JP2000177135A - Substrate for ink-jet recording head, ink-jet recording head and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the life and the reliability while achieving a thinner film by providing a heat generating resistor comprising a first heat generating resistor provided on the lower layer of an electrode wiring pattern connected with the heat generating resistor, and a second heat generating resistor provided between a protection film and the electrode wiring pattern. SOLUTION: After providing a heat accumulating layer 12 on an Si substrate 11 by forming an SiO2 film by a thermal oxidation method, a CVD method or the like, a heat generating resistor (TaN layer) 13 as the first layer, and an Al layer 14 as an electrode wiring are formed on the heat accumulating layer 12 by reactive sputtering. A wiring pattern is formed by a photolithography method, and etching is executed for forming a pattern on the cross-sectional structure. The part 20 with the Al partially taken out is provided as a heat generating part. Then, a second heat generating resistor (TaN layer) 15 is formed again. The patterning operation is executed in the same shape as in the first layer heat generating resistor by the photolithography method. An SiN is formed as a protection film 16, and a Ta film 17 is formed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate for an ink jet recording head, an ink jet recording head, and a method for manufacturing the same.

[0002]

2. Description of the Related Art The ink jet recording system disclosed in U.S. Pat. No. 4,723,129 or U.S. Pat. No. 4,740,796 is a high-speed, high-density, high-precision, high-quality recording. In recent years, it has attracted particular attention because it is suitable for colorization and compactness.
In the above-described ink jet recording system, in a recording head that foams ink by using thermal energy and discharges it to a recording medium, a heating resistor for foaming ink and wiring for making electrical connection are formed on the same substrate. In general, a substrate for an ink jet recording head is inserted into the substrate, and a nozzle for discharging ink is formed thereon. The inkjet recording head substrate is variously devised from the viewpoint of structurally small size and simplicity, and on the other hand, from the viewpoint of saving the input electric energy. In particular, many ideas are found in the shape and arrangement of the heating resistor connected to the wiring constituting the heating section. The most common configuration is a two-layer structure in which the lower layer has a heating resistor material and the upper layer has an Al electrode material layer, and only the heating section removes the upper layer of Al. As a result, the resistance of the heat-generating portion increases, and a current flows, thereby generating thermal energy for foaming the ink. Also,
A protective film for protecting the heat generating resistor and the wiring is provided on the heat generating portion. Then, the configuration of this protective film determines the performance of the inkjet head, for example, power consumption,
And it is an important factor that determines the service life.

However, in the structure of the conventional protective film,
Reducing power consumption and increasing film reliability and service life are conflicting requirements. For example, the power consumption for foaming the ink is less because the thickness of the film between the heating resistor and the surface in contact with the ink is thinner, the thermal conductivity is larger, and the escape of heat to a portion other than the ink side is reduced. Help me. That is, the thinner the protective film, the higher the energy efficiency.

On the other hand, if the protective film is thin, a pinhole is formed in the protective film, the step portion of the wiring cannot be sufficiently covered, and the step portion is insufficiently covered.
As a result, ink penetrates from there, causing corrosion of wiring and corrosion of the heating resistor, resulting in a decrease in reliability,
The life is shortened.

Here, it is known that the film quality of the protective film can be improved by increasing the temperature at the time of film formation. Since the growth of hillocks and the like due to the Al wiring is remarkably observed, the Al wiring is corroded by the hillock even if the film quality of the step portion is improved. Therefore, in order to prevent the wiring from being corroded by the hillocks, it is necessary to at least sufficiently secure the protective film on the wiring.

Further, if the order of the Al wiring and the heating resistor can be reversed, the problem caused by the hillock of the Al wiring can be avoided. , The film quality of the heating resistor in the stepped portion deteriorates, and the resistance value greatly varies, causing a practical problem.

To solve such a problem, Japanese Patent Application Laid-Open No. HEI 9-197572 discloses a configuration in which only the portion related to foaming of the protective film is made thinner, thereby reducing power consumption and increasing the reliability of the film and extending the life. It is disclosed in JP-A-8-112902.

That is, a plurality of heating resistors for applying heat to the ink, a plurality of wires electrically connected to the heating resistors, and a plurality of heating portions formed by the heating resistors exposed from the wires. Preparing a substrate having: a step of coating a first insulating protective film on the heating resistor and the wiring of the substrate; and wet-etching a portion of the first insulating protective film on the heating section. And a step of coating a second insulating protective film on the etched first insulating protective film, wherein an etched portion of the first insulating protective film in a longitudinal direction of the heat generating portion is formed. Discloses a configuration in which the first and second insulating protective films for covering the wiring are provided at least 1/2 or more of the sum of the thicknesses of the end portions of the heat generating portion.

[0009]

Here, the heat-generating resistor generates heat over the entire surface, but the peripheral portion of the resistor has a large escape of heat, so that the temperature of the peripheral portion decreases and does not contribute to foaming. Almost 4 inward from the periphery of the heating resistor
It has been obtained from the foaming observation that only the inner region of about μm (this region is referred to as the effective foaming region) is obtained from the foaming observation. However, in the configuration described in the above publication, the thick portion of the protective film is formed by the heating resistor. This also affects the original effective foaming area, which may result in a smaller actual effective foaming area. This reduction in the effective foaming area is not so problematic when the arrangement pitch of the nozzles is not so high, but as the nozzles are arranged at a high density, the area of the heating resistor becomes smaller with almost no change in the electrode thickness. It becomes something that cannot be ignored.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a substrate for an ink jet recording head capable of improving the life and reliability of a thin film. Another object of the present invention is to provide a substrate for an ink jet recording head which has both a measure against an effective temperature drop around the heating resistor and an improvement in the life and reliability for the above-mentioned thinning. I have.

[0011]

Means for Solving the Problems The present invention is characterized by the following constitution in order to achieve the above object. That is, the inkjet recording head substrate of the present invention is formed with a plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors on the substrate,
In a substrate for an ink jet recording head, a protective film for protecting the heating resistor and the electrode wiring pattern for protecting them from ink is formed, wherein the heating resistor is
A first heating resistor provided below the electrode wiring pattern connected to the heating resistor, and a second heating resistor provided between the protective film and the electrode wiring pattern. It is characterized by.

Further, in the ink jet recording head of the present invention, a plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors are formed on a substrate, and the heating resistor and the electrode wiring patterns are formed. In the inkjet recording head having an ink jet recording head substrate on which a protective film for protecting them from ink is formed, an ejection port for ejecting ink, and a liquid path communicating with the ejection port, A first heating resistor provided below the electrode wiring pattern connected to the heating resistor, and a second heating resistor provided between the protective film and the electrode wiring pattern. And a resistor.

Further, according to the method of manufacturing an ink jet recording head of the present invention, a plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors are formed on a substrate. Ink jet recording having a substrate for an ink jet recording head in which a protective film for protecting them from ink is formed on an electrode wiring pattern, an ejection port for ejecting ink, and a liquid path communicating with the ejection port In a method of manufacturing a head, a first
Forming the heat generating resistor, and forming the electrode wiring pattern on the first heat generating resistor and connected to the first heat generating resistor except for a heat generating portion of the heat generating resistor; A step of covering the electrode wiring pattern with a second heating resistor; and a step of forming the protective film on the second heating resistor.

[0014]

According to the above-described structure, by forming a heating resistor vertically above and below an electrode connected to the heating resistor, it is possible to reduce the thickness of the protective film on the heating resistor. Power saving can be achieved.
Further, since it is not necessary to reduce the effective foaming area, it is possible to provide a highly reliable ink jet recording head corresponding to high density.

According to the above configuration, the heating resistor is disposed on the upper and lower surfaces of the electrode connected to the heating resistor as described above, so that the film on the upper surface is an Al layer for forming an electrode wiring pattern when forming the protective film. Hillocks can be suppressed, whereby the thickness of the protective film can be reduced, and the electrode wiring can be connected to the heating resistor on the lower surface in a plane, and a stable resistance value can be secured. Also, when the thickness of the protective film on the heat generating portion exceeds 700 nm,
The effect of lowering the power consumption is not much seen. Therefore, the thickness of the protective film is preferably set in the range of 200 to 700 nm. Regarding the formation of the protective film, sputtering, CVD, plasma CVD, LP (low-
pressure), and particularly when the protective film is formed by an LPCVD method having a film forming temperature of 700 to 800 ° C. which is higher than other manufacturing methods, the film quality is extremely excellent. This is preferable because it becomes possible.

Further, according to the above configuration, of the upper and lower heating resistors, the heating resistor disposed on the lower surface of the electrode wiring pattern is separated at a heating portion of the heating resistor, and the heating resistor is separated from the heating resistor. By arranging the heating resistor only in the peripheral portion, the resistance of the heating resistor can be further increased.

Further, according to the above configuration, the heating resistor disposed on the lower surface of the electrode wiring pattern has a portion corresponding to the heating center of the heating portion of the heating resistor removed, and only the heating peripheral portion is disposed. By adopting the configuration described above, a large amount of current can flow in the peripheral portion of the heating resistor where the effective temperature becomes low, thereby increasing the temperature in the peripheral portion and further expanding the foaming region. An arrangement with a high-density pitch can be advantageously realized.

[0018]

Embodiments of the present invention will be described below. [Embodiment 1] FIG. 1 is a best representative drawings features of the present invention, x ₁ is a plan view of a heating resistor, it indicated by Figure 2
It is a sectional view taken along the one-dot chain line in -x _2. In the figure, 11 is a Si substrate, and 12 is Si as a heat storage layer.
O ₂ film, the first layer of the heating resistor layer 13, Al layer as a wiring pattern 14, 15 is a heating resistor layer of the second layer, SiN film as a protective film 16, 17 cavitation destruction Ta as a cavitation-resistant film that protects the protective film from being damaged.

Hereinafter, description will be made step by step. The substrate of the heat generating portion according to the present embodiment uses the Si substrate 11. This S
An SiO ₂ film is formed on the i-substrate by a thermal oxidation method, a CVD method, a sputtering method, or the like. This becomes the heat storage layer 12 below the heating resistor. Hereinafter, the procedure of the process will be described with reference to FIG. The TaN layer 13 is formed on the heat storage layer 12 by reactive sputtering as the first heating resistor.
Is formed to a thickness of about 50 nm and an Al layer 14 as an electrode wiring to a thickness of 500 nm as shown in FIG. Next, a wiring pattern is formed by using a photolithography method, and etching is performed by an Al wet etching method and a TaN reactive ion etching method.
A pattern is formed on the cross-sectional structure of FIG. Here, a portion where Al is partially removed, 20 in FIGS. 1, 2, and 3-(c) is a heat generating portion. Next, the heating resistor TaN is again formed as a second layer film with a thickness of 50 nm by reactive sputtering, and then patterned by photolithography into the same shape as the first layer heating resistor. . This gives A
The l layer is completely sandwiched between the upper and lower surfaces, and growth of hillocks and the like due to heat is eliminated. Next, 500 nm of SiN is formed as a protective film by a CVD method at a film forming temperature of 450 ° C.
Further, Ta is formed to a thickness of 200 nm by sputtering, and finally a Ta film and a protective film SiN are formed by photolithography.
Was patterned to expose an Al pad for connection to an external power supply. The performance was confirmed by assembling the inkjet head substrate manufactured as described above into an inkjet head. Usually, the power is reduced by 20% and the life is 1 × 10 ⁸ pulses / nozzle or more per 1 μm of the protective film. There was no difference as compared with that of 1 μm.

[Embodiment 2] In the first embodiment, a configuration is adopted in which the heating resistor layers are provided above and below the electrode, but with such a configuration alone, the heating resistors are superposed in two layers. Therefore, the resistance value decreases. Therefore, in the second embodiment, as a method of increasing the resistance of the heating resistor, the lower heating resistor is cut off. That is, FIG.
As shown at 21 in FIG. 5, the pattern of the lower layer is only in the vicinity of the Al electrode. Actually, the width of the heating resistor protruding from the Al electrode was set to 4 μm. As a result, the upper and lower heating resistors were sufficiently in contact with each other, so that the resistance value did not vary and the heating resistor could be increased in resistance.

[Embodiment 3] In the second embodiment, the lower heating resistor is provided only in the vicinity of the Al electrode. However, as the third embodiment, the lower heating resistor is removed only at the center as shown in FIG. Only the peripheral part is left. Specifically, the lower heating resistor at a portion 4 μm inside the upper heating resistor pattern was removed by a photolithography process and TaN dry etching. As a result, in the vicinity of the electrode, the upper and lower heating resistors were sufficiently in contact with each other, and the resistance value did not vary. Further, since more heat is generated in the peripheral portion of the heating resistor, the temperature of the peripheral portion rises, and the size of the bubble can be further increased.

(Other Embodiments) An ink jet recording head and an ink jet recording apparatus to which the substrate for an ink jet recording head of the present invention can be applied will be described below. FIG. 8 is a schematic configuration diagram of such an ink jet recording head. An electrothermal converter 1103, a wiring 1104, and a liquid path wall 11 are formed on a substrate 1102 through semiconductor processing steps such as etching and vapor deposition sputtering.
05, an inkjet head composed of a top plate 1106 is shown. The recording liquid 1112 is supplied from a liquid storage chamber (not shown) into a common liquid chamber 1108 of the head 1101 through a liquid supply pipe 1107. 1 in the figure
Reference numeral 109 denotes a liquid supply pipe connector. Common liquid chamber 110
The liquid 1112 supplied to the inside 8 is supplied into the liquid passage 1110 by a so-called capillary phenomenon, and is stably held by forming a meniscus at the discharge port surface (orifice surface) at the front end of the liquid passage. Here, by supplying electricity to the electrothermal converter 1103, the liquid on the electrothermal converter surface is heated rapidly,
Bubbles are generated in the liquid path, and the liquid is discharged from the discharge port 1111 communicating with the liquid path due to expansion and contraction of the bubbles to form droplets. FIG. 9 is an external view of an ink jet recording apparatus to which the present invention is applied. In FIG. 9, a spiral groove 5005 of a lead screw 5004 that rotates via driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotations of a driving motor 5013 is illustrated. The engaging carriage HC has a pin (not shown),
It is reciprocated in the direction of the arrow. Reference numeral 5002 denotes a paper holding plate which applies paper to the platen 500 in the carriage movement direction.
Press against 0. Reference numerals 5007 and 5008 denote home position detecting means for confirming the presence of a carriage lever 5006 in this region by photocouplers and switching the rotation direction of a motor 5013. Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the print head. Reference numeral 5015 denotes suction means that suctions the inside of the cap, and performs suction recovery of the print head through the opening 5023 in the cap. Reference numeral 5017 denotes a cleaning blade.
Reference numeral 9 denotes a member that enables the blade to move in the front-rear direction, and these members are supported by the main body support plate 5018. It goes without saying that the blade is not limited to this form and a known cleaning blade can be applied to this example. Also, 50
Reference numeral 12 denotes a lever for starting suction for suction recovery, which moves with the movement of the cam 5020 engaging with the carriage, and the driving force from the drive motor is controlled by a known transmission means such as clutch switching or the like. . The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5004 when the carriage comes to the home position side area. Any operation can be applied to this example as long as the operation is performed. Each of the configurations described above is an excellent invention when viewed alone or in combination, and shows preferred configuration examples for the present invention. The present device has a drive signal supply unit for driving the ink ejection pressure generating element.

[0023]

As described above, according to the present invention,
By arranging the heating resistor vertically above and below the electrode connected to the heating resistor, the protective film on the heating resistor can be made thinner, and power can be saved. Further, according to the present invention, the heat generating resistor disposed on the lower surface of the electrode wiring pattern is separated at a heat generating portion of the heat generating resistor, and is arranged only at a peripheral portion of the electrode wiring pattern portion. Accordingly, it is possible to increase the resistance of the heating resistor while maintaining the performance of the configuration in which the heating resistor is arranged vertically above and below the electrode connected to the heating resistor. Further, according to the present invention, the heating resistor disposed on the lower surface of the electrode wiring pattern is such that a portion corresponding to a heating center portion in a heating portion of the heating resistor is removed, and only the heating peripheral portion is disposed. With this configuration, the foam size can be increased relative to the width of the heating resistor, and an arrangement with a high-density pitch can be advantageously realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a substrate according to a first embodiment of the present invention, taken as x ₁ −
It is a cross-sectional view taken along one-dot chain line of x _2.

FIG. 2 is a plan view of the substrate according to the first embodiment of the present invention.

FIG. 3 is a flowchart of a manufacturing process of the substrate according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a substrate plan view 5 according to a second embodiment of the present invention as x ′ _1.
-X' is a cross-sectional view taken along one-dot chain line in _2.

FIG. 5 is a plan view of a substrate according to a second embodiment of the present invention.

FIG. 6 is a plan view of a substrate according to a third embodiment of the present invention, taken as x ″ _1.
It is sectional drawing cut | disconnected by the dashed-dotted line of -x " ₂ .

FIG. 7 is a plan view of a substrate according to a third embodiment of the present invention.

FIG. 8 is a schematic illustration of an inkjet head to which the inkjet head substrate of the present invention can be applied.

FIG. 9 is a schematic perspective view showing an inkjet apparatus using an inkjet head to which the substrate for an inkjet head of the present invention can be applied.

[Explanation of symbols]

 11: Si substrate 12: SiO2 heat storage layer 13: lower layer heating resistor 14: Al electrode 15: upper layer heating resistor 16: protective film SiN 17: anti-cavitation film Ta 20: heating section 21: lower layer heating resistor end 22: Lower heating resistor end

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyuki Imanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Masahiko Ogawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation

Claims (17)

[Claims] A plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors are formed on a substrate;
An ink jet recording head substrate, wherein a protective film for protecting them from ink is formed on the heating resistor and the electrode wiring pattern, wherein the heating resistor is connected to the heating resistor. A substrate for an ink jet recording head, comprising: a first heating resistor provided below a pattern; and a second heating resistor provided between the protective film and the electrode wiring pattern. 2. The substrate according to claim 1, wherein said electrode wiring is made of Al. 3. The substrate for an ink jet recording head according to claim 1, wherein said protective film has a thickness of 200 to 700 nm. 4. The ink jet recording apparatus according to claim 1, wherein the first heating resistor is separated at a heating portion of the heating resistor and is disposed only at a peripheral portion of the electrode wiring pattern. Substrate for head. 5. A heat generating portion of said first heat generating resistor, a portion corresponding to a heat generating central portion of a heat generating portion is removed,
2. The substrate for an ink jet recording head according to claim 1, wherein only the heat-generating peripheral portion is arranged. 6. A plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors are formed on a substrate,
A substrate for an ink jet recording head, on which a protective film for protecting the heating resistor and the electrode wiring pattern for protecting them from ink is formed, a discharge port for discharging ink, and a liquid path communicating with the discharge port Wherein the heating resistor comprises a first heating resistor provided below the electrode wiring pattern connected to the heating resistor, the protection film and the electrode wiring pattern. An ink jet recording head comprising: a second heat generating resistor provided therebetween. 7. The ink jet recording head according to claim 6, wherein said electrode wiring is made of Al. 8. The ink jet recording head according to claim 6, wherein said protective film has a thickness of 200 to 700 nm. 9. The ink jet recording apparatus according to claim 6, wherein the first heating resistor is separated at a heating portion of the heating resistor and is arranged only in a peripheral portion of the electrode wiring pattern. head. 10. The first heating resistor according to claim 6, wherein a portion corresponding to a heat-generating central portion of a heat-generating portion of the heat-generating resistor is removed, and only a heat-generating peripheral portion is disposed. 3. The ink jet recording head according to item 1. 11. A plurality of heating resistors and an electrode wiring pattern electrically connected to the heating resistors are formed on a substrate, and these are protected from ink on the heating resistors and the electrode wiring patterns. A method for manufacturing an ink jet recording head, comprising: a substrate for an ink jet recording head on which a protective film is formed; an ejection port for ejecting ink; and a liquid path communicating with the ejection port. Forming a first heating resistor, and forming the electrode wiring pattern on the first heating resistor except for a heating portion of the heating resistor and connected to the first heating resistor. Covering the electrode wiring pattern with a second heating resistor; forming the protective film on the second heating resistor;
A method for manufacturing an ink jet recording head, comprising: 12. The method according to claim 11, wherein a film forming temperature in the step of forming the protective film is 400 ° C. or higher. 13. The method according to claim 11, wherein the protection film is formed by LPCVD. 14. The method according to claim 11, wherein said electrode wiring is made of Al. 15. The protective film has a thickness of 200 to 700 nm.
The method of manufacturing an ink jet recording head according to claim 11, wherein: 16. The ink jet recording apparatus according to claim 11, wherein the first heating resistor is separated at a heating portion of the heating resistor and is arranged only in a peripheral portion of the electrode wiring pattern. Head manufacturing method. 17. The first heat generating resistor according to claim 11, wherein a portion corresponding to a heat generating central portion in a heat generating portion of the heat generating resistor is removed, and only a heat generating peripheral portion is disposed. 3. The method for manufacturing an ink jet recording head according to item 1.