JP2008265196A - Ink-jet recording head and ink-jet recording head manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet recording head which is reduced in defective production caused by deflection by easing the deflection due to membrane stress of an Si substrate, and improved in yield at the time of anisotropic etching. <P>SOLUTION: (1) When a membrane layer is formed of a single layer, the membrane stress is eased by separating the membrane layer in any of sacrifice layers. (2) When the membrane layer is formed of multiple layers, the membrane stress is eased by separating the multi-layered film in the same sacrifice layer, and the yield of the anisotropic etching is improved by thickening the membrane thickness. Alternatively when the membrane stress is eased by separating the membrane layer in the different sacrifice layers, the membrane layer is present in the sacrifice layers, and therefore the yield at the time of the anisotropic etching is improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

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.

  Regarding the ink jet recording head, the ink jet recording head described in JP-A-54-51837 applies thermal energy to a liquid, and the liquid that has received the thermal energy is heated to generate bubbles. A droplet is ejected from the orifice at the tip of the recording head by the acting force, and the droplet adheres to the recording member to record information.

  A recording head applied to this recording method generally includes an orifice provided for discharging a liquid, and a heat acting portion that is a portion where heat energy for discharging a droplet communicated with the orifice acts on the liquid. A liquid discharge section having a liquid flow path as a part of the structure, a heat generation resistance layer as a heat conversion body that is a means for generating thermal energy, a heater protection layer that protects it from ink, and a resistance to protection from cavitation It has a cavitation layer and a heat storage layer (lower layer) for storing heat.

  Japanese Patent Laid-Open No. 9-11479 proposes a method in which a sacrificial layer is covered with an etching stop layer and an ink supply port is formed by anisotropic etching. Furthermore, Japanese Patent Laid-Open No. 10-181032 proposes a method for forming an ink supply port with high precision by anisotropic etching.

Briefly describing the process:
1) A silicon dioxide film is formed on the surface of a silicon substrate by thermal oxidation.
2) Next, a heating resistor is formed on the silicon dioxide film,
3) Remove the silicon dioxide film in place,
4) A poly-Si film was formed and formed on the portion from which silicon dioxide was removed to form a continuous sacrificial layer.
5) Furthermore, an etching stop layer made of a silicon nitride film is formed on the buried sacrificial layer continuous with the heating resistor,
6) Thereafter, the flow path forming layer and the nozzle forming layer are formed by a post process,
7) Perform anisotropic etching of silicon from the back surface with TMAH,
8) The silicon dioxide film is removed, and the sacrificial layer is removed with TMAH.
9) The ink jet recording head is formed by removing the etching stop layer at the ink supply port by RIE.
JP 54-51837 A Japanese Patent Laid-Open No. 9-11479 Japanese Patent Laid-Open No. 10-181032

  In a method for forming an ink jet recording head, an etching stop layer made of a silicon oxide film or a silicon nitride film is formed on a sacrificial layer.

  When a plurality of the sacrificial layers are formed, the area of the etching stop layer that covers the sacrificial layers also increases. Thereafter, there are processes such as flow path forming layer, nozzle forming layer formation, and anisotropic etching of silicon.

  However, when the etching stop layer (303) covering a plurality of sacrificial layers (302) is formed as an integral rectangle as shown in FIG. 3, the film of the etching stop layer is formed on the silicon substrate (301) by the film stress of the etching stop layer. When the stress is compressive, it is concave and when it is tensile, the convex warp occurs. Due to the warpage of the silicon substrate, in the process after the formation of the etching stop layer, there is a case where the conveyance failure due to the warp or the wafer cannot be attracted to the stage of the apparatus and becomes defective, resulting in a decrease in yield.

  Moreover, although the warpage of the silicon substrate can be prevented by reducing the film stress of the etching stop layer, the TMAH resistance tends to be weakened if the film stress is reduced, and the etching stop layer is etched when the sacrificial layer is etched by TMAH. Were also etched at the same time, cracking occurred and the yield was reduced.

  In this way, when a plurality of sacrificial layers are covered with an integral rectangle with a silicon oxide film or a silicon nitride film etching stop layer, a defect occurs in a later process due to warpage of the silicon substrate due to film stress. On the other hand, when the film stress is reduced, the TMAH resistance is weakened, and when the sacrificial layer is etched by anisotropic etching, there is a problem that the yield is reduced.

In order to solve the above problems, in the present invention, a heater protective film that protects a plurality of heat generating resistors that eject ink is formed, and further includes a heat generating resistor on which an anti-cavitation film is formed, and a sacrificial layer In a substrate for an ink jet recording head in which an ink supply port is formed by anisotropic etching using TMAH, with a silicon oxide film or a silicon nitride film being covered with an etching stop layer, a plurality of sacrificial layers are formed as shown in FIG. The sacrificial layer 102 is formed of a plurality of etching stop layers 103 made of a silicon oxide film or a silicon nitride film having a large film stress (−3 × 10 ⁹ dyne / cm ² or more and −7 × 10 ⁹ dyne / cm ² or less). The silicon substrate 101 was warped by separating the sacrificial layers and relaxing the film stress. Even if the etching stop layer is separated not only between the sacrificial layers but also separated between a plurality of sacrificial layers, for example, the warpage can be reduced.

  In addition, the etching stop layer may have a laminated structure. For example, the first layer may be a film having strong TMAH resistance, and the second layer may be a film having a small film stress. A similar effect can be achieved by a configuration in which the film stress is reduced by separating the same sacrificial layers.

  Further, since the film stress can be relieved by changing the place where the first layer and the second layer are separated as shown in FIG. Further, in this configuration, since the stacked etching stop layers are separated at different locations, there is always an etching stop layer also in the sacrificial layer. Therefore, the coverage of the etching stop layer is good, so that the anisotropic etching by TMAH is performed. The occurrence of defects was greatly reduced.

The total film stress of the laminated etching stop layer was -3 × 10 ⁹ dyne / cm ² or more and -7 × 10 ⁹ dyne / cm ² or less.

[Action]
A film having a compressive stress (−3 × 10 ⁹ dyne / cm ² or more) and having a TMAH-resistant silicon oxide film or silicon nitride film is separated between a plurality of sacrifice layers, The film stress was relieved to prevent warping of the silicon substrate. In addition, when the membrane (etching stop layer) has a laminated structure to suppress cracking due to anisotropic etching, the film stress is relieved by separating between the same sacrificial layers or different sacrificial layers, and the silicon substrate Prevented warping.

  By the above method, the film stress can be relaxed while maintaining the TMAH resistance of the etching stop layer, and the occurrence of defects during anisotropic etching is greatly reduced.

  As described above, according to the present invention, in the case of an etching stop layer composed of a single layer of a silicon nitride film, a silicon oxide film, and a SiON film having a film stress of compressive stress and excellent TMAH resistance, a plurality of layers are used. The silicon substrate was prevented from warping by separating the sacrificial layers formed to relieve the film stress.

  Further, in the case of an etching stop layer composed of a silicon nitride film, a silicon oxide film, or a SiON film, or two or more kinds of laminated films, they should be separated between the same sacrificial layers or different sacrificial layers. This relaxed the film stress and prevented the silicon substrate from warping.

  By the above method, in the case of a single layer structure, the film stress of the etching stop layer having a TMAH resistance with a film stress of compressive stress can be relaxed. Moreover, in the case of a laminated structure, each film stress was relaxed, and the occurrence of cracks in anisotropic etching was further suppressed by making the etching stop layer a laminated structure.

  That is, in the case of a laminated structure, a film having a large film stress but a TMAH resistance is formed in the first etching stop layer, and a film having a small stress is employed in the second etching stop layer. It has become possible to achieve the TMAH resistance and the required film thickness as an etching stop layer.

  As a result, defects due to warpage of the silicon substrate and cracking of anisotropic etching can be greatly reduced, thus improving the yield.

[Experiment] I Examination of film stress Film stress and warpage of silicon substrate Film stress and warpage of the silicon substrate were examined.

First, P-SiNx (silicon nitride film) having a thickness of 12000 mm was formed on a Si substrate by plasma CVD (P-CVD) using a SiH ₄ / NH ₃ / N ₂ gas.

  At this time, the film formation temperature was changed to change the film stress. Thereafter, the film stress and the warpage amount of the silicon substrate were measured with a film stress measuring device.

  The experimental results are shown in Table I below.

Table I Film stress and silicon substrate warpage Deposition temperature Film stress ( ⁹ dyne / cm ² ) Warpage
200 ℃ -2.9 × 10 50μ
250 ℃ -4.1 × 10 80μ
300 ° C -4.8 × 10 100μ
350 ° C -5.2 × 10 120μ
400 ℃ -5.9 × 10 130μ
As shown in Table I, as the film forming temperature is raised, the film stress increases in the compression direction, and the warpage amount of the silicon substrate also increases. When the stress was compression, it was warped in a concave shape.

The relationship between the film stress and the warpage of the silicon substrate was the same for the silicon oxide film.
[Experiment] II Examination of silicon substrate warpage Silicon substrate warpage amount and defect occurrence rate First, an Al-Cu metal film was formed on a Si substrate to a thickness of 2000 mm using a sputtering method, and each resist was used ( For example, OFPR (registered trademark) -800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was patterned into a predetermined etching sacrificial layer pattern by a photolithography process. Etching was performed by reactive ion etching (RIE) using a BCl ₃ / Cl ₂ gas system.

An etching stop layer made of P-SiNx was formed on this etching sacrificial layer using SiH ₄ / NH ₃ / N ₂ gas. At this time, the film stress was changed depending on the film formation temperature, and the warpage of the silicon substrate was changed. I changed the amount.

  Then, as a subsequent process, a heater made of TaSiN, a heater protective film made of P-SiNx, an alkali-resistant resist formed on the back surface of the Si substrate, the amount of warpage of the silicon substrate and poor conveyance due to each photolithographic process, and an apparatus stage The incidence of defects such as non-adsorption was examined.

  The experimental results are shown in Table II below.

Table II Silicon substrate warpage and defect rate (silicon substrate)
Deflection rate Defect occurrence rate
50μ 0%
80μ 0%
100μ 0%
120μ 1%
130μ 3%
As shown in Table II, when the warpage amount of the silicon substrate is 120 μm or more, in the subsequent steps, a defect occurs because it is not transported or attracted to the stage of the apparatus.

From this, it is understood that the warpage amount of the silicon substrate needs to be suppressed to 100 μm or less.
[Experiment] III Examination of film stress and cracks The film stress of the etching stop layer and the incidence of cracks during anisotropic etching were examined for the film thickness of the etching stop layer and cracks during anisotropic etching.
First, a metal film of AlCu is formed on a Si substrate to a thickness of 3000 mm using a sputtering method, and a predetermined etching sacrifice is performed by a photolithography process using a resist (for example, OFPR (registered trademark) -800 manufactured by Tokyo Ohka Kogyo Co., Ltd.). Patterned into a layer pattern.

Etching was performed by reactive ion etching (RIE) using a BCl ₃ / Cl ₂ gas system.

On this etching sacrificial layer, an etching stop layer made of P-SiNx was formed by plasma CVD (P-CVD) using SiH ₄ / NH ₃ / N ₂ gas, and the etching stop layer at this time The film stress was changed.

  Then, after forming an alkali-resistant resist on the back surface of the Si substrate by a photolithography process, anisotropic etching was performed, and then the state of etching stop layer cracking was observed.

  The experimental results are shown in Table III below.

Table III Etching stop layer film stress and crack generation rate Etching stop layer film stress Crack generation rate ( ⁹ dyne / cm ² ) (after anisotropic etching)
-1.9 × 10 2%
-2.9 × 10 0.5%
-4.1 × 100%
-4.8 × 10 0%
-5.2 × 10 0%
-5.9 × 100%
As shown in Table III, when the film stress of the etching stop layer is large in the compression direction, cracks are not generated by anisotropic etching. This is because the resistance of the etching solution (TMAH) increases when the film stress is large in the compression direction.

However, if the compressive stress exceeds −8.0 × 10 ⁹ dyne / cm ² , the stress is too strong and wrinkles are likely to occur in the film. Therefore, −7.0 × 10 ⁹ dyne / cm ² or less is desirable.

Therefore, the film stress of the etching stop layer is -3.0 × 10 ⁹ dyne / cm ²
Above -7.0 × 10 ⁹ dyne / cm ² is considered effective.
[Experiment] IV BHF (buffered hydrofluoric acid) selective etching experiment When the etching stop layer has a two-layer structure, the first layer is not etched when the second layer is etched to separate the different sacrificial layers. Selective etching is required.

  Therefore, selective etching was examined using P-SiNx (silicon nitride film) using plasma CVD using BHF.

  P-SiNx was deposited by plasma CVD under different gas species mixing ratios, and the etching rate by BHF was investigated.

First, 2 μm each of P-SiNx made of a gas system of SiH ₄ / NH ₃ / N ₂ was formed on a Si substrate by plasma CVD. The deposition conditions at this time were 200 sccm for SiH ₄ , 0 to 500 sccm for NH ₃ , 2000 sccm for N ₂ , a substrate temperature of 350 ° C., a pressure of 1600 mtorr, an RF power of 1000 W, and fixed except for the NH ₃ gas flow rate.

Next, each Si substrate was patterned into a predetermined pattern by a photolithography process using a resist (for example, OFPR (registered trademark) -800 manufactured by Tokyo Ohka Kogyo Co., Ltd.).
Then, it is immersed in BHF63U (Daikin Industries, HF: 6 mass%, NH ₄ F: 30 mass%, HF: NH ₄ F = 1: 6.25) for 3 minutes, and then the resist is peeled off and the etching amount is measured and etched. A rate comparison was made.

The experimental results are shown in Table IV below. Table IV NH ₃ addition amount and etching rate (BHF63U)
Etching experiment in SIH ₄ / NH ₃ / N ₂ system
NH ₃ addition amount Etching rate (wet)
NH ₃ 0sccm 60Å / min
NH ₃ 50sccm 100Å / min
NH ₃ 100sccm 230Å / min
NH ₃ 200sccm 1200Å / min
NH ₃ 300sccm 3700Å / min
NH ₃ 500sccm 5600Å / min
As shown in Table IV, it is possible to slow down the etching rate with BHF by not adding NH ₃ or reducing the flow rate to 100 sccm or less when forming P-SiNx, so only the upper layer film is etched by wet etching with BHF. Thus, it can be seen that selective etching in which P-SiNx of the lower layer film is hardly etched is possible.

As a result, P-SiNx not added with NH ₃ is formed as a first film by P-CVD and separated between a plurality of sacrificial layers, and a flow rate of NH ₃ is formed as a second film on the film. However, it is possible to form P-SiNx having a thickness of 200 sccm or more and to separate the first layer from a different sacrificial layer.
[Experiment] V Examination of etching stop layer structure and cracks Etching stop layer structure and incidence of cracking during anisotropic etching The etching stop layer structure and cracks when overetching during anisotropic etching were examined.

  First, a metal film of AlCu is formed on a Si substrate to a thickness of 3000 mm using a sputtering method, and a predetermined etching sacrifice is performed by a photolithography process using a resist (for example, OFPR (registered trademark) -800 manufactured by Tokyo Ohka Kogyo Co., Ltd.). Patterned into a layer pattern.

Etching was performed by reactive ion etching (RIE) using a BCl ₃ / Cl ₂ gas system.

On this etching sacrificial layer, an etching stop layer made of P-SiNx was formed by plasma CVD (P-CVD) using a SiH ₄ / NH ₃ / N ₂ gas to form a single layer structure.

Next, in order to form an etching stop layer, the first layer is formed on the sacrificial layer pattern of the Si substrate by plasma CVD (P-CVD) using SiH ₄ / NH ₃ / N ₂ -based gas. After forming an etching stop layer made of SiNx by 3000 mm, it was separated between the sacrificial layers by patterning. Similarly, an etching stop layer made of P-SiNx is formed using a SiH ₄ / NH ₃ / N ₂ gas, and is separated between the first and second sacrificial layers by patterning to form two layers as shown in FIG. The configuration.

  Then, after forming an alkali resistant resist on the back surface of the Si substrate by a photolithography process, overetching was performed when anisotropic etching with TMAH was performed, and the state of the etching stop layer cracking in the single layer configuration and the stacked configuration was observed. .

The experimental results are shown in Table V. Table V Etching stop layer configuration and crack generation rate Over etching time Crack generation rate (during anisotropic etching) Single layer configuration Two layer configuration
1Hr 0% 0%
2Hr 0% 0% 3Hr 0% 0%
4Hr 0% 0%
5Hr 0.1% 0%
6Hr 0.3% 0%
As shown in Table V, when the over-etching time during anisotropic etching becomes long, the single-layer structure is etched by TMAH and cracking occurs, but the two-layer structure does not cause cracking. This is because even if cracking occurs in the first layer, the layer is different, so cracking is unlikely to occur in the second layer, and the separation point of the etching stop layer is different. In this case, since at least one etching stop layer exists between the sacrificial layers, it is possible to prevent the etching solution from entering when the sacrificial layer is etched.

Thus, it can be seen that by forming the etching stop layer in two layers and separating between the different sacrificial layers, the etching stop layer also exists in the sacrificial layers, so that the generation of cracks can be further suppressed.
[Experiment] VI Study on Si substrate warpage Alleviation of Si substrate warpage was investigated by the etching stop layer separation method.

First, an Al metal film is formed on a Si substrate to a thickness of 2000 mm using a sputtering method, and a predetermined etching sacrifice is performed by a photolithography process using a resist (for example, OFPR (registered trademark) -800 manufactured by Tokyo Ohka Kogyo Co., Ltd.). Patterned into a layer pattern. Etching was performed by reactive ion etching (RIE) using a BCl ₃ / Cl ₂ gas system.

On this etching sacrificial layer, an etching stop layer made of P-SiNx was formed using SiH ₄ / NH ₃ / N ₂ -based gas. At this time, the film stress was set to −3.0 × at a film forming temperature of 350 ° C. 10 ⁹ dyne / cm ² or more.

Thereafter, this etching stop layer was patterned into the following three types of patterns by reactive ion etching (RIE) using SF ₆ / O ₂ -based gas.

(1) Pattern 1: Configuration that does not separate between sacrificial layers as shown in FIG.
(2) Pattern 2: Configuration separated between sacrificial layers as shown in FIG.
(3) Pattern 3: As shown in FIG.

Structure in which each layer is separated between different sacrificial layers After separating the sacrificial layers using SF ₆ / O ₂ gas of RIE with P-SiNx not added with NH ₃ as the first layer, NH ₃ is 200 sccm as the second layer. The P-SiNx added as described above was formed and separated with a layer of sacrificial layer different from the first layer with ammonium hydrogen fluoride to form a two-layer structure.

  At this time, the amount of warpage of each of three different Si substrates was measured.

  The experimental results are shown in Table VI below.

Table VI Pattern composition and silicon substrate warpage pattern composition Film stress ( ⁹ dyne / cm ² ) Warpage
(1) Structure No separation (Fig. 3) -5.1 × 10 140μ
(2) Configuration With separation (Fig. 1) -5.1 × 10 20μ
(3) Configuration With separation (Fig. 2) -5.1 × 10 25μ
(Two-layer structure)
As shown in Table VI, when the film stress of the etching stop layer is −3.0 × 10 ⁹ dyne / cm ² or more, if it is not separated between the sacrificial layers as shown in FIG. As described above, a conveyance failure and an apparatus stage suction failure are likely to occur.

It can be seen that even when the film stress is −3.0 × 10 ⁹ dyne / cm ² or more, the warpage of the Si substrate is relaxed to 100 μm or less by separation between the sacrificial layers as shown in FIG.

In addition, even if the etching stop layer has a two-layer structure of −3.0 × 10 ⁹ dyne / cm ² or more, the first and second layers can be separated between different sacrificial layers as shown in FIG. It can also be seen that the warpage is relaxed to 100 μm or less.

  Embodiments of the present invention will be specifically described based on examples.

  The method for producing the ink jet recording head according to the present invention will be specifically described below. FIG. 21 is a plan view when a plurality of sacrificial layers are formed. The first embodiment will be described with reference to FIG. 4 and subsequent drawings, with the A-A ′ sectional view as (a) and the B-B ′ sectional view (b).

(1) A heat storage layer 402 made of an insulating film SiO ₂ is formed on a silicon substrate 401 having a substrate surface orientation (100) of FIG. 4 by, for example, thermal oxidation or CVD, and an ink supply port is formed as shown in FIG. 4 by photolithography. A plurality of desired patterns (supply openings) 403 for providing a gap are formed (plan view FIG. 21).

(2) Al is deposited by sputtering as shown in FIG. 5 and then patterned to form a lower layer wiring 404 and a plurality of sacrificial layers 405. 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. At this time, the sacrificial layer pattern had a width of 160 μm and a length of 10 mm (plan view FIG. 21). For the sacrificial layer, a resist pattern was formed by a photolithography process, and then Al was etched with BCl ₃ / Cl ₂ gas by reactive ion etching (RIE).

(3) As an etching stop layer 406, 12,000 mm of P-SiNx films are deposited on this substrate surface by plasma CVD so as to cover a plurality of sacrificial layers as shown in FIG. The deposition conditions for the P—SiNx film at this time were SiH ₄ / NH ₃ / N ₂ = 160/100/2000 sccm, pressure 1500 mtorr, substrate temperature 350 ° C., and RF 1600 W. The total thickness of the laminated etching stop film is generally 3000 to 2 μm, preferably 6000 to 1.5 μm, and optimally 1 to 1.5 μm. The stress of the laminated etching stop film was a compressive stress of −4.7 × 10 ⁹ dyne / cm ² . The etching stop layer is separated between each sacrificial layer of the sacrificial layers formed by patterning by reactive ion etching (RIE) using SF ₆ / O ₂ gas as shown in FIG. 7A. This alleviated the warpage of the Si substrate.

  Note that it is not always necessary to separate the separation portions between the sacrificial layers, and the same effect can be obtained even if the separation portions are separated every few. It is preferable to separate at an optimum interval in consideration of the film stress.

  (4) A P-SiNx film is deposited by plasma CVD or the like to form an interlayer insulating film 407. Further, a contact hole 408 is formed in the interlayer insulating film so that the P-SiNx film of the etching stop layer is not etched (FIG. 8).

  At this time, since the etching stop layer is separated between the sacrificial layers and the film stress is relieved, the contact hole can be formed without the influence of the warp due to the film stress of the interlayer insulating film.

  (5) A heater unit 409 is formed as an ink discharge pressure generating element in accordance with the ink supply port. As the heater material, a metal film such as Ta, TaN, TaNSi or the like is deposited and patterned by sputtering, vacuum evaporation or the like. Further, a metal film of Al, Mo, Ni, Cu or the like is formed in the same manner as the upper electrode 410 for supplying power (FIG. 9).

  In addition, since the warpage is relaxed, the film stress of the metal film does not become a problem.

  (6) A P-SiNx film 411 is deposited on the heater by plasma CVD for the purpose of improving durability to form a protective film (FIG. 10).

  (7) On this, Ta is deposited as a cavitation resistant film 412 by sputtering or the like and patterned (FIG. 11, B-B ′ cross section). The thickness of this film is preferably 1000 to 5000 mm, more preferably 2000 to 4000 mm, and most preferably 2500 to 3500 mm.

  In this wiring and heater forming process, there is no problem due to warpage.

  Needless to say, there is no particular limitation on the order of forming the wiring and the heater.

  (8) A resin film 413 with 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 (FIG. 12).

  (9) In order to secure the ink flow path, the pattern 414 is formed of a resin that can be dissolved in a strong alkali or an organic solvent. This pattern is formed by printing or patterning with a photosensitive resin (FIG. 13).

  (10) A coating resin layer 415 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.

  (11) Next, the coating resin layer of the flow path is patterned to form the ink discharge port 416 corresponding to the heater part 409 and the external connection part of the electrode (FIG. 14). Thereafter, the coating resin layer is cured by light or heat.

  (12) A protective film 417 is formed with a resist to protect the nozzle forming surface side of the substrate (FIG. 15).

(13) Using a photolithographic technique, remove the pattern portion 418 of the ink supply port on the back surface to expose the wafer surface using SiN or SiO ₂ on the back surface (cross section BB ′ in FIG. 16). The shape of this pattern is 300 μm wide and 11 mm long (FIG. 22). 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.

  (14) When this substrate is immersed in an alkaline etchant (KOH, TMAH, hydrazine, etc.) and anisotropic etching is performed so that the (111) plane is exposed, a through hole having a rectangular planar shape is formed. The etched sacrificial layer is also etched (FIG. 17).

  At this time, the etching stop layer is separated between the sacrificial layers in order to relieve the film stress, and at the same time, it is resistant to compressive stress alkaline etchants (KOH, TMAH, hydrazine, etc.). Can be suppressed.

  (15) The P-SiNx film of the etching stop layer 406 separated between the plurality of sacrificial layers is partially removed by a chemical solution such as hydrofluoric acid or dry etching to open the ink supply port (FIG. 18). . Next, the etching protection film 417 is removed (FIG. 19), and finally the ink flow path forming material 414 is removed to secure an ink flow path 419 composed of a plurality of supply ports (FIG. 20).

In the above process, the substrate processing procedure is not particularly limited, and can be arbitrarily selected. The ink jet recording nozzle formed by the above-described process has a sacrificial layer formed of a plurality of etching stop layers (silicon nitride films) having a compressive stress of −3.0 × 10 ⁹ dyne / cm ² or more. If it is separated between the sacrificial layers, the warpage of the Si substrate is mitigated to prevent the transport failure due to the warpage of the Si substrate, the failure due to the device stage adsorption failure, and the film of compressive stress is alkali resistant, so etching Since the generation of cracks in the stop layer can be suppressed over the entire area, the yield has been improved.

  FIG. 21 is a plan view when a plurality of sacrificial layers in FIG. 21 are formed as in Example 1, with AA ′ cross-sectional view taken as (a), BB ′ cross-sectional view taken as (b), and P as an etching stop layer. A second embodiment using a -SiON film will be described with reference to FIGS.

(1) Al sacrificial layers were formed by the same process as in Example 1. A plurality of the sacrificial layers were formed by forming a resist pattern by a photolithography process and then etching Al with a BCl ₃ / Cl ₂ gas by reactive ion etching (RIE).

As an etching stop layer 506 on the substrate surface, a P-SiON film is deposited by 10000 by plasma CVD. The deposition conditions for the P—SiON film were SiH ₄ / N ₂ O / N ₂ = 200/1000/3500 sccm, pressure 1700 mtorr, substrate temperature 350 ° C., and RF 1000 W. The total thickness of the laminated etching stop film is generally 3000 to 2 μm, preferably 6000 to 1.5 μm, and optimally 1 to 1.5 μm. Further, the total stress of the laminated etching stop film is −3.3 × 10 ⁹ dyne / cm ² of compressive stress (FIG. 23).

(2) A plurality of etching stop layers 506 of this silicon oxide film (P-SiON film) are formed by patterning as shown in FIG. 24 using reactive ion etching (RIE) and CF ₄ / O ₂ gas. The sacrificial layers were separated to alleviate the warpage of the Si substrate, and it was confirmed that a film other than the silicon nitride film had the same effect as in Example 1 (FIG. 24).

  (3) Then, the structure shown in FIG. 25 is formed by the same process as in the first embodiment, and the ink supply port is formed by opening the through hole toward the sacrificial layer on the surface by anisotropic etching. In Example 2, no defect due to warpage of the Si substrate occurred.

The ink jet recording nozzle formed by the above process is separated by a plurality of sacrificial layers even if an etching stop layer P-SiON film having a film stress of −3.0 × 10 ⁹ dyne / cm ² or more is used. By mitigating substrate warpage and preventing defects due to Si substrate warpage and device stage adsorption failure, it is possible to prevent defects after this process, and since the film is dense with compressive stress, the etching stop layer Cracking no longer occurred across the entire area, leading to improved yield.

  As described above, it was confirmed that the film stress can be alleviated by separation between the sacrificial layers different from that in Example 1 except for the silicon nitride film.

  FIG. 21 is a plan view when a plurality of sacrificial layers in FIG. 21 are formed as in the first embodiment, where the AA ′ cross-sectional view is (a) and the BB ′ cross-sectional view is (b). In order to suppress cracking of the etching stop layer during etching, Example 3 in which the etching stop layer has a two-layer structure will be described.

(1) An Al—Cu sacrificial layer was formed by the same process as in Example 1. A plurality of the sacrificial layers were formed by forming a resist pattern by a photolithography process and then etching Al—Cu with BCl ₃ / Cl ₂ gas by reactive ion etching (RIE). As a first etching stop layer 606 on this substrate surface, 3000 μm is deposited by plasma CVD so as to cover a sacrificial layer on which a plurality of P-SiNx films are formed. The deposition conditions for the P—SiNx film at this time were SiH ₄ / NH ₃ / N ₂ = 160/50/2000 sccm, pressure 1500 mtorr, substrate temperature 350 ° C., and RF 1200 W. Subsequently, as the second etching stop layer 607, a film of SiH ₄ / NH ₃ / N ₂ = 160/100/2000 sccm, pressure 1300 mtorr, substrate temperature 350 ° C., and RF 1600 W is formed on the first etching stop layer 606. A 10,000-inch P-SiNx film having the conditions was formed.

The total thickness of the laminated etching stop film is generally 3000 to 2 μm, preferably 6000 to 1.5 μm, and optimally 1 to 1.5 μm. The total stress of the laminated etching stop film is a compressive stress of −5.1 × 10 ⁹ dyne / cm ² (FIG. 26).

(2) The stacked two-layer etching stop layers 606 and 607 are simultaneously patterned by reactive ion etching (RIE) using SF ₆ / O ₂ gas as shown in FIG. The warp of the Si substrate was alleviated by separating the sacrificial layers formed (FIG. 27).

  (3) Then, the structure shown in FIG. 28 is formed by the same process as in the first embodiment, and the ink supply port is formed by opening the through hole toward the sacrificial layer on the surface by anisotropic etching.

  In Example 3, no defect due to warpage of the Si substrate occurred.

The inkjet recording nozzle formed by the above process has a two-layer structure by simultaneously forming an etching stop layer (silicon nitride film) having a film stress of −3.0 × 10 ⁹ dyne / cm ² or more. Separation between the same sacrificial layers of the layers alleviated the warpage of the Si substrate, and the two-layer structure further suppressed the occurrence of cracks during anisotropic etching.

  In this way, the two-layered etching stop layer formed simultaneously is separated between the two sacrificial layers to relieve the film stress, thereby preventing the conveyance failure due to the warpage of the Si substrate and the failure due to the apparatus stage adsorption failure. . In addition, by forming two layers of compressive stress films, it was possible to prevent cracking of the etching stop layer over the entire area, leading to an improvement in yield. That is, as in this example, by forming a film having a large film stress but having a TMAH resistance in the first etching stop layer and adopting a film having a low stress in the second etching stop layer, It has become possible to achieve the TMAH resistance and the required film thickness as an etching stop layer.

  FIG. 21 is a plan view when a plurality of sacrificial layers in FIG. 21 are formed as in the first embodiment, where the AA ′ cross-sectional view is (a) and the BB ′ cross-sectional view is (b). In order to suppress cracking of the etching stop layer during etching, the second layer is formed after the first etching stop layer is separated from the sacrificial layer so that the film stress can be further reduced when the etching stop layer has a two-layer structure. Example 4 will be described in which the etching stop layer is separated between sacrificial layers different from the first layer.

(1) An Al—Cu sacrificial layer was formed by the same process as in Example 1. A plurality of sacrificial layers were formed by forming a resist pattern by a photolithography process and then etching Al—Cu by reactive ion etching (RIE) using a BCl ₃ / Cl ₂ gas. An etching stop layer 607 was formed by depositing 3000 P-SiNx films by plasma CVD so as to cover the plurality of sacrificial layers. The deposition conditions of the P-SiNx film at this time were SiH ₄ / N ₂ = 160/2000 sccm, pressure 1600 mtorr, substrate temperature 350 ° C., and RF 800 W (FIG. 29).

(2) This etching stop layer 706 is patterned by RIE using SF ₆ / O ₂ gas as shown in FIG. 30 and separated between a plurality of sacrificial layers to form a first etching stop layer film As the stress was relaxed, a first etching stop layer was formed (FIG. 30).

(3) A 10,000-thick P-SiNx film is deposited on the first etching stop layer 706 as a second etching stop layer. The deposition conditions for the P—SiNx film at this time were SiH ₄ / NH ₃ / N ₂ = 160/300/2000 sccm, pressure 1600 mtorr, substrate temperature 350 ° C., and RF 1200 W.

The total thickness of the laminated etching stop film is generally 3000 to 2 μm, preferably 6000 to 1.5 μm, and optimally 1 to 1.5 μm. The total stress of the laminated etching stop film is a compressive stress of −4.5 × 10 ⁹ dyne / cm ² (FIG. 31).

  (4) This substrate is patterned by a photolithographic process, immersed in a BHF63U solution for 4 min, and only the second P-SiNx film (10000 mm) is etched to separate it between a sacrificial layer different from the first etching stop layer. Then, when the film stress of the second etching stop layer was relaxed, an etching stop layer having two layers 706 and 707 was formed (FIG. 32).

  (5) Then, the structure shown in FIG. 33 is formed by the same process as in the first embodiment, and the ink supply port is formed by opening the through hole toward the sacrificial layer on the surface by anisotropic etching.

  In Example 4, no defect due to warpage of the Si substrate occurred.

In the inkjet recording nozzle formed by the above process, an etching stop layer (silicon nitride film) having a film stress of −3.0 × 10 ⁹ dyne / cm ² or more is separated from the first etching stop layer between the sacrifice layers. After the film stress is relaxed, the second etching stop layer is separated between the sacrificial layers different from the first layer by selective etching of the wet etching so that the film stress can be further relaxed. A two-layer structure that can further suppress the occurrence of cracks was adopted.

  Necessary as a TMAH resistance and etching stop layer by forming a film with high TMAH resistance in the first etching stop layer and a low stress film in the second etching stop layer It became possible to realize a suitable film thickness.

  Thus, since the film stress of the first layer and the second layer of the etching stop layer is individually reduced for the warp of the Si substrate, it is more effective against the warp, and the conveyance failure due to the warp of the Si substrate, It is possible to prevent defects due to poor device stage adsorption. Furthermore, with this configuration, there is always one etching stop layer on the sacrificial layer and between the sacrificial layers, so that the etching solution can be prevented from entering. Generation of cracks during anisotropic etching can be suppressed.

  This allowed us to further improve the yield.

1 schematically shows a cross section of a base substrate of an ink jet recording head according to the present invention. Schematic showing a cross section of the base substrate of the ink jet recording head according to the present invention in a two-layer configuration. Diagram showing problems with the prior art Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Schematic showing the manufacturing process flow of the ink jet recording head of Example 1 according to the present invention. Sacrificial layer plan view of Examples 1 to 4 Plan view of back side of Examples 1 to 4V Schematic showing a substrate cross section during the manufacturing process of the ink jet recording head of Example 2 according to the present invention Schematic showing a substrate cross section during the manufacturing process of the ink jet recording head of Example 2 according to the present invention Schematic showing a substrate cross section during the manufacturing process of the ink jet recording head of Example 2 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 3 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 3 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 3 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 4 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 4 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 4 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 4 according to the present invention Schematic showing the cross section of the substrate during the manufacturing process of the inkjet recording head of Example 4 according to the present invention

Explanation of symbols

101 Si substrate 102 Multiple sacrificial layers 103 Etching stop layer 201 Si substrate 202 Multiple sacrificial layers 203 First etch stop layer separated between sacrificial layers 204 Separated between sacrificial layers different from the first layer 2 Etching stop layer 301 Si substrate 302 Multiple sacrificial layers 303 Etching stop layer 401 Si substrate (100)
402 Heat storage layer 403 Multiple supply port openings 404 Lower layer wiring electrode 405 Multiple formed sacrificial layers 406 Etching stop layers (silicon nitride films) separated between the sacrificial layers
407 Interlayer insulating film 408 Contact hole 409 Heater 410 Upper layer wiring 411 Protective film 412 Anti-cavitation film 413 Adhesion improving resin film 414 Ink flow path forming material 415 Nozzle forming material 416 Ejection port 417 Etching protective film 418 Back surface supply port 419 Ink Channel 501 Si substrate (100)
502 SiO ₂
503 Multiple supply port openings 504 Lower wiring electrode 505 Multiple formed sacrificial layers 506 Etching stop layer (silicon oxide film) separated between sacrificial layers
507 Interlayer insulating film 508 Heater 509 Upper layer wiring 510 Protective film 511 Anti-cavitation film 512 Resin film for improving adhesion 513 Ink flow path forming material 514 Nozzle forming material 515 Protective film for etching 601 Si substrate (100)
602 Heat storage layer 603 Multiple supply port openings 604 Lower layer wiring electrode 605 Multiple sacrificial layers (AlCu2000)
606 First etching stop layer (P-SiNx, 3000cm) separated between the same sacrificial layers
607 Second etching stop layer (P-SiNx, 10000 mm) separated between the same sacrificial layers
608 Interlayer insulating film 609 Heater 610 Upper wiring 611 Protective film 612 Anti-cavitation film 613 Resin film for improving adhesion 614 Ink flow path forming material 615 Nozzle forming material 616 Protective film for etching 701 Si substrate (100)
702 Heat storage layer 703 Multiple supply port openings 704 Lower wiring electrode 705 Multiple sacrificial layers (AlCu2000)
706 First etch stop layer (P-SiNx, 3000 mm) separated between different sacrificial layers
707 Second etching stop layer (P-SiNx, 10000 mm) separated by sacrificial layer different from the first layer by wet etching
708 Interlayer insulating film 709 Heater 710 Upper layer wiring 711 Protective film 712 Anti-cavitation film 713 Resin film for improving adhesion 714 Ink flow path forming material 715 Nozzle forming material 716 Protective film for etching

Claims (4)

  A heater protective film for protecting a plurality of heat generating resistors for discharging ink is formed. The heater protective film is provided with a cavitation-resistant film formed on the heater protective film, and the size of the ink supply port is defined by etching. In an inkjet recording head substrate in which a plurality of sacrificial layers are formed, an etching stop layer is formed on the sacrificial layer, and an ink supply port is formed by etching, the etching stop layer is a single layer or a laminated film An ink jet recording head characterized in that the ink jet recording head is separated at at least one place between the sacrificial layers.   2. The ink jet recording head according to claim 1, wherein the etching stop layer has a multilayer structure and is separated between different sacrificial layers.   3. The ink jet recording head according to claim 1, wherein the etching stop layer is a silicon nitride film, a silicon oxide film, a single layer of SiON, a laminate of each, or two or more kinds of laminate films. 4. The ink jet recording head according to claim 1, wherein a film stress of the separated etching stop layer is a film stress of −3 × 10 ⁹ dyne / cm ² or more of compressive stress.

Images