CN115592488A - Chip polishing method - Google Patents

Abstract

The invention discloses a chip polishing method, which comprises the following steps: preparing a sample to be processed and a hard bearing sheet, wherein the sample comprises a chip and a frame, the chip is connected to the front surface of the frame, and the bearing sheet is provided with a first surface and a second surface which are oppositely arranged; attaching the back surface of the frame to the first surface of the bearing sheet; at least coating the outer side surface of the chip with an isolation layer, coating the outer side surface of the isolation layer with an enhancement layer, and exposing at least the second surface of the bearing sheet; polishing the chip from the second surface until the chip has a residual set thickness; the isolation layer is removed to separate the sample from the enhancement layer. The back of sample and the laminating of the first surface of carrier sheet do not have the adhesive between the two, and consequently the sample can not be crooked because of the relative carrier sheet of adhesive thickness inequality, helps improving the inhomogeneous problem of chip thickness after polishing.

Description

Chip Polishing Method

technical field

The invention relates to the field of failure detection of semiconductor devices, in particular to a chip polishing method.

Background technique

In the failure detection of the chip, in order to find out the defects inside the chip, it is necessary to polish the back of the chip, so that the internal defects of the chip can be observed through an infrared microscope, or the failure point can be located by using an EMMI (micro-light microscope) . In the related art, the front side of the chip is usually bonded to the jig with an adhesive, and then the jig is fixed on the grinding equipment, and the back side of the chip is polished. Since the flow of the adhesive is difficult to control, the sticking Adhesives are prone to the problem of uneven thickness, the chip cannot be fixed horizontally, and the amount of polishing in different areas is inconsistent in the subsequent polishing process, resulting in uneven thickness of the finally obtained chip, which affects the test results.

Contents of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the present invention proposes a chip polishing method, which can improve the problem of uneven thickness of the chip after polishing.

The chip polishing method according to the first embodiment of the present invention includes the following steps:

Prepare a sample to be processed and a hard carrier sheet, the sample includes a chip and a frame, the chip is connected to the front of the frame, and the carrier sheet has a first surface and a second surface oppositely arranged;

bonding the back of the frame to the first surface of the carrier sheet;

Coating an isolation layer at least on the outer side of the chip, and coating a reinforcing layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet;

Grinding the chip from the second surface until the chip has a predetermined remaining thickness;

The isolation layer is removed to separate the sample from the reinforcement layer.

The chip polishing method according to the first embodiment of the present invention has at least the following beneficial effects:

The back of the sample is attached to the first surface of the carrier sheet, and there is no adhesive between the two, so the sample will not be skewed relative to the carrier sheet due to uneven thickness of the adhesive, which helps to improve the uneven thickness of the chip after polishing The problem.

In other embodiments of the present invention, the isolation layer is made to cover the outer surface of the frame except the back surface, and the isolation layer is connected to the first surface of the carrier sheet.

In other embodiments of the present invention, the method for setting the isolation layer includes:

applying a solid isolation material on top of the chip after the sample is placed on the carrier;

heating the isolation material to melt the isolation material and flow down to the carrier sheet to cover the chip and the frame;

The molten barrier material is solidified to form the barrier layer.

In other embodiments of the present invention, the material of the isolation layer is paraffin, and the heating temperature is 100°C to 105°C.

In other embodiments of the present invention, the reinforcing layer is made to cover other outer surfaces of the carrier sheet except the second surface.

In other embodiments of the present invention, the method for setting the enhancement layer includes:

setting a mold with an accommodating cavity, placing the carrying sheet carrying the sample in the mold, and making the second surface fit the bottom wall of the accommodating cavity;

Adding a liquid reinforcement material into the accommodating cavity until the liquid level is higher than the isolation layer;

The reinforcing material in a liquid state is cured to form the reinforcing layer.

In other embodiments of the present invention, the material of the reinforcing layer is resin.

In other embodiments of the present invention, the carrier sheet, the frame and the chip are respectively polished with sandpaper of increasing mesh.

The chip polishing method according to the fifth embodiment of the present invention includes the following steps:

preparing a carrier sheet and chips to be processed, the carrier sheet has a first surface and a second surface oppositely arranged;

bonding the back of the chip to the first surface of the carrier sheet;

Coating an isolation layer on the outer side of the chip, and coating a reinforcement layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet;

Grinding starts from the second surface until the chip reaches a set thickness;

The isolation layer is removed to separate the chip from the enhancement layer.

The chip polishing method according to the sixth embodiment of the present invention includes the following steps:

Prepare a carrier sheet and a sample to be processed, the sample includes a molded body, and a chip and a frame located in the molded body, the chip is connected to the front of the frame, and the carrier sheet has a first surface and second surface;

bonding the back side of the molding body to the first surface of the carrier sheet;

Coating an isolation layer on the outer side of the molded body, and coating a reinforcement layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet;

Grinding the chip from the second surface until the chip has a predetermined remaining thickness;

The isolation layer is removed to separate the sample from the reinforcement layer.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, wherein:

Fig. 1 is a brief schematic diagram of the connection between a chip and a jig in the related art;

Fig. 2 is a brief schematic diagram of a chip polished in the related art;

Fig. 3 is a schematic diagram of the internal structure of a typical sample applicable to the present invention;

Fig. 4 is a state change diagram of the sample when the polishing method of the first embodiment is used;

Fig. 5 is a schematic diagram of chamfering on the side of the chip after being polished by the related technology;

Fig. 6 is a state change diagram of the sample when the polishing method of the second embodiment is used;

7 is a schematic diagram of forming an isolation layer in the second embodiment;

Fig. 8 is a state change diagram of the sample when the polishing method of the third embodiment is used;

Fig. 9 is a schematic diagram of forming a reinforcement layer in the third embodiment;

Fig. 10 is a state change diagram of the sample when it is polished by the polishing method of the fourth embodiment;

Fig. 11 is a state change diagram of the sample when it is polished by the polishing method of the fifth embodiment;

Fig. 12 is a state change diagram of the sample when polished by the polishing method of the sixth embodiment.

Reference signs:

The carrier sheet 100, the first surface 110, and the second surface 120;

Sample 200, molded body 210, chip 220, frame 230;

isolation layer 300;

enhancement layer 400;

heating device 500;

mold 600, accommodating cavity 610;

Sample 10, chamfer 11, adhesive 20, jig 30.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals designate the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc. indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only In order to facilitate the description of the present invention and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, several means more than one, and multiple means more than two. Greater than, less than, exceeding, etc. are understood as not including the original number, and above, below, within, etc. are understood as including the original number. If the description of the first and second is only for the purpose of distinguishing the technical features, it cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features relation.

In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

In the description of the present invention, reference to the terms "one embodiment," "some embodiments," "exemplary embodiments," "examples," "specific examples," or "some examples" is intended to mean that the embodiments are A specific feature, structure, material, or characteristic described by or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the related art, if it is necessary to polish the chip to analyze internal defects, usually the back of the sample 10 to be processed is bonded to the jig 30 through the adhesive 20. Before bonding, it is necessary to apply the flowable adhesive 20 However, the flow of the adhesive 20 is difficult to accurately control, resulting in the problem of uneven thickness of the adhesive, even if the thickness of the adhesive 20 can be kept uniform before bonding, The sample 10 is easily skewed during the docking process with the jig 30 , and finally forms the skewed state shown in FIG. 1 .

When the sample 10 is ground in contact with the horizontal grinding surface in the skewed state shown in FIG. The amount of grinding is more than that on the right side, and the left side of the finally obtained sample 10 is thinner than the right side. In this way, when the thickness of the left side of the sample 10 meets the requirements, the right side may not be clearly visible because it is too thick The internal structure affects the detection results. Based on this, the present invention proposes a chip grinding method, which can ensure that the chip 220 has a uniform thickness after grinding, which will be described in detail below with reference to the accompanying drawings.

The sample 200 applicable to the polishing method in the first embodiment of the present invention may be a power module. As shown in FIG. The side surface connected with the leads is positioned as the front side of the chip 220, and the side surface opposite to the front side is the back side. Specifically, in FIG. 3, the upper surface of the chip 220 is the front side, and the lower surface is the back side. It should be noted that, for the convenience of description, for other components mentioned in the present invention, the upper surface when placed horizontally is used as the front, and the lower surface is used as the back. Based on this, the back of the chip 220 is connected to the front of the frame 230.

The sample 200 applicable to this embodiment may also include a molded body 210, the material of the molded body 210 is usually epoxy resin, and the molded body 210 wraps the chip 220 and the frame 230 to play the role of insulation and protection . In order to reduce the amount of grinding, the molding body 210 on the sample 200 is usually removed first to expose the chip 220 and the frame 230 , wherein the molding body 210 on the outside of the sample 200 can be removed by using an acid solution. It should be noted that the molded body 210 may be attached to the sample 200 as an incoming material, and the molded body 210 needs to be removed before polishing, and the molded body 210 can also be removed from the sample 200 before the incoming material.

Referring to FIG. 4 , it shows a state change diagram of the sample 200 when the grinding method of the first embodiment is used for grinding. According to the sequence from top to bottom, the grinding method includes the following steps:

Step 1: Prepare the sample 200 from which the molding body 210 has been removed. The sample 200 includes the frame 230 and the chip 220 placed on the front side of the frame 230 .

Step 2: Place the sample 200 on the carrier sheet 100, the carrier sheet 100 has a first surface 110 and a second surface 120, wherein the first surface 110 is located on the upper side of the illustration, and the second surface 120 is located on the lower side of the illustration Specifically, the sample 200 is attached to the first surface 110 of the carrier sheet 100 through the back of the frame 230 . The carrier sheet 100 is a hard sheet with uniform thickness, which can avoid deformation of the carrier sheet 100 and can be used as a reference to realize the horizontal placement of the sample 200. In some specific embodiments, the carrier sheet 100 can be a metal sheet, such as a copper sheet , the copper sheet has a certain strength to support the sample 200, and at the same time, the hardness will not be too high to increase the difficulty of grinding. The supporting sheet 100 can also be a glass sheet or a ceramic sheet, so as to further avoid deformation and have higher flatness. It should be noted that, on the basis of ensuring that the chip 220 can be supported horizontally, the carrier sheet 100 should be as thin as possible to reduce the workload of subsequent grinding.

Step 3: Cover the outer surface of the chip 220 with the isolation layer 300 . The outer surface of the chip 220 here refers to other surfaces except the back surface of the chip 220 . The isolation layer 300 can be removed under set conditions, which is convenient for taking out the polished sample 200 .

Step 4: Coating the reinforcement layer 400 on the outer side of the isolation layer 300 , the outer side of the isolation layer 300 refers to other surfaces except the back side of the isolation layer 300 bonded to the frame 230 . In addition to covering the isolation layer 300, the reinforcement layer 400 is also connected to the carrier sheet 100, for example, to the first surface 110 of the carrier sheet 100, thereby connecting the carrier sheet 100, the sample 200, the isolation layer 300 and the reinforcement layer 400 as a whole For the assembly to be polished, the reinforcement layer 400 has relatively high strength and can withstand certain vibrations and impacts, so it can be used as an installation structure for realizing the connection between the above assembly to be polished and the grinding equipment during the grinding process.

It should be noted that no matter how the reinforcement layer 400 is connected to the carrier sheet 100, it is necessary to ensure that the second surface 120 of the carrier sheet 100 is exposed, so that the second surface 120 can be used as a reference surface to contact the grinding equipment.

Step 5: Using the second surface 120 as the starting position for grinding, start grinding toward the chip 220 until the remaining thickness of the chip 220 meets the set thickness and then stop grinding. Specifically, the above-mentioned assembly to be polished is connected to the driving assembly of the grinding equipment through the reinforcing layer 400, so that the second surface 120 faces the grinding assembly of the grinding equipment, and then the position and posture of the assembly to be polished are adjusted so that the second surface 120 is aligned with the grinding assembly. The grinding surfaces of the grinding surfaces are kept parallel and attached to each other, and finally the grinding equipment is started, so that the grinding component rotates with respect to the component to be polished, so that grinding starts from the second surface 120, and as the grinding progresses, the thickness of the component to be polished decreases. Therefore, the driving assembly of the grinding equipment can also drive the assembly to be polished to feed towards the grinding assembly, so that the grinding surface is always in contact with the surface to be polished.

In some specific embodiments, the assembly to be polished jointly formed by the carrier sheet 100, the sample 200, the isolation layer 300 and the reinforcement layer 400 is a cylindrical structure, and the polishing assembly on the polishing equipment includes a clamping mechanism adapted to the cylinder.

The sample 200 after polishing is shown in the figure, wherein the carrier sheet 100, the frame 230, the backside part of the chip 220, the backside part of the isolation layer 300 and the backside part of the reinforcement layer 400 have all been removed by grinding, and the backside part of the chip 220 The remaining part is connected with the reinforcement layer 400 through the isolation layer 300 .

Step 6: According to the material of the isolation layer 300, select a corresponding method to remove the isolation layer 300, so that the chip 220 is separated from the reinforcement layer 400. So far, the chip 220 has been polished and can be separated from the reinforcement layer 400 for subsequent detection Work.

The grinding scheme of the present embodiment has the following advantages:

1. The back of the sample 200 is bonded to the first surface 110 of the carrier sheet 100 without any adhesive between them, so the sample 200 will not be skewed relative to the carrier sheet 100 due to uneven thickness of the adhesive. At the same time, the second surface 120 of the carrier sheet 100 is used as the reference plane to be attached to the grinding surface of the polishing equipment, so that the sample 200 and the carrier sheet 100 will not be skewed relative to the grinding surface, so that the chip 220 can have a uniform thickness after polishing.

Two, when adopting Fig. 1, when the mode shown in Fig. 2 is polished, the side of chip 220 is exposed outside, and in the process that chip 220 moves relative to the polishing device, except that the back side is polished, the side of chip 220 also can be polished, makes A chamfer 11 as shown in FIG. 5 is formed on the side of the bottom of the chip 220 . The chamfer 11 will cause reflection and refraction of infrared rays, resulting in unclear imaging. In this embodiment, an isolation layer 300 is coated on the outer surface of the chip 220 (including the aforementioned side), so that the isolation layer 300 can protect the bottom side of the chip 220 in addition to the role of isolating the chip 220 and the reinforcement layer 400. Avoid affecting the detection results due to chamfering 11.

Three, the present embodiment is also provided with an isolation layer 300, the isolation layer 300 is located between the chip 220 and the reinforcement layer 400, it can be removed from the chip 220 under set conditions, thereby realizing the separation of the chip 220 and the reinforcement layer 400, and Compared with the method in which the reinforcement layer 400 is directly connected to the chip 220 , the difficulty of separating the reinforcement layer 400 from the chip 220 can be significantly reduced, and residues on the chip 220 can also be avoided.

4. The present embodiment is also provided with a reinforced layer 400. Compared with the isolation layer 300, the reinforced layer 400 has higher strength and can withstand stronger vibration and impact. Therefore, the reinforced layer 400 is used to cover the isolation layer 300 to form a polished surface Components, and use the reinforcing layer 400 as a mounting component to install to the grinding equipment, compared with the solution of relying on the isolation layer 300 as the mounting component to install to the grinding equipment, it can reduce the probability of chipping and breaking of the component to be polished during the grinding process.

The second embodiment of the present invention also proposes another grinding method, which is also applicable to the sample 200 with the frame 230. The difference from the first embodiment is that the isolation layer 300 in this embodiment is not only coated In addition, it is also covered outside the frame 230 .

Referring to FIG. 6 , it shows a state change diagram of the sample 200 when polished by the polishing method according to the second embodiment of the present invention, including the following steps:

Step 1: Prepare the sample 200 from which the molding body 210 has been removed. The sample 200 includes the frame 230 and the chip 220 placed on the front side of the frame 230 .

Step 2: Place the sample 200 on the carrier sheet 100 so that the back of the frame 230 is attached to the first surface 110 of the carrier sheet 100 .

Step 3: Cover the outer surface of the chip 220 and the outer surface of the frame 230 with an isolation layer 300, and connect the isolation layer 300 to the first surface 110 of the carrier sheet 100, thereby connecting the chip 220, the frame 230 and the carrier sheet 100 together. The outer side of the frame 230 referred to here refers to other surfaces except the back side of the frame 230 and the bonding area between the front side of the frame 230 and the chip 220 .

Step 4: Coating the reinforcement layer 400 on the outer side of the isolation layer 300 and exposing the second surface 120 as a reference surface to contact with the grinding equipment.

Step 5: Using the second surface 120 as the starting position for grinding, start grinding toward the chip 220 until the remaining thickness of the chip 220 meets the set thickness and then stop grinding.

Step 6: According to the material of the isolation layer 300, select a corresponding method to remove the isolation layer 300, so that the chip 220 is separated from the reinforcement layer 400. So far, the chip 220 has been polished and separated from the reinforcement layer 400 to allow subsequent detection Work.

In addition to the advantages of the first embodiment, the grinding scheme of this embodiment also has the following advantages:

1. Generally, the area of the frame 230 beyond the chip 220 is not too large. If the frame of the sample itself is used as the reference plane for subsequent polishing, the isolation layer 300 needs to be limited within the frame 230 to prevent the isolation layer from overflowing to the back of the frame. Affects the horizontality of the sample grinding reference plane, but this operation is more difficult, and the area of the carrier sheet 100 is not limited, and can be set larger, so the isolation layer 300 covers the chip 220 and the frame 230 at the same time, which is easier to operate.

2. The sample 200 and the carrier sheet 100 are pre-fixed by the isolation layer 300 , which can prevent the sample 200 and the carrier sheet 100 from moving during the process of wrapping the reinforcing layer 400 .

As an improvement of the second embodiment above, the isolation layer 300 is made of a material with hot-melt properties, so that the isolation layer 300 can be formed by heating first and then curing. Referring to FIG. 7 , the method for setting the isolation layer 300 in this embodiment includes :

Step 1: After the sample 200 is placed on the carrier sheet 100 , a solid isolation material is applied on top of the chip 220 .

Step 2: heating the isolation material to melt the isolation material and flow down to the first surface 110 of the carrier sheet 100 to cover the chip 220 and the frame 230 . In some specific embodiments, the insulation material can be heated by the heating device 500, the heating device 500 can be a heating table with a horizontal heating surface in the figure, the second surface 120 of the carrier sheet 100 is attached to the heating surface, when the heating table starts, The heat is transferred to the insulating material through the carrier sheet 100 and the sample 200 .

Step 3: solidify the molten isolation material to form the isolation layer 300 . For example, the heating device 500 can be turned off to make the isolation material solidify by itself, or it can be accelerated by an external cooling device.

In the above embodiment, the melted flow of the isolation material is used to automatically cover the chip 220 and the frame 230 , and the experimenter does not need to perform other operations, which helps to simplify the process.

In some specific embodiments, the material of the isolation layer 300 is paraffin wax, which is solid at room temperature, can melt after heating, and can re-solidify after cooling, so it can meet the aforementioned requirements of automatic flow when heated and solidification after cooling. On the other hand, the paraffin can be dissolved in acetone to realize the removal of the isolation layer 300 without damaging the chip 220 during the removal process. After the paraffin is dissolved, the chip 220 will be separated from the reinforcing layer 400 automatically.

In this example, the heating temperature of the paraffin wax is 100°C to 105°C. After verification by the inventors, the paraffin wax has a certain fluidity within this temperature range, but the fluidity is not too strong, so it can be gathered to form a wax similar to that shown in Figure 7. The shown hemispherical structure makes the isolation layer 300 maintain a certain thickness to play a corresponding isolation function.

The third embodiment of the present invention also proposes another grinding method, which is also applicable to the sample 200 with the frame 230. The difference from the first embodiment is that the reinforcement layer 400 in this embodiment is not only coated 300 , it is also coated on other surfaces of the carrier sheet 100 except the second surface 120 .

Referring to FIG. 8 , it shows a state change diagram of the sample 200 when the grinding method according to the third embodiment of the present invention is polished, including the following steps:

Step 1: Prepare the sample 200 from which the molding body 210 has been removed. The sample 200 includes the frame 230 and the chip 220 placed on the front side of the frame 230 .

Step 2: Place the sample 200 on the carrier sheet 100 so that the back of the frame 230 is attached to the first surface 110 of the carrier sheet 100 .

Step 3: coating the outer surface of the chip 220 with the isolation layer 300 .

Step 4: Cover the outer surface of the isolation layer 300 and the outer surface of the carrier sheet 100 except the second surface 120 with the reinforcement layer 400 , and expose the second surface 120 as a reference surface to contact with the grinding equipment.

Step 5: Using the second surface 120 as the starting position for grinding, start grinding toward the chip 220 until the remaining thickness of the chip 220 meets the set thickness and then stop grinding.

Step 6: According to the material of the isolation layer 300, select a corresponding method to remove the isolation layer 300, so that the chip 220 is separated from the reinforcement layer 400. So far, the chip 220 has been polished and separated from the reinforcement layer 400 to allow subsequent detection Work.

In addition to the advantages of the first embodiment, the grinding scheme of this embodiment also has the following advantages: the carrier sheet 100 is embedded in the reinforcement layer 400, which can increase the connection strength between the carrier sheet 100 and the reinforcement layer 400, avoiding During the grinding process, the carrier sheet 100 is detached from the reinforcing layer 400 .

As an improvement of the third embodiment above, referring to FIG. 9 , the method for setting the enhancement layer 400 in this embodiment includes the following steps:

Step 1: Set up a mold 600 with a cavity 610, the bottom of the mold 600 is closed, and the top has an opening. The carrier sheet 100 carrying the sample 200 is placed in the mold 600 so that the second surface 120 is attached to the bottom wall of the accommodating cavity 610 .

Step 2: Add liquid reinforcement material into the accommodation chamber 610 , the liquid reinforcement material can automatically fill the accommodation chamber 610 until the liquid level is higher than the isolation layer 300 .

Step 3: After the liquid reinforcement material is solidified to form the reinforcement layer 400 , the reinforcement layer 400 is separated from the mold 600 .

In the above embodiment, the second surface 120 is covered by the bottom wall of the accommodating cavity 610, which can prevent the second surface 120 from adhering to the reinforcement material. In addition, the reinforcement layer 400 is arranged flush with the second surface 120, so that the second surface 120 can be used as a reference plane. for sanding.

In some specific embodiments, the material of the reinforcing layer 400 is resin, which has higher strength than paraffin and can resist shock and vibration during polishing.

It should be noted that the above-mentioned second embodiment to the third embodiment can be combined. Referring to FIG. The outer side of the isolation layer 300 and other surfaces of the carrier sheet 100 except the second surface 120 have the advantages of the above-mentioned first embodiment to the third embodiment.

The fourth embodiment of the present invention also proposes another polishing method, which differs from the first to third embodiments in that this embodiment is suitable for direct polishing of the chip 220, that is, the incoming material of the sample 200 is bare chip, so the previous step of removing the molding body 210 is not required.

Referring to FIG. 11 , it shows a state change diagram of the sample 200 when polished by the polishing method of the fifth embodiment of the present invention, including the following steps:

Step 1: Prepare the chip 220 to be polished.

Step 2: Place the chip 220 directly on the carrier sheet 100 so that the back of the chip 220 is attached to the first surface 110 of the carrier sheet 100 .

Step 3: Cover the outer surface of the chip 220 with an isolation layer 300 , and the isolation layer 300 is connected to the first surface 110 of the carrier sheet 100 , thereby connecting the chip 220 and the carrier sheet 100 together.

Step 4: Coating the reinforcement layer 400 on the outer side of the isolation layer 300, the reinforcement layer 400 is connected to the first surface 110 of the carrier sheet 100, and the second surface 120 of the carrier sheet 100 is exposed to be in contact with the grinding equipment as a reference surface.

Step 5: Using the second surface 120 as the starting position for grinding, start grinding toward the chip 220 until the remaining thickness of the chip 220 meets the set thickness and then stop grinding.

Step 6: According to the material of the isolation layer 300, select a corresponding method to remove the isolation layer 300, so that the chip 220 is separated from the reinforcement layer 400. So far, the chip 220 has been polished and separated from the reinforcement layer 400 to allow subsequent detection Work.

In addition to the advantages of the first embodiment, the grinding scheme of this embodiment does not need to remove the frame 230 through grinding, so the workload of grinding can be reduced.

The sixth embodiment of the present invention also proposes another grinding method, which differs from the first to third embodiments in that this embodiment is suitable for direct grinding of a sample 200 with a molded body 210, for example, a sample The incoming material 200 is a complete power module, and the previous step of removing the molding body 210 is not required.

Referring to FIG. 12 , it shows a state change diagram of the sample 200 when the polishing method according to the fifth embodiment of the present invention is polished, including the following steps:

Step 1: Prepare the sample 200 to be polished. The sample 200 includes a molded body 210 , a chip 220 and a frame 230 inside the molded body 210 , and the chip 220 is placed on the front of the frame 230 .

Step 2: Place the sample 200 on the carrier sheet 100 so that the back of the sample 200 is attached to the first surface 110 of the carrier sheet 100 .

Step 3: Cover the outer surface of the sample 200 with an isolation layer 300 , and the isolation layer 300 is connected to the first surface 110 of the carrier sheet 100 , thereby connecting the sample 200 and the carrier sheet 100 together.

Step 4: Coating the reinforcement layer 400 on the outer side of the isolation layer 300, the reinforcement layer 400 is connected to the first surface 110 of the carrier sheet 100, and the second surface 120 of the carrier sheet 100 is exposed to be in contact with the grinding equipment as a reference surface.

Step 5: Using the second surface 120 as the starting position for grinding, start grinding toward the chip 220 until the remaining thickness of the chip 220 meets the set thickness and then stop grinding.

Step 6: According to the material of the isolation layer 300, select a corresponding method to remove the isolation layer 300, so that the chip 220 is separated from the reinforcement layer 400. So far, the chip 220 has been polished and separated from the reinforcement layer 400 to allow subsequent detection Work.

It should be noted that, in the above-mentioned embodiments, the polishing of the sample 200 or the chip 220 is completed by sandpaper, specifically, the carrier sheet 100, the frame 230 and the chip 220 are respectively polished by sandpaper with a gradually increasing mesh number, wherein the mesh number of the sandpaper is The lower the value, the greater the removal amount of a single friction, the faster the grinding speed, the rougher the grinding surface, the higher the mesh number of the sandpaper, the smaller the removal amount of a single friction, the slower the grinding speed, and the smoother the grinding surface. Based on the above, when grinding the carrier sheet 100, because it is far away from the chip 220, sandpaper with a lower mesh number can be used for quick grinding; Grinding with relatively high sandpaper, under the premise of ensuring a certain grinding speed, can avoid damage to the chip 220 when it is polished close to the chip 220; Grinding quality. By using different sandpapers for grinding at different stages, both the grinding speed and the grinding quality can be considered.

For example, when polishing the carrier sheet 100 , 180 mesh sandpaper can be used, when polishing the frame 230 , 400 mesh sandpaper can be used, and when polishing the chip 220 , 800 mesh sandpaper can be used.

It should be noted that the grinding stage can be judged according to the polished thickness or visual observation.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments. Within the scope of knowledge of those skilled in the art, various modifications can be made without departing from the spirit of the present invention. Variety. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other if there is no conflict.

Claims (10)

1. chip polishing method, is characterized in that, comprises the following steps: Prepare a sample to be processed and a hard carrier sheet, the sample includes a chip and a frame, the chip is connected to the front of the frame, and the carrier sheet has a first surface and a second surface oppositely arranged; bonding the back of the frame to the first surface of the carrier sheet; Coating an isolation layer at least on the outer side of the chip, and coating a reinforcing layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet; Grinding the chip from the second surface until the chip has a predetermined remaining thickness; The isolation layer is removed to separate the sample from the reinforcement layer. 2. The chip polishing method according to claim 1, characterized in that, the isolation layer is made to cover other outer surfaces of the frame except the back surface, and the isolation layer and the carrier sheet are first surface connection. 3. The chip polishing method according to claim 2, wherein the method for setting the isolation layer comprises: applying a solid isolation material on top of the chip after the sample is placed on the carrier; heating the isolation material to melt the isolation material and flow down to the carrier sheet to cover the chip and the frame; The molten barrier material is solidified to form the barrier layer. 4 . The chip polishing method according to claim 3 , wherein the isolation layer is made of paraffin wax, and the heating temperature is 100° C. to 105° C. 4 . 5 . The chip grinding method according to claim 1 , wherein the reinforcing layer is made to cover other outer surfaces of the carrier sheet except the second surface. 6 . 6. The chip polishing method according to claim 5, characterized in that, the method for setting the reinforcement layer comprises: setting a mold with an accommodating cavity, placing the carrying sheet carrying the sample in the mold, and making the second surface fit the bottom wall of the accommodating cavity; Adding a liquid reinforcement material into the accommodating cavity until the liquid level is higher than the isolation layer; The reinforcing material in a liquid state is cured to form the reinforcing layer. 7. The chip polishing method according to claim 6, characterized in that, the material of the reinforcing layer is resin. 8 . The chip polishing method according to claim 1 , wherein the carrier sheet, the frame, and the chip are respectively polished with sandpaper of increasing mesh number. 9 . 9. The chip polishing method is characterized in that, comprising the following steps: preparing a carrier sheet and chips to be processed, the carrier sheet has a first surface and a second surface oppositely arranged; bonding the back of the chip to the first surface of the carrier sheet; Coating an isolation layer on the outer side of the chip, and coating a reinforcement layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet; Grinding starts from the second surface until the chip reaches a set thickness; The isolation layer is removed to separate the chip from the reinforcement layer. 10. The chip polishing method is characterized in that, comprising the following steps: Prepare a carrier sheet and a sample to be processed, the sample includes a molded body, and a chip and a frame located in the molded body, the chip is connected to the front of the frame, and the carrier sheet has a first surface and second surface; bonding the back side of the molding body to the first surface of the carrier sheet; Coating an isolation layer on the outer side of the molded body, and coating a reinforcement layer on the outer side of the isolation layer, and exposing at least the second surface of the carrier sheet; Grinding the chip from the second surface until the chip has a predetermined remaining thickness; The isolation layer is removed to separate the sample from the reinforcement layer.

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