may create tension in the hinge region 140B. This tension contributes to the spring force of the hinge 141 against the carrier arm 105, thus causing a change in fly height between the head 134 and the top surface 116 of the disk 115. Thus, while removing the first layer 119 from the hinge portion 140B may reduce the stress in the hinge portion 140B, reducing the thickness t4 of the hinge portion 110B of the second layer 110 may further reduce this stress. Thus, examples of the present disclosure reduce the tension in hinge region 140B, thereby reducing fly height variation.

After the second layer 110 is formed over the first layer 119, a mask (e.g., mask 120 of fig. 4A) is placed over the second layer 110 (step 344 of fig. 3). Although the phrase "disposed above … …" is used herein, examples of the present disclosure are not limited thereto. For example, the mask 120 may be formed on the second layer 110. This mask 120 includes a portion 120B positioned over a hinge portion 140B of the flexure 140. This portion 120B differs from the rest 120A of the mask 120 in terms of translucency. Portion 120B is substantially aligned with hinge portion 140B. In some examples, portion 120B is more translucent than portion 120A. In some examples, mask 120 is a glass photomask and/or a halftone mask. For example, hinge portion 120B of mask 120 is a half tone glass mask and the remaining portion 120A of mask 120 is a full glass mask.

In some examples, the mask 120 is an opaque plate, or transparent or translucent portion, having one or more apertures. Thus, light may be irradiated through the mask 120. In some examples, the portion 120B aligned with the hinge portion 140B is more translucent than the remaining portion 120A. In other words, portion 120B is aligned with portion 110B of second layer 110 where a lesser thickness is desired (e.g., t4 of fig. 5A). In some examples, the greater translucency of mask 120 in portion 120B is due to the translucency of the material used to form portion 120B being higher than the material used to form the remaining portion 120A. In some examples, the greater translucency is due, at least in part, to a greater number and/or concentration of apertures and/or transparent portions in portion 120B.

As indicated at step 346 in fig. 3, light is irradiated through the mask 120. The light is irradiated through the hinge portion 120B and the fixing portion 120A of the mask 120. In some examples, this is done through a lens. Although the portion 120B is more translucent than the remaining portion 120A, light may still be irradiated through the entire mask 120.

Mask 120 is then removed from second layer 110. The next step 348 involves etching away or removing residues from the second layer 110 such that the hinge portion 110B of the second layer has a thickness t4 that is less than the thickness t3 of the remaining non-hinge portion 110A of the second layer 110. The non-hinge portion 110A may also be referred to herein as a "fixed portion".

This example is shown in fig. 4B. Illuminating light through the mask 120 allows portions of the hinge portion 110B to be removed more easily later. Thus, the use of the mask 120 allows the thickness of the hinge portion 110B to be reduced by a less dense process.

In some examples, thickness t3 is approximately twice thickness t4. For example, the non-hinge portion 110A has a thickness t3 of ten micrometers ("μm") and the etched hinge portion 110B has a thickness t4 of 5 μm. However, examples of the present disclosure are not limited thereto. In some examples, the thickness t3 of the etched portion 110B is between thirty percent and seventy percent of the thickness t4 of the remaining non-hinged portion 110A. The difference in thicknesses t3 and t4 creates notch 197 in second layer 110.

In some examples, due to the different translucency, the hinge portion 110B is substantially aligned with the portion 120B of the mask 120 having the greater translucency, and the non-hinge portion 110A is substantially aligned with the remaining portion 120A of the mask 120 having the lesser translucency.

As shown in fig. 4C, in some examples, a photoresist material 113 is formed on the second layer 110. For example, the photoresist material 113 is a dry film photoresist. In some examples, the photoresist material 113 is formed on the second layer 110 by first attaching a layer of the photoresist material 113 to the second layer 110 and then forming the layer of the photoresist material 113 through a mask. In some examples, the mask is similar to mask 120 used to form different thicknesses t3 and t4 of second layer 110, as shown in fig. 4A.

The photoresist material 113 is also formed on the first layer 119 on a side that does not contact the second layer 110. The photoresist material 113 is formed on the layers 110 and 119 of the flexure by first attaching the photoresist material 113. Although not shown in fig. 4C, in some examples, photoresist material 113 is then formed on layers 119 and 110 by irradiating ultraviolet ("UV") light through a patterned glass mask. The layers of photoresist material 113 may be referred to herein as "fourth layer", "fifth layer", "sixth layer", and/or "seventh layer" of the flexure 140. However, as will be described herein, in some examples, the process of forming the multilayer flexure 140 involves removing one or more layers of photoresist material 113 after that photoresist material has reached its purpose (i.e., after a portion of the corresponding layer 110, 119 of the flexure has been removed).

As shown in fig. 4D, one or more openings 111 are etched into the photoresist material 113. Fig. 4D shows a cross-section of suspension assembly 135 in a plane perpendicular to the plane of the cross-section shown in fig. 4C. As shown in fig. 4D, one or more openings 111 may expose portions of the first second layer 110, which is a layer having the etched photoresist material 113 formed thereon.

As shown in fig. 4E, in some examples, an additional third layer is added to the flexure 140. As shown in fig. 4J, each of the fixed portions 140A of the flexures 140 includes a third layer 124. In some examples, only the fixed portion 140A includes the third layer 124. In other examples, both the fixed portion 140A and the hinge portion 140B include a third layer. In those examples, the third layer 124 is made of a material that is relatively soft and does not create undue tension in the hinge 141 as the material of the first layer 119 (e.g., stainless steel). For this reason, the third layer 124 may be included in the hinge portion 140B without generating a change in the flying height of the head 134.

In some examples, the third layer (e.g., layer 124 shown in fig. 4E-4M and 5A-5B) is made of copper. In some examples, the copper of the third layer 124 has a high purity, making it less hard and more flexible. For example, the third layer 124 includes copper having a purity that exceeds ninety-nine percent of the purity of the electronic grade copper foil or is similar to the purity of the electronic grade copper foil.

As shown in fig. 4E, in some examples, the third layer 124 is formed on the second layer 110 by depositing a material intended to form the third layer 124 into the opening 111 of the photoresist 113. For example, material is deposited into opening 111 until enough material is deposited to form third layer 124 having a thickness t5 (fig. 4E) of approximately six micrometers ("μm"). As shown in fig. 4A to 5B, the second layer 110 is interposed between the first layer 119 and the third layer 124. In some examples, the thickness t5 of the third layer 124 is greater than the thickness t4 of the hinge portion 110B of the second layer 110, but less than the thickness t2 of the first layer 119. In other examples, the thickness t5 of the third layer 124 is substantially equal to the thickness t3 of the non-hinge portion 110A of the second layer 110, but still less than the thickness t2 of the first layer 119. In other examples, each of thicknesses t2, t3, and t5 is approximately equal, and thickness t4 is less than any of thicknesses t2, t3, and t 5.

In some examples, the third layer 124 is part of one or more signal traces of the flexure 140. In some examples, the flexure 140 includes signal traces (sometimes referred to as "circuit traces") to conduct signals from the read-write head 134 to other components of the device 100. Although such traces are typically made of copper and/or copper foil, examples of the present disclosure are not limited thereto. For example, in some examples, the traces are made of aluminum, gold, or any combination thereof. The width w of the opening 111 is equal to the desired width w of the trace of the flexure 140. The number of openings 111 is the desired number of copper traces for the flexure 140. For example, as shown in fig. 4D and 4E, two openings 111 are used to form two traces on the flexure 140.

Although not shown herein, in some examples, a cross-section of the suspension assembly 135 perpendicular to the cross-section shown in fig. 4E may be presented similar to the cross-section shown in fig. 4C, the cross-section shown in fig. 4C including a bottom layer of photoresist material 113, a first layer 119 of a flexure, a second layer 110 of a flexure having a different thickness, and a top layer of photoresist material 113. In some examples, the top layer of photoresist material 113 is substantially uniform in thickness, but includes a recess 136 that fills the thickness difference between the hinge portion 110B of the second layer 110 having the smaller thickness t4 and the portion 110A having the larger thickness t 3.

Photoresist material 113 is removed from the flexures 140. In some examples, this is done by chemical cleaning. After removal of the photoresist material 113, the flexure includes a first layer 119, a second layer 110, and a third layer 124, as shown in fig. 4F. The second layer 110 includes a hinge portion 110B that has a thickness that is less than the non-hinge portion 110A and also less than the thickness of the first layer 119. The third layer 124 is substantially uniform in thickness and includes a notch 138 due to its proximity to the second layer 110.

Fig. 4G is a cross-sectional view of suspension assembly 135 at the stage shown in fig. 4F, wherein the plane of the view of fig. 4G is perpendicular to the plane of the view of fig. 4F. As shown in fig. 4F, in some examples, the suspension assembly 135 includes two copper traces 124.

At this stage, portions of the first layer 119 still need to be removed to ensure that the hinge portion 140B of the flexure 140 does not include any rigid material of the first layer 119. Thus, as shown in fig. 4H, more photoresist material 113 is attached to the flexure 140 to enable removal of portions of the first layer 119. In some examples, the photoresist material 113 is deposited over the third layer 124. However, examples of the present disclosure are not limited thereto. For example, the photoresist material 113 is formed only on certain portions of the first layer 119.

As shown in fig. 4H, photoresist material 113 is formed on portions of first layer 119 that are not removed to accommodate hinge region 140B. In other words, the photoresist material 113 is attached to portions of the first layer 119 that do not intersect or overlap the hinge portions 140B when the flexure 140 is placed on the load bar 196.

Fig. 4I is a cross-section of suspension assembly 135 at the stage shown in fig. 4H. However, the cross-section of fig. 4I is perpendicular to the cross-section shown in fig. 4H. The cross-section of fig. 4I is within a portion 110B of the second layer 110 that will be substantially aligned with the hinge portion 140B of the flexure 140. Thus, only the photoresist 113 of the cap layer 124 (which in some examples is a trace) is shown in fig. 4I.

As shown in fig. 4J, portions of the first layer 119 are removed such that the hinge portion 140B does not include any portion of the first layer 119. In other words, all of the first layer 119 of the hinge portion 140B is removed. The photoresist 113 is used to hold portions of the second layer 110 in place while other portions are removed. In some examples, the removing is accomplished by etching.

Fig. 4K shows a cross-sectional view of the suspension assembly 135 within the hinge region 140B of the flexure 140. The cross-section shown in fig. 4K is perpendicular to the cross-section shown in fig. 4J. As shown in fig. 4K, the only portions of the flexure 140 that are included in the hinge portion 140B are the portion 110B of the second layer 110 and the third layer 124 (or trace). To illustrate an example in which the photoresist material 113 is also applied to the top of the second layer 110 while portions of the first layer 119 are removed, the photoresist material 113 is also shown in fig. 4K.

As shown in fig. 4L, the photoresist material 113 is then removed. In some examples, this is performed by chemical cleaning, as described in connection with fig. 4F.

Fig. 4M shows a cross-sectional view of the suspension assembly 135 within the hinge region 140B of the flexure 140. The cross-section shown in fig. 4M is perpendicular to the cross-section shown in fig. 4L in the gap 144 of the first layer 119.

Fig. 4N shows a cross section of an assembly 135 that intersects the hinge portion 140B in the gap 199 of the load bar 196 shown in fig. 2. As shown in fig. 4N, the final step of the method includes attaching the flexure 140 to the base 192 and the load bar 196 such that the portion 110B of the second layer spans the hinge portion 141 of the load bar 196. For example, load bar 196 is attached to the opposite side of first layer 119 from second layer 110.

In the example illustrated in fig. 4N, assembly 135 is in a straight, unbent position. Hinge 141 is shown in fig. 4N. In some examples, the hinge 141 is positioned on one or more sides of a gap 199 in the load bar 196 shown in fig. 2.

The flexure 140 is attached to and movable with the base plate 192 and the load bar 196. The first layer 119, the second layer 110, and the third layer 124 of the flexure 140 are arranged in a stack. The second layer 110 is interposed between the first layer 119 and the third layer 124. The flexure 140 includes a hinge portion 140B that overlaps the hinge 141 of the load bar. The flexure 140 also includes a fixed portion 140A adjacent to the hinge portion 140B. Each of the fixed portions 140A of the flexure 140 includes a first layer 119 and a second layer 110. The first layer 119 is interposed between the second layer 110 and the load bar 196.

Because the second layer 110 is formed of a material that allows it to bend about the hinge 141 (e.g., liquid polyimide), the hinge portion 140B of the flexure includes the hinge portion 110B of the second layer 110. However, the hinge portion 140B does not include the first layer 119, allowing the first layer 119 to be formed of a material having a higher hardness. In addition to the lower stiffness of the material of the second layer 110 compared to the material of the first layer 119, the reduced thickness t4 of the hinge portion 110B also reduces the tension in the hinge region 140B compared to the thickness t3 of the non-hinge portion 110A of the second layer 110, thereby minimizing fly height variation. In some examples, the ratio of t3 to t4 is greater than 1 and no more than 2.4. For example, if t4 is 5 μm and t3 is about 10 μm, then the ratio of t3 to t4 is 2.

The first layer 119 has a uniform thickness t2 and a gap 144 extending through the hinge portion 140B. Thus, hinge portion 140B includes second layer 110 (e.g., portion 110B of the second layer) but does not include first layer 119. In some examples, the hinge portion 140B also includes at least a portion of the third layer 124. The load bar 196 also has a substantially uniform thickness t1 at least along the hinge 141. The second layer 110 of the flexure 140 has two portions 110A and 110B, each having a different thickness. The portion 110B that overlaps the gap 144 and the hinge 141 (and is part of the hinge portion 140B of the flexure 140) has a thickness t4 that is less than the thickness t3 of the portion 110A that does not overlap the portion 110B. The third layer 124 has a uniform thickness t5.

In fig. 4O, the flexure 140 and load bar 196 of fig. 4N are bent about the hinge 141 to move relative to the base plate 192. Thus, a distal portion of the load bar 196 (e.g., portion 133 shown in fig. 2) moves relative to the base plate 192. When the load bar 196 is bent as shown in fig. 4O, it is bent toward the surface 116 of at least one disk (e.g., disk 115 shown in fig. 1), thereby minimizing the fly height between the head 134 of the distal portion 133 and the surface 116. For example, if the disk 115 is positioned below the load bar 196, bending the load bar 196 and the flexure 140 about the hinge 141 brings the distal portion 133 closer to the surface 116 of the disk 115.

Although fig. 4N and 4O illustrate the third layer 124 as part of both the fixed portion 140A and the hinge portion 140B (i.e., running along the entire second layer 110), examples of the present disclosure are not limited thereto. Some examples include gaps in the third layer 124 that are similar to the gaps 144 in the first layer 119. In such examples, only the fixed portion 140A includes the third layer 124; the hinge portion 140B does not include the third layer.

Fig. 4N and 4O show the gap 144 in the first layer 119 and the recesses 197 in the second layer 110 and the third layer 124. Notch 197 is due to: (1) Differences in thickness t3 and t4 between the non-hinge portion 110A and the hinge portion 110B, respectively, of the second layer; (2) Forming a hinge portion 110B by removing material of the second layer 110 on a side opposite to a side of the second layer 110 contacting the first layer 119 (as shown in fig. 4B); and (3) the third layer 124 is formed directly on the notch 197 of the second layer 110 (e.g., notch 197 shown in fig. 4B). In other words, the second portion 110B opens toward the third layer 124.

However, examples of the present disclosure are not limited thereto. Fig. 5A and 5B are cross-sectional views of a suspension assembly 135 of a magnetic storage device 100 perpendicular to a hinge 141 in a gap of a load bar 196 (e.g., gap 199 in fig. 2) according to one or more examples of the present disclosure. As shown in fig. 5A through 5B, material of the second layer 110 may be removed from a side of the second layer facing the first layer 119. Thus, the side of the second layer 110 on which the third layer 124 is formed is relatively flat, and thus there is no recess 197 in the side of the second layer 100 or in the third layer 124. The second portion 110B defines a recess that opens toward the gap 144, but not toward the third layer 124.

Fig. 5A shows the suspension assembly 135 in a straight, unbent position. Fig. 5B is a cross-sectional view of the suspension assembly 135 of fig. 5A having the flexure 140 and load bar 196 bent slightly about a hinge 141 interposed between a distal portion (e.g., distal portion 133 shown in fig. 2) and the base plate 192.

Portion 110B may be referred to herein as a "second layer of hinge portion 140B. The portion 110A having the thickness t3 in fig. 5B may be referred to as a "second layer of the fixed portion 140A".

As used herein, the term "layer" may be used to describe a plurality of continuous or discontinuous layers. However, it may also be used to describe portions of a material layer. For example, as shown in fig. 5A, the second layer 110 includes multiple portions having different thicknesses, including portions 110A and 110B. Portions 110A and 110B may be collectively referred to as "a plurality of second layers 110" and/or "the second layers 110". In addition, portion 110A may be referred to as a "second layer of the fixed portion 140A of the flexure.

In the above description, certain terms may be used, such as "upper," "lower," "horizontal," "vertical," "left," "right," "above," "below," and the like. These terms are used where applicable to provide some clarity of description in handling relative relationships. These terms are not intended to be implied by absolute relationship, position and/or orientation. For example, for an object, the "upper" surface may be changed to a "lower" surface by simply turning the object over. Nevertheless, it is still the same object. Furthermore, unless expressly stated otherwise, the terms "comprising," including, "" having, "and variations thereof herein mean" including but not limited to. The enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms "a," "an," and "the" also mean "one or more" unless expressly specified otherwise. Furthermore, the term "plurality" may be defined as "at least two".

As used herein, a system, device, structure, article, element, component, or hardware that is "configured to" perform a specified function is actually able to perform that specified function without any change, rather than merely that it is able to perform a further modified specified function. In other words, a system, device, structure, article, element, component, or hardware "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing the specified function. As used herein, "configured to" means an existing characteristic of a system, device, structure, article, element, component, or hardware that enables the system, device, structure, article, element, component, or hardware to perform a specified function without further modification. For the purposes of this disclosure, a system, device, structure, article, element, component, or hardware described as "configured to" perform a particular function may additionally or alternatively be described as "adapted" and/or "operable to" perform the recited function.

In addition, examples of "coupling" one element to another element in this specification may include direct and indirect coupling. A direct coupling may be defined as one element being coupled to and making some contact with another element. An indirect coupling may be defined as a coupling between two elements that are not in direct contact with one another, but with one or more additional elements between the coupled elements. Further, as used herein, securing one element to another element may include direct securing and indirect securing. In addition, as used herein, "adjacent" does not necessarily mean in contact. For example, one element may be adjacent to another element without contacting the element.

As used herein, the phrase "at least one of" when used with a list of items means that different combinations of one or more of the listed items may be used and that only one of the items in the list may be required. An item may be a particular object, thing, or category. In other words, "at least one of" means that any combination of items in a list or any number of items may be used, but not all items in the list may be required. For example, "at least one of item a, item B, and item C" may mean item a; item a and item B; item B; item a, item B, and item C; or item B and item C. In some cases, "at least one of item a, item B, and item C" may mean, for example, but not limited to, two of item a, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

Unless otherwise indicated, the terms "first," "second," and the like are used herein merely as labels, and are not intended to impose order, position, or hierarchical requirements on the items to which these terms refer. Furthermore, references to items such as "second" do not require or exclude the presence of items such as "first" or lower numbered items and/or items such as "third" or higher numbered items.

The schematic flow chart diagrams included herein are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of one example of the presented method. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated method. Additionally, the format and symbols employed are provided to explain the logical steps of the method and are understood not to limit the scope of the method. Although various arrow types and line types may be employed in the flow chart diagrams, they are understood not to limit the scope of the corresponding method. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the method. For example, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted method. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

The inventive subject matter may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The described examples are to be considered in all respects only as illustrative and not restrictive. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (20)

1. A suspension assembly for a magnetic storage device, the suspension assembly comprising:

A bottom plate;

A load bar attached to the base plate and comprising a distal portion and a hinge, wherein the hinge is interposed between the distal portion and the base plate and is configured to flex such that the distal portion moves relative to the base plate; and

A flexure attached to the base plate and the load bar, wherein:

the flexure includes a hinge portion and a fixed portion adjacent to the hinge portion, the hinge portion overlapping at least a portion of the hinge of the load bar;

each of the fixed portions of the flexure includes a first layer and a second layer;

the first layer is interposed between the second layer and the load bar;

the hinge portion of the flexure includes the second layer but does not include the first layer such that a gap is defined between the first layers of the fixed portion of the flexure; and is also provided with

The thickness (t 4) of the second layer of the hinge portion of the flexure is less than the thickness (t 3) of the second layer of the fixed portion of the flexure.

2. The suspension assembly of claim 1 wherein a ratio of the thickness of a second layer of the fixed portion to the thickness of the second layer of the hinge portion is greater than 1 and no more than 2.4.

3. The suspension assembly of claim 1 wherein the load bar is made of a metallic material.

4. The suspension assembly of claim 1 wherein the first layer is made of a metallic material.

5. The suspension assembly of claim 1 wherein the first layer is directly adjacent to the load bar.

6. The suspension assembly of claim 1 wherein each of the fixed portions of the flexure further comprises a third layer.

7. The suspension assembly of claim 6 wherein the second layer is interposed between the first layer and the third layer.

8. The suspension assembly of claim 6 wherein the third layer has a substantially uniform thickness.

9. The suspension assembly of claim 6 wherein the third layer is made of copper.

10. The suspension assembly of claim 6 wherein the first, second and third layers are arranged in a stack.

11. The suspension assembly of claim 1 wherein the second layer is made of a photosensitive polyimide material.

12. The suspension assembly of claim 1 wherein the second layer is made of a dielectric material.

13. A magnetic storage system, comprising:

A bottom plate;

a number of disks; and

A bracket arm, comprising:

A load bar attached to the base plate and comprising:

A distal portion;

A hinge, wherein the hinge is interposed between the distal portion and the base plate and is configured to flex such that the distal portion moves relative to the base plate; and

A flexure attached to the base plate and the load bar,

Wherein:

the flexure includes a hinge portion and a fixed portion adjacent to the hinge portion, the hinge portion spanning the hinge of the load bar;

each of the fixed portions of the flexure includes a first layer and a second layer;

the first layer is interposed between the second layer and the load bar;

the hinge portion of the flexure includes the second layer but does not include the first layer such that a gap is defined between the first layers of the fixed portion of the flexure that spans the hinge; and is also provided with

The thickness (t 4) of the second layer of the hinge portion of the flexure is less than the thickness (t 3) of the second layer of the fixed portion of the flexure.

14. The magnetic storage system of claim 13, wherein a ratio of the thickness of the fixed portion to the thickness of the second layer of the hinge portion is greater than 1 and no more than 2.4.

15. The magnetic storage system of claim 13, wherein the hinge is biased toward a surface of at least one of the number of disks to allow a head of the distal portion to read data from or write data to the at least one disk.

16. A method of manufacturing a suspension assembly for a magnetic storage device, the method comprising:

forming a second layer over the first layer;

Applying a mask to the second layer, wherein a translucency of a first portion of the mask is different from a translucency of a second portion of the mask;

Illuminating light through the first and second portions of the mask;

removing the mask from the second layer; and

The second layer is etched such that a first portion of the second layer to which the first portion of the mask is applied has a first thickness and a second portion of the second layer to which the second portion of the mask is applied has a second thickness, wherein the second thickness is less than the first thickness.

17. The method as recited in claim 16, further comprising:

Forming a third layer on the second layer by etching at least a portion of the fourth layer after forming a fourth layer over the second layer and forming a fifth layer under the first layer;

removing the fourth layer and the fifth layer by chemical cleaning;

forming a sixth layer on the third layer;

Forming a seventh layer below the first layer;

Removing a portion of the first layer and a portion of the seventh layer, wherein each removed portion is aligned with the second portion of the mask; and

And removing the sixth layer and the seventh layer.

18. The method of claim 16, wherein a portion of the mask comprises a halftone glass mask.

19. The method according to claim 16, wherein:

the first layer is made of stainless steel;

the second layer is made of polyimide material;

the third layer is made of copper; and is also provided with

Each of the fourth layer, the fifth layer, the sixth layer, and the seventh layer is made of a dry film photoresist.

20. The method of claim 16, further comprising attaching the flexure to a base plate and a load bar such that the second portion of the second layer spans a hinge portion of the load bar.