JP2006224591A - Method for manufacturing inkjet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form an etching sacrificial layer and wiring by the same process by making the etching sacrificial layer to be a two-layer constitution consisting of a thin heater layer and a wiring layer, to achieve remarkably simplification of the process, to shorten the process of CRBTJ manufacturing method, and to improve reliability. <P>SOLUTION: The sacrificial layer is made to be a three-layer constitution of wiring/heater/wiring, to be able to form an ink feeding hole prepared by vertically etching a Si(110) substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inkjet recording head that discharges a desired liquid by applying energy to the liquid from the outside, and a method for manufacturing the inkjet recording head.

  There is known an ink jet recording method in which the generation of bubbles is promoted by applying energy such as heat to the ink, the ink is ejected from the ejection port using this volume change, and this is deposited on the recording medium to form an image. It has been. Among ink jet systems, a side shooter type (Japanese Patent Laid-Open No. 9-011479) that ejects ink perpendicular to a substrate has been proposed. Further, as a method of manufacturing this head, a method (Japanese Patent Laid-Open No. 10-181032) for forming the shape of an ink supply port using an etching sacrificial layer is disclosed.

This is a material in which a silicon oxide film or a silicon nitride film is formed on a silicon substrate, an ink discharge pressure generating element is formed on the silicon oxide film or the silicon nitride film, and the silicon substrate surface is easily affected by an etching solution. Depositing a thin film to form a pattern (etching sacrificial layer) in the shape of an ink supply port, further forming an etching stop layer on the pattern in the shape of the supply port, and forming an ink discharge port on the surface of the silicon substrate; An opening is provided on the back surface of the silicon oxide film or silicon nitride film forming surface, and the silicon serving as the ink supply port is removed by anisotropic etching, and the silicon oxide film of the etching stop layer remaining in the ink supply port or It has been formed by a process of removing the silicon nitride film or a mixture thereof.
Japanese Patent Laid-Open No. 9-11479 Japanese Patent Laid-Open No. 10-181032

  In the conventional side shooter type ink jet recording head, as shown in JP-A-10-181032, the etching sacrificial layer has a single layer structure using polysilicon or Al alloy. In this case, since the structure of the etching sacrificial layer is different from that of other layers such as wiring, there is a problem that the number of processes increases, for example, a process for forming the etching sacrificial layer is specially provided.

  The above-mentioned problems include a step of forming an insulating film such as a silicon oxide film or a silicon nitride film as a livestock heat layer on a silicon substrate, a step of forming an ink discharge pressure generating element on the film, a surface of the silicon substrate Forming a pattern (etching sacrificial layer) in the shape of the ink supply port, and forming a silicon oxide film, a silicon nitride film or a mixture thereof on the pattern in the shape of the supply port A step of forming an etching stop layer, a step of providing an opening on the back surface on which the silicon oxide film or the silicon nitride film is formed, and removing silicon in a portion serving as an ink supply port by anisotropic etching; The process for removing the remaining silicon oxide film, silicon nitride film or mixture of the etching stop layer is reduced. A method of manufacturing an inkjet recording head including at least a thin film pattern (etching sacrificial layer) in the shape of a supply port on the substrate surface, wherein three layers of different materials are laminated. It is solved by the method of manufacturing the head.

(Function)
The heater wiring for generating ink discharge pressure has a three-layer structure consisting of a high resistance layer and a low resistance layer, and the heater section is formed by etching a part of the low resistance wiring to expose the high resistance section layer. In the case of employing the same, the etching sacrificial layer having a similar three-layer structure can be formed simultaneously with the heater wiring for generating the ink discharge pressure, thereby simplifying the process.

  When the etching sacrificial layer is formed as a two-layer structure with the lower layer as a heater and the upper layer as a wiring, the etching capability is insufficient as described in the following experiment, and it is applicable to open an ink supply port perpendicular to the Si (110) wafer. Can not.

  As described above, according to the present invention, the sacrificial layer and the wiring can be formed in the same process by making the etching sacrificial layer into a two-layer structure of the thin heater layer and the wiring layer, and the process can be greatly improved. Simplification was achieved. In addition, the reliability of the wiring process has been improved.

[Experiment 1]
Hereinafter, experiments related to the present invention will be described. FIG. 3 shows a cross-sectional structure of a sample used in the experiment. An AlCu film (Al: Cu = 99.5: 0.5) 1000 Å and a TaSiN film (Ta: Si: N = 43: 42: 15) are formed on the surface of a Si (110) wafer 101 having a diameter of 5 inches and a thickness of 625 μm. A sacrificial layer 102 was formed by depositing 2000 to 1000 layers of 200 to 1000 ２００ AlCu films (Al: Cu = 99.5: 0.5) and patterning them as shown in FIG. The shape of the sacrificial layer was a parallelogram with a narrow angle of 70.5 degrees, and the long side was parallel to the (110) orientation of the Si substrate. The size was 160 μm wide and 8 mm long. An etching stop layer 103 was formed by depositing 8000 mm of SiN film by plasma CVD thereon. The deposition conditions of the SiN film at this time were SiH ₄ / NH ₃ / N ₂ = 500/1500/6300 sccm, pressure 150 mtorr, substrate temperature 380 ° C., and RF 1700 W. On the back surface of the substrate, an anisotropic etching pattern is formed by patterning a thermal oxide film as shown in the plan view of FIG. This is a mirror image relationship with the sacrificial layer on the surface. In the opening of the oxide film on the back surface, an etching lead hole 105 that does not penetrate the substrate is processed in the vicinity of the narrow angle of the parallelogram. An alkali resistant resist (OBC, manufactured by Tokyo Ohka Kogyo) 106 is applied to the substrate surface.

A plurality of samples in which the thickness of the TaSiN film as an intermediate layer of the sacrificial layer was changed from 200 to 2000 mm were immersed in tetramethylammonium hydride (TMAH), and silicon was anisotropically etched from the back surface. Etching conditions were TMAH / H ₂ O = 21%, liquid temperature 83 ° C., and etching time was 7 hours.

  When the thickness of the TaSiN film is in the range of 200 to 1000 mm, the hole opened in the silicon reaches the sacrificial layer as shown in FIG. 4, the sacrificial layer is etched and stopped at the etching stop layer, and the remaining sacrificial layer is not observed. . When the thickness of the TaSiN film was 1000 mm or more, a sacrificial layer residue was generated.

[Experiment 2]
As a comparative experiment, the sacrificial layer has a two-layer structure in which the thickness of the TaSiN film is 500 mm and the upper AlCu layer is 2000 mm as shown in FIG. Anisotropic etching was performed. Then, as shown in FIG. 11, a sacrificial layer residue was generated in the vicinity of the narrow angle of the sacrificial layer from 150 to 250 μm from the narrow angle.

[Experiment 3]
In the same configuration as in Experiment 1, the thickness of the intermediate TaSiN film was fixed to 500 mm, the upper AlCu layer was fixed to 2000 mm, and the lower AlCu film thickness was changed from 200 to 8000 mm, Similarly, anisotropic etching was performed. The sacrificial layer was all etched when the AlCu film thickness was 300 mm or more, but a sacrificial layer that was not etched partially remained below that thickness. When the sacrificial layer was 7000 mm or more, cracks in the etching stop layer were observed after etching in some samples.

[Experiment 4]
As a comparative experiment, as shown in FIG. 8, a sacrificial layer was formed as one layer, and a sample similar to that in Experiment 1 was prepared, and anisotropic etching was performed. At this time, if the thickness of the AlCu sacrificial layer was thin, an etching residue was generated near the narrow angle of the sacrificial layer pattern as shown in FIG. FIG. 12 shows the relationship between the thickness of the sacrificial layer and the length X from the narrow angle of the remaining portion of the sacrificial layer. It can be seen that when the thickness of the sacrificial layer is 400 mm or less, the remaining sacrificial layer increases rapidly.

[Example Embodiment]
FIG. 1 is a schematic view of a heater board substrate in the process of manufacturing an ink jet recording head showing an embodiment according to the present invention. A (110) Si wafer 201 is used as the substrate. Three layers of wiring layer 203 / heater layer 204 / wiring layer 205 were deposited on the surface of the wafer, deposited, and patterned to form a sacrificial layer 207. The planar shape of the sacrificial layer is a parallelogram with a narrow angle of 70.5 degrees. The thickness of the sacrificial heater layer is generally 800 mm or less, preferably 700 mm, and optimally 600 mm or less. On the other hand, the thickness of the wiring layer below the sacrificial layer is generally 300 to 7000, preferably 400 to 6000 mm, and most preferably 500 to 5000 mm.

  A thin film was deposited thereon by sputtering, vapor deposition, or plasma CVD to form an etching stop layer 304. The thickness of the etching stop layer is generally 1000 to 20000 mm, preferably 2000 to 16000 mm, and most preferably 3000 to 13000 mm.

  A pattern in which a heater layer and a wiring layer are laminated is disposed adjacent to the sacrificial layer. The heater layer 208 is formed by etching the wiring layer with a part of the pattern.

  An ink supply port opening 211 is formed on the back surface of the substrate by patterning an alkali-resistant film. An ink supply port is then opened by anisotropic etching from the surface toward the sacrificial layer on the surface. Form.

  Next, the process of the ink jet recording nozzle according to the present invention will be described step by step with reference to FIG.

  (1) An insulating film 302 is formed on a silicon substrate 301 having a substrate surface orientation (110) of, for example, thermal oxidation or CVD, and a desired pattern 303 for providing an ink supply port as shown in FIG. 10 is formed by photolithography. Form.

  (2) A metal having a low resistance such as Al or Cu suitable for a wiring material and a high etching rate with respect to an etchant for anisotropic etching such as TMAH (tetra-methyl-ammonium hydride) is deposited and patterned. 304 and a sacrificial layer 305 are formed. The etching sacrificial layer is an etching rate that is much faster than the Si wafer when etching proceeds from the back surface and the etchant reaches the sacrificial layer, so that etching can be performed in a short time and an opening corresponding to the sacrificial layer pattern can be opened. is there. The pattern at this time is a parallelogram with a narrow angle of 70.5 degrees as shown in FIG. 5 so that an etching hole is perpendicular to the substrate. The long side and the short side of the parallelogram are (111) To be parallel to the equivalent plane. The wiring material at the position where the heater portion is formed is removed by etching in advance as in 306.

  (3) A heater material 307 having high resistance and a low resistance material for wiring 308 are continuously deposited, and a part of the upper wiring material is also removed by etching to form a heater portion 309.

  (4) An SiN or SiON film is deposited as an etching stop layer 310 on the substrate surface by plasma CVD. As the etching stop layer, two or more kinds of films may be laminated in order to adjust the film stress.

The total thickness of the laminated etching stop film is generally 2000-2 μm, preferably 3000-15000 mm, and most preferably 4000-13000 mm. The total stress of the laminated etching stop film is generally 2 × 10 exp-9 dyne / cm ² or less, more preferably 1.8 × 10 exp-9 dyne / cm ² or less, and most preferably 1.5 × 10 exp-9 dyne / cm ^2. / cm ² or less.

  (5) A SiN film 311 is deposited on the heater by plasma CVD for the purpose of improving durability to form a protective film.

  (6) On this, Ta is deposited as a cavitation resistant film 312 by sputtering or the like and patterned. The thickness of this film is preferably 1000 to 5000 mm, more preferably 2000 to 4000 mm, and most preferably 2500 to 3500 mm.

  (7) A resin film 313 having high corrosion resistance is formed in order to increase the adhesion of the resin nozzle and to protect the back surface from the alkaline etchant. Then, the heater part and the ink supply port part are patterned.

  (8) In order to secure the ink flow path, the pattern 314 is formed of a resin that can be dissolved in a strong alkali or an organic solvent. This pattern is formed by a printing method or patterning with a photosensitive resin.

  (9) A coating resin layer 315 for forming nozzles is formed on the ink flow path pattern. Since this coating resin layer forms a fine pattern, a photosensitive resist is desirable, and further, the coating resin layer must have a property of not being deformed and altered by an alkali, a solvent, or the like when the resin layer having the flow path is removed.

  (10) Next, the coating resin layer of the flow path is patterned to form the ink discharge port 316 corresponding to the heater portion 309 and the external connection portion of the electrode. Thereafter, the coating resin layer is cured by light or heat.

  (11) A protective film 317 is formed with a resist to protect the nozzle forming surface side of the substrate.

(12) Using a photolithographic technique, remove the back surface of the ink supply port pattern portion 318 to expose the wafer surface using SiN or SiO ₂ on the back surface. The manufacturing method of the etching mask film on the back surface is not limited to plasma CVD, but may be LPCVD, atmospheric pressure CVD, thermal oxidation, or the like.

  (13) Next, an etching leading hole 319 is formed in a portion near the narrow angle of the parallelogram on the back surface (see the plan view 6 on the back surface). Generally, laser machining or the like is used, but electric discharge machining, blasting, or the like may be used.

  This lead hole can be as close as possible to the etching stop layer. The depth of the leading hole is generally 60% or more of the substrate thickness, preferably 70% or more, and optimally 80% or more. Also, it must not penetrate the substrate. By this leading hole, the oblique (111) plane generated from the narrow angle of the parallelogram is suppressed.

  (15) When this substrate is immersed in an alkaline etchant (KOH, TMAH, hydrazine, etc.) and anisotropic etching is performed so that the (111) plane appears, a through hole is formed.

  (16) A film such as SiN of the etching stop layer is partially removed by a chemical solution such as hydrofluoric acid or dry etching to open an ink supply port. Finally, the ink flow path forming material is removed to secure the ink flow path 320.

  In the above process, the substrate processing procedure is not particularly limited, and can be arbitrarily selected.

  Examples of the substrate of the ink jet recording head according to the present invention will be described below.

  FIG. 1 is a schematic view of a heater board substrate in the process of manufacturing an ink jet recording head showing an embodiment according to the present invention. A 5-inch ΦSi (110) wafer 201 was used as the substrate.

  On the patterned oxide film 202, the lower layer is AuCu (Al: Cu = 99.5: 0.5) 1000 Å, the TaSiN film (Ta: Si: N = 43: 42: 15) is 400 Å, and the upper layer is AlCu. A film (Al: Cu = 99.5: 0.5) was deposited by stacking 1000 Å and patterned to form a sacrificial layer 206 and wiring layers 203 to 205. The planar shape of the sacrificial layer was a parallelogram with a narrow angle of 70.5 degrees as shown in FIG. The sacrificial layer had a width of 150 μm and a length of 10 mm.

  An SiN film of 8000 mm was deposited thereon to form an etching stop layer 207.

  On the back surface of the substrate, an etching pattern 211 was formed by patterning an alkali resistant film (manufactured by HIMAL Hitachi Chemical Co., Ltd.) 210 on the oxide film 5000 Å so as to be a mirror image of the sacrificial layer.

  From here, through holes are opened toward the sacrificial layer on the surface by anisotropic etching to form ink supply ports.

  When the open short check of the wiring of this ink jet recording head was performed using a tester, the defect rate was 0.01%.

(Comparative example)
The other parts are the same as in Example 1. As shown in FIG. 10, a lower TaSiN film (Ta: Si: N = 43: 42: 15) is 400 mm, and an upper layer is an AlCu film (Al: Cu = 99.5: 0). .5) was deposited by stacking 2000 mm and patterned to prepare a substrate on which wiring and a heater were formed. When this substrate was subjected to open short check of wiring using a tester, the defect rate was 0.05%.

  From this, it was found that the three-layer wiring using two layers of AlCu has higher reliability than the two-layer wiring.

  A method for manufacturing the ink jet recording head of the present invention will be described step by step with reference to FIG.

As shown in FIG. 7A, a (110) -plane Si wafer 301 having a thickness of 630 μm and a 5-inch diameter was thermally oxidized to form a 12,000-thick SiO ₂ layer 302. Next, the supply port opening 303 was formed by patterning SiO ₂ . 1200 μm of AlCu film (Al: Cu = 99.5: 0.5) was deposited with a sputter. The sacrificial layer 305 and the electrode wiring 304 were formed by patterning as shown in FIG. The wiring material at the position where the heater portion is formed was removed by etching in advance as in 306. The width of the sacrificial layer was 140 μm, and the long side direction was 15 mm.

  Next, 400 Å of TaSiN 307 was deposited on the intermediate layer and 1000 Ａｌ of AlCu 308 was continuously deposited on the upper layer, and the upper layer wiring material was partially etched away in accordance with the ink supply port to expose the lower layer of TaSiN to form the heater portion 309. (Refer to the plan view 2) The size of the heater portion was 24 × 24 μm. The wiring was folded on a plane as shown in FIG. 2, and the individual signal supply line and the downstream ground power supply unit were formed by the same wiring.

As an etching stop layer, 8000 SiN films 310 were deposited by plasma CVD as shown in FIG. The deposition conditions of the SiN film at this time were SiH ₄ / NH ₃ / N ₂ = 500/1500/6300 sccm, pressure 150 mtorr, substrate temperature 380 ° C., and RF 1700 W.

For the purpose of improving durability, a SiN film 311 was deposited on the heater by plasma CVD to form a protective film. The deposition conditions for the SiN film at this time were SiH ₄ / NH ₃ = 500/2000 sccm, pressure 150 mtorr, substrate temperature 360 ° C., and RF 1700 W.

  On top of this, 2300 m of Ta was deposited by sputtering as an anti-cavitation film 312 and patterned.

  An alkali-resistant film (manufactured by HIMAL Hitachi Chemical Co., Ltd.) 313 is formed to increase the adhesion of the resin nozzle and to protect the back surface from the alkaline etchant. And heater part patterning is carried out.

  Polymethylisopropenyl ketone (Tokyo Ohka ODUR-1010) as a photosensitive resin was applied by 20 μm and patterned to form an ink flow path mold 314 as shown in FIG. 7 (8). Further, a photosensitive resin layer 315 shown in Table 1 was applied to a thickness of 12 μm and patterned to form ink discharge ports 316 as shown in FIG.

In order to protect the nozzle forming surface side, a protective film 317 was formed with a rubber resist (OBC manufactured by Tokyo Ohka Kogyo Co., Ltd.). The backside ink supply port 318 was formed by patterning the HIMAL film and SiO ₂ on the backside of the nozzle. This pattern was a parallelogram having a mirror image relationship with the surface sacrificial layer.

  Next, a non-penetrating etching lead hole 319 with a second harmonic of the YAG laser was opened as shown in FIG. 7 (12) in a portion adjacent to the narrow angle of the parallelogram window of the ink supply port pattern portion on the back surface. . At this time, the diameter of the hole was 25 to 30 μm, and the depth was 500 to 580 μm.

  This substrate was immersed in a 21% TMAH aqueous solution and anisotropically etched. The etchant temperature was 83 ° C. and the etching time was 7 hours and 20 minutes. This was an overetching time of 10% with respect to the time for just etching the thickness of the substrate of 630 μm.

  The etching proceeds to the AlCu sacrificial layer as shown in FIG. 7 (13), and stops before the etching stop layer. At this time, there was no crack in the etching stop layer, and no penetration of the etching solution into the flow path forming resin layer or the nozzle portion was observed.

Next, as shown in FIG. 7 (14), SiN in the etching stop layer was removed by the CDE method. Etching conditions were CF ₄ / O ₂ = 300/250 sccm, RF 800 W, and pressure 250 mtorr.

  As shown in FIG. 7 (15), the ink flow path 320 was formed by applying ultrasonic waves in methyl lactate to remove the flow path forming resin. Finally, after immersion in methyl isobutyl ketone, the protective film was removed by applying ultrasonic waves in xylene to complete an ink jet recording head.

  Using this ink jet recording head, a printing test was conducted at a discharge frequency of 14 KHz. A high-quality printed matter free from printing blur, density unevenness, and non-ejection of ink was obtained over the entire 15 mm width.

Schematic which shows the cross section of the board | substrate in the middle of the manufacturing process of the inkjet recording head by this invention. Schematic which shows the board | substrate plane in the middle of the manufacturing process of the inkjet recording head by this invention. The cross-sectional schematic of the board | substrate used for the experiment which leads to this invention. Schematic which shows the test progress of the board | substrate used for experiment to reach this invention. 1 is a schematic view showing an upper surface of a base substrate of an ink jet recording head according to the present invention. 1 is a schematic diagram showing the back surface of a base substrate of an ink jet recording head according to the present invention. The figure which shows the manufacturing-process flow of the inkjet recording head by this invention. The cross-sectional schematic of the board | substrate used for the experiment which leads to this invention. The cross-sectional schematic of the board | substrate used for the experiment which leads to this invention. The board | substrate cross section in the middle of the manufacturing process of the inkjet recording head of a comparative example. Schematic which shows the sacrificial layer remainder of the board | substrate used for the experiment leading to this invention. The figure which shows the result of the experiment leading to this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Si substrate 102 Sacrificial layer 103 Etching stop layer 104 Ink supply port opening 105 Etching lead hole 106 Alkali resist 201 Si substrate 202 Oxide film 203 Lower wiring layer 204 Heater layer 205 Upper wiring layer 206 Sacrificial layer 207 Etching stop layer 208 Heater 209 Oxidation film 210 Alkali resistant resin film 301 Silicon wafer substrate 302 Insulating film 303 Ink supply port pattern 304 Lower layer wiring 305 Sacrificial layer 306 Heater forming part 307 Heater material 308 Upper layer wiring 309 Heater 310 Etching stop layer 311 Heater protective film 312 Anti-cavitation film 313 Alkali-resistant resin film 314 Ink flow path forming material 315 Nozzle forming material 316 Discharge port 317 Protective film for anisotropic etching 318 Back surface supply port 319 Laser processing etching leading hole 320 Ink flow path

Claims (8)

  A step of forming an insulating film such as a silicon oxide film or a silicon nitride film on the silicon substrate as a livestock heat layer, a step of forming an ink discharge pressure generating element on the film, and a material susceptible to etching liquid on the surface of the silicon substrate. Depositing a thin film and forming a pattern (etching sacrificial layer) in the shape of the ink supply port, forming an etching stop layer of a silicon oxide film, a silicon nitride film or a mixture thereof on the pattern in the shape of the supply port, An opening is provided on the back surface on which the silicon oxide film or the silicon nitride film is formed, and the silicon in the portion serving as the ink supply port is removed by anisotropic etching, and the silicon oxide in the etching stop layer remaining in the ink supply port An ink jet comprising at least a step of removing the film, the silicon nitride film or a mixture thereof. A manufacturing method of an ink jet recording head, wherein the thin film pattern (etching sacrificial layer) in the shape of a supply port on the surface of the substrate is formed by laminating three layers of different materials Method.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the etching sacrificial layer has a lowermost layer as a wiring material, an intermediate layer as a heater material, and an upper layer as a wiring material.   The etching sacrificial layer is characterized in that the lowermost layer is Al or an alloy containing Al, the intermediate layer is an alloy layer containing at least two of Ta, Si, and N, and the upper layer is an alloy containing Al or Al. A method for manufacturing an ink jet recording head according to claim 1.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the lowermost layer of the etching sacrificial layer is an alloy containing Al and Cu.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the lowermost layer of the etching sacrificial layer is an alloy containing Al and Si.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the lowermost wiring layer of the etching sacrificial layer has a thickness of 400 mm or more.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein the heater layer as an intermediate layer of the etching sacrificial layer has a thickness of 1000 mm or less.   2. The method of manufacturing an ink jet recording head according to claim 1, wherein an etching solution used for the anisotropic etching is tetramethylammonium hydride (TMAH).

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