JPH06312510A - Inkjet recording head manufacturing method - Google Patents

Abstract

(57) [Summary] [Structure] An inkjet recording head manufacturing method based on the present invention comprises a step of forming a plurality of films on an element for generating energy used for ejecting ink,
It is a photolithography process which is roughly composed of a step of applying a resist to the film obtained by this step and a step of removing the applied resist, and the residue of the resist not removed by the step of removing the resist. Are removed by O ₂ ashing, and further O ₂
After ashing, sputter etching is performed. EFFECT resist residues by O ₂ ashing is removed, also the contamination of adhesion deterioration and impurity of the Ti film and the SiO ₂ film to oxidation and due to this the Ti surface layer by O ₂ ashing is improved by sputter etching .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an ink jet type recording head, particularly a bubble jet type recording head.

[0002]

2. Description of the Related Art In recent years, the discovery of the bubble jet method has enabled high quality recording. The valve jet method can achieve high density of nozzles because (i) the recording head can be manufactured by applying semiconductor manufacturing technology, and (ii) the noise during recording is low because it is a non-impact method.
(iii) Since the ink is ejected onto a recording medium (paper, cloth, plastic sheet, etc.) with high accuracy, high quality color recording is easy.

FIG. 6 is a side sectional view of a conventional bubble jet recording head. The schematic structure of the heating element provided in the recording head will be described with reference to this drawing. Reference numeral 1 is a substrate (heating element) on which a heating element is installed, 2 is a liquid chamber, 3 is a top plate, and 4 is a discharge orifice. The heating element 1 includes a heat storage layer 6, a heating resistor 7, electrodes 8 on a substrate 5,
The insulating protection film 9 and the anti-cavitation film 10 are placed in the liquid chamber 2.
It is laminated toward the side. Heating surface (heating element)
Reference numeral 11 is a region on the heating resistor 7 that is not covered by the electrode 8. The materials used for each component will be described. In general, the substrate 5 is Si (silicon) with good heat dissipation.
A substrate is used, and by covering the surface of the substrate 5 with a SiO ₂ (silicon oxide) oxide film as a heat insulating material, a heat storage layer 6 is formed and a large amount of heat is applied to the ink side. . Since the heating resistor 7 is required to withstand high heat, HfB ₂ (hafnium boride), which is a high melting point material, is used.
Is used, and Al (aluminum) is used for the electrode 8. Then, an insulating protective layer 9 and a cavitation resistant film 10 made of SiO ₂ and Ta (tantalum) having a thickness of several μm are formed thereon. The SiO ₂ plays a role of preventing the contact between the electrode / heater and the ink and preventing the oxidation, and the Ta layer plays a role of protecting the heater from mechanical damage (cavitation destruction) which occurs at the same time as the bubble is defoamed. Cavitation fracture is a wear fracture that occurs when a material is repeatedly struck by the high pressure that occurs when bubbles collapse. The structure as described above is formed on the substrate with accuracy of several μm or less by using the photolithography process. When a signal is externally applied to the electrode 8, the heating element 11 generates heat. The ink in the vicinity of the heating element 11 is instantly heated to generate bubbles, and the ink droplets 12 are ejected from the ejection orifice 4 by utilizing the pressure generated by the bubbles.

The life of the recording head depends on the life of the heating resistor 7, and the breaking of the resistor 7 extends the life of the head. In particular, if there is a foreign substance on the heating element 11, the coverage of the protective layer becomes insufficient and cavitation damage is likely to occur, which causes an early disconnection. Most of the foreign matter on the heating element is the rest of the resist in the photolithography process. Regarding such foreign matter, there is a case where the foreign matter is contaminated in the protective film, or the foreign matter remains on the heating element before the protective film is formed. Since the occurrence rate of such contamination is very low, it is not a factor that lowers the yield in the manufacturing process of the serial head in which the total number of nozzles is about 100, but it is a full multi head in which the total number of nozzles is 1000 or more. In the manufacturing process of 1), it becomes a factor that greatly reduces the yield. Therefore, some attempts have been made to remove such foreign matter. Wet peeling is known as a method thereof.

[0005]

However, in the wet stripping process for removing the unnecessary resist film from the substrate, it is difficult to control stripping solution, cleaning water, etc. There was a problem that the resist remained in some places without being completely removed. Moreover, once the resist is dried, it cannot be removed by subsequent substrate cleaning.
Further, there is a method (O ₂ ashing) of removing the resist on the substrate in the vapor phase in order to solve such a problem, but a new problem occurs that the surface of the heating element is oxidized. Oxidation of the heating element surface sometimes lowers the adhesion between the heating element and the protective layer and makes the temperature distribution uneven when heating the heating element. Is known to be. Therefore,
The object of the present invention is to completely remove the resist residue on the heating element generated in the photolithography process, and the adhesiveness between the heating element and the protective layer is significantly improved compared to the conventional one, and the durability is high and the manufacturing yield is high. To provide a low cost bubble jet and recording head for a thermal electrostatic inkjet printer.

[0006]

In order to solve the above-mentioned problems, in the present invention, a step of forming a plurality of films on an element that generates energy used for ejecting ink, and by this step, In the method for manufacturing an ink jet recording head, which is manufactured by a photolithography process that is roughly composed of a step of applying a resist to the obtained film and a step of removing the applied resist, it is not removed by the step of removing the resist resist of the residue is removed by O ₂ ashing, further O ₂
It is characterized in that sputter etching is performed after ashing. Further, preferably, the element that generates energy used for ejecting the ink is an electrothermal converter that generates thermal energy that causes film boiling in the ink.

[0007]

The method of manufacturing a recording head according to the present invention is based on O ₂
The resist residue is removed by ashing, and the oxidation of the Ti surface layer by O ₂ ashing and the resulting decrease in adhesion between the Ti film and the SiO ₂ film and contamination of impurities are improved by sputter etching.

[0008]

EXAMPLE An example of a method of manufacturing a recording head according to the present invention will be described below. The heating element (electrothermal converter) of the recording head is manufactured by the following steps (1) to (8). (1) As a pre-stage of photolithography, as shown in FIG. 1, H as the heating resistors 7 and 7'on the Si substrate 6
A fB ₂ film is formed in a thickness of 1000Å, a Ti film is formed in a film thickness of 100Å, and an Al film is formed to have an Al film thickness of 4500Å (FIG. 1).

(2) Pattern Al, Ti and HfB ₂ (FIG. 2).

(3) After applying a resist to the wiring portion excluding the portion to be the heating element, Al on the heating element is etched (FIGS. 3 and 4).

(4) Al, Ti and Hf are applied after the resist 13 is applied to the wiring portion in order to cut shorts between the wirings.
Etching is performed according to the pattern of B ₂ .

(5) The resist is wet-peeled off.

(6) The resist residue is ashed (O ₂ ashing) in an oxygen plasma by high frequency discharge.

(7) Etching (sputter etching) by a sputtering effect of inert gas ions (Ar plasma) used for pretreatment of metal deposition and flattening of convex portions.

(8) A SiO ₂ film is formed as the insulating protection layer 9 (FIG. 5).

[0016] In this manufacturing method, resist residue is removed by O ₂ ashing, also Ti film and SiO caused oxidation and to the Ti surface layer by O ₂ ashing
_The decrease in adhesion to the _two films and the contamination of impurities are improved by the sputter etching. Therefore, the number of foreign substances on the heating element of the heating element created by this manufacturing method is
It was about 1/3 of the case of the conventional manufacturing method (the yield was tripled). Further, it was confirmed that the durability of the recording head having the heating element produced by this manufacturing method is not different from that of the recording head based on the conventional manufacturing method (data not shown).

It should be noted that the wet peeling in the above-mentioned step (5) should be O
It can be ₂ ashing.

(Others) In particular, the present invention is provided with a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for ejecting ink, particularly in the ink jet recording system. The present invention brings about excellent effects in a recording head and a recording apparatus of the type in which the state of ink is changed by the heat energy. This is because such a system can achieve high density recording and high definition recording.

Regarding the typical structure and principle thereof, see, for example, US Pat. No. 4,723,129 and US Pat. No. 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
Although it can be applied to any of the continuous type, in particular, in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. Liquid (ink) corresponding to this drive signal in a one-to-one correspondence
It is effective because bubbles can be formed inside. Due to the growth and contraction of the bubbles, the liquid (ink) is ejected through the ejection opening to form at least one droplet. It is more preferable to make this drive signal into a pulse shape because bubbles can be immediately and appropriately grown and contracted, so that liquid (ink) ejection with excellent responsiveness can be achieved. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, further excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angle liquid passage) as disclosed in the above-mentioned respective specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
The structure using the specification of No. 59600 is also included in the present invention. In addition, Japanese Unexamined Patent Publication No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy is provided. The effect of the present invention is effective even if the configuration corresponding to the ejection portion is disclosed in JP-A-59-138461. That is, according to the present invention, recording can be surely and efficiently performed regardless of the form of the recording head.

Further, the present invention can be effectively applied to a full-line type recording head having a length corresponding to the maximum width of a recording medium which can be recorded by the recording apparatus. Such a recording head may have a configuration that satisfies the length by a combination of a plurality of recording heads or a configuration as one recording head integrally formed.

In addition, even in the case of the serial type as in the above example, the recording head fixed to the apparatus main body or the electrical connection with the apparatus main body and the ink from the apparatus main body by being attached to the apparatus main body The present invention is also effective when a replaceable chip-type recording head that can be supplied or a cartridge-type recording head in which an ink tank is integrally provided in the recording head itself is used.

Further, as the constitution of the recording apparatus of the present invention, it is preferable to add an ejection recovery means of the recording head, a preliminary auxiliary means and the like because the effect of the present invention can be further stabilized. Specifically, heating is performed by using a capping unit, a cleaning unit, a pressure or suction unit for the recording head, an electrothermal converter or a heating element other than this, or a combination thereof. Examples thereof include a preliminary heating unit for performing the discharge and a preliminary discharge unit for performing discharge different from the recording.

Regarding the type and number of recording heads to be mounted, for example, only one is provided corresponding to a single color ink, or a plurality of inks having different recording colors and densities are supported. A plurality of pieces may be provided. That is, for example, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but it may be either the recording head is integrally formed or a plurality of combinations may be used. The present invention is also extremely effective for an apparatus provided with at least one of full-color recording modes by color mixing.

In addition, in the above-described embodiments of the present invention, the ink is described as a liquid, but an ink that solidifies at room temperature or lower and that softens or liquefies at room temperature may be used. Or, in the inkjet system, it is common to control the temperature of the ink itself within the range of 30 ° C. or higher and 70 ° C. or lower to control the temperature so that the viscosity of the ink is within the stable ejection range. Sometimes, a liquid ink may be used. In addition, the temperature rise due to thermal energy is positively prevented by using it as the energy of the state change from the solid state of the ink to the liquid state, or in order to prevent the evaporation of the ink, it is solidified and heated in the standing state. You may use the ink liquefied by. In any case, by applying heat energy such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In this case, the ink is
JP-A-54-56847 or JP-A-60-7
As described in Japanese Patent No. 1260, it may be configured to face the electrothermal converter in a state of being held as a liquid or a solid in the concave portion or the through hole of the porous sheet. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the ink jet recording apparatus of the present invention, besides the one used as an image output terminal of an information processing apparatus such as a computer, a copying apparatus combined with a reader or the like, and a facsimile apparatus having a transmission / reception function. It may be a form or the like.

[0027]

According to the method of manufacturing an ink jet recording head according to the present invention, a step of forming a plurality of films on an element for generating energy used for ejecting ink, and a step obtained by this step. By a photolithography process which is roughly composed of a step of applying a resist to the film and a step of removing the applied resist, the residue of the resist not removed by the step of removing the resist is removed by O ₂ ashing. Furthermore, after the O ₂ ashing, sputter etching is performed. Preferably, the element that generates energy used for ejecting ink is an electrothermal converter that generates thermal energy that causes film boiling in the ink. since those with, resist residue is removed by O ₂ ashing, and O ₂ ashing Ti film and contamination of adhesion deterioration and impurity of the SiO ₂ film to oxidation and due to this the Ti surface layer with is improved by sputter etching, high durability and production yield is high inexpensive bubble jet and Netsusei It is possible to provide a recording head for an electric inkjet printer.

[Brief description of drawings]

FIG. 1 is a view for explaining a film forming process constituting an ink jet recording head manufacturing method according to the present invention,
(A) is a sectional view and (b) is a plan view.

2A and 2B are views for explaining a patterning process constituting an inkjet recording head manufacturing method according to the present invention, in which FIG. 2A is a sectional view and FIG. 2B is a plan view.

3A and 3B are views for explaining a resist coating step which constitutes an inkjet recording head manufacturing method according to the present invention, in which FIG. 3A is a sectional view and FIG. 3B is a plan view.

FIG. 4 is a sectional view and (b) is a plan view for explaining an etching step constituting a method for manufacturing an ink jet recording head according to the present invention.

5A and 5B are views for explaining a SiO ₂ film forming step which constitutes an inkjet recording head manufacturing method according to the present invention, in which FIG. 5A is a sectional view and FIG. 5B is a plan view.

FIG. 6 is a side view of a conventional bubble jet recording head.

[Explanation of symbols]

 1 Substrate on which a heating element is installed (heating element) 2 Liquid chamber 3 Top plate 4 Discharge orifice 5 Substrate 6 Heat storage layer 7 Heating resistor 8 Electrode 9 Insulation protection layer 10 Cavitation resistant film 11 Heating surface (heating element) 12 Ink droplets 13 Resist

Claims (2)

[Claims] 1. A step of forming a plurality of films on an element that generates energy used for ejecting ink,
In a method for manufacturing an ink jet recording head, which is manufactured by a photolithography process that is roughly composed of a step of applying a resist to the film formation and a step of removing the resist, the resist not removed by the step of removing the resist Was removed by O ₂ ashing,
Furthermore, after the O ₂ ashing, sputter etching is performed, and the method of manufacturing an ink jet recording head. 2. The method for manufacturing an ink jet recording head according to claim 1, wherein the element is an electrothermal converter that generates thermal energy that causes film boiling in the ink.