JP2014083772A - Liquid discharge head manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a liquid supply port having a good shape by a simple method on a silicon substrate of a liquid discharge head.SOLUTION: A liquid discharge head manufacturing method, in which includes a channel forming member for forming a liquid discharge port and a liquid channel and a silicon substrate for forming a liquid supply port to supply liquid to the liquid discharge port and the liquid channel, comprises a process to prepare the silicon substrate which has a first mask layer formed with an opening and the channel forming member for forming the liquid discharge port and the liquid channel on the first mask layer in a front surface side, and a second mask layer formed with an opening in a rear surface side, and a process forming a liquid supply port on the silicon substrate by supplying etching liquid from the opening formed in the first mask layer and the opening formed in the second mask layer and etching the silicon substrate.

Description

  The present invention relates to a method for manufacturing a liquid discharge head.

  A liquid discharge apparatus is known as an apparatus for recording an image by discharging liquid and landing on a recording medium such as paper. The liquid discharge apparatus has a liquid discharge head, and liquid is discharged from the discharge port of the liquid discharge head.

  As a method for manufacturing a liquid discharge head, Patent Document 1 discloses that a mold material that becomes a mold of a liquid flow path is formed on a substrate, the mold material is subsequently covered with a flow path forming member, and then the mold material is removed to form a liquid flow path. A method of forming is described. This method will be described with reference to FIG.

  First, as shown in FIG. 7A, a mask layer 108 is provided on the back side of the silicon substrate 101. An opening 109 is formed in the mask layer 108. A protective film 116 having no opening is formed on the surface side of the silicon substrate 101. Next, as illustrated in FIG. 7B, a flow path forming member 103 that forms a liquid discharge port and a liquid flow path is formed on the surface side of the silicon substrate 101. A mold 110 serving as a mold for the liquid flow path is formed in a portion that becomes the liquid flow path. Subsequently, as shown in FIG. 7C, the flow path forming member 103 is covered with a protective member 201. In this state, as shown in FIG. 7D, an etching solution is supplied from the opening 109 of the mask layer 108 on the back surface side, and the silicon substrate 101 is etched. The protection member 201 serves to protect the flow path forming member 103 from the etching solution. As the etching proceeds, the etching solution reaches the protective film 116 on the surface side as shown in FIG. The protective film 116 functions as an etching stop layer and suppresses the reaching of the etching solution to the flow path forming member 103. In this way, the liquid supply port 105 is formed in the silicon substrate 101, and the protective film 116 on the upper surface of the liquid supply port 105 is removed by dry etching as shown in FIG. Communicate to the side. Then, the protective member 201 is removed, and the mold member 110 is removed, whereby the liquid ejection head shown in FIG.

Japanese Patent Laid-Open No. 9-11479

  According to the method described in Patent Document 1, a liquid discharge head having a good shape can be manufactured. However, the opening width of the liquid supply port 105 on the front surface side of the silicon substrate 101 depends on the etching accuracy by the etching liquid and the protection. It is determined by the dry etching accuracy of the film 116. For this reason, high technology is required to control the opening width of the liquid supply port 105 on the surface side of the silicon substrate 101 with very high accuracy.

  For example, by providing a sacrificial layer such as aluminum that is more easily etched than the silicon substrate on the surface side of the silicon substrate, the opening width on the surface side of the liquid supply port can be controlled with high accuracy. However, in this case, the step of providing a sacrificial layer increases.

  In the method described in Patent Document 1, the etching solution is supplied only from the back side of the silicon substrate. Advanced technology is also required to supply the liquid.

  Therefore, the present invention provides a liquid discharge head capable of manufacturing a liquid supply port having a good shape by a simple method when a liquid supply port is formed in a silicon substrate by etching the silicon substrate with an etching solution. An object is to provide a manufacturing method.

  The above problems are solved by the present invention described below. That is, the present invention provides a liquid discharge head having a flow path forming member that forms a liquid discharge port and a liquid flow path, and a silicon substrate that forms a liquid supply port that supplies liquid to the liquid discharge port and the liquid flow path. A manufacturing method, comprising: a first mask layer having an opening formed on a front surface side; a flow path forming member that forms a liquid discharge port and a liquid flow path on the first mask layer; A silicon substrate having a second mask layer having an opening formed on the side, an etching solution formed from the opening formed in the first mask layer and the opening formed in the second mask layer; And a step of etching the silicon substrate to form a liquid supply port in the silicon substrate.

  According to the present invention, when a liquid supply port is formed on a silicon substrate by etching with an etchant, a liquid supply port having a good shape can be manufactured by a simple method.

FIG. 4 is a cross-sectional view of a head showing an example of a liquid discharge head manufactured by the present invention. FIG. 4 is a cross-sectional view of a head illustrating an example of a method for manufacturing a liquid discharge head according to the present invention. FIG. 4 is a cross-sectional view of a head illustrating an example of a method for manufacturing a liquid discharge head according to the present invention. FIG. 4 is a cross-sectional view of a head illustrating an example of a method for manufacturing a liquid discharge head according to the present invention. FIG. 4 is a cross-sectional view of a head illustrating an example of a method for manufacturing a liquid discharge head according to the present invention. FIG. 4 is a cross-sectional view of a head illustrating an example of a method for manufacturing a liquid discharge head according to the present invention. FIG. 10 is a head cross-sectional view illustrating an example of a conventional method for manufacturing a liquid discharge head.

  Hereinafter, modes for carrying out the present invention will be described.

  FIG. 1 is an example of a cross-sectional view of a liquid discharge head manufactured according to the present invention. The liquid discharge head 100 includes a silicon substrate 101 and a flow path forming member 103 that forms a liquid discharge port 104 and a liquid flow path 115. An energy generating element 102 is formed on the surface side of the silicon substrate 101. Examples of the energy generating element include a heat conversion element (heater) and a piezoelectric element. The energy generating element 102 may be in contact with the silicon substrate 101 or may have a portion that is separated from the silicon substrate 101 and floats in the air. An insulating layer is preferably provided between the silicon substrate 101 and the energy generating element 102. A first mask layer 106 is provided on the surface side of the silicon substrate 101 so as to cover the energy generating element 102. An opening is formed in the first mask layer 106. In addition, a second mask layer 108 is provided on the back surface side of the silicon substrate 101, and an opening is also formed in the second mask layer 108.

  The above-described first mask layer 106 is provided on the surface side of the silicon substrate 101, and the flow path forming member 103 that forms the liquid discharge port 104 and the liquid flow path 115 is formed on the first mask layer. Yes. A liquid discharge port 104 is formed at a position facing the energy generation element 102 of the flow path forming member 103.

  A liquid supply port 105 is formed in the silicon substrate 101. The liquid supply port 105 is opened by an opening 107 on the front surface side and an opening 109 on the back surface side of the silicon substrate 101, and penetrates the silicon substrate 101 in the vertical direction. The opening 107 on the front surface side and the opening 109 on the back surface side correspond to the opening of the first mask layer 106 and the opening of the second mask layer 108, respectively. The liquid supply port 105 supplies a liquid to the liquid channel 115 and the liquid discharge port 104. The liquid supplied from the liquid supply port 105 to the liquid flow path 115 is given energy generated from the energy generating element 102, and the liquid is discharged from the liquid discharge port 104 to record an image.

  Next, a method for manufacturing a liquid discharge head according to the present invention will be described with reference to an embodiment.

<Embodiment 1>
First, as shown in FIG. 2A, a silicon substrate having a first mask layer 106 with an opening 107 formed on the front surface side and a second mask layer 108 with an opening 109 formed on the back surface side. 101 is prepared. As the silicon substrate 101, it is preferable to use a substrate whose front and back crystal orientations are (100), that is, a so-called (100) substrate. The first mask layer and the second mask layer are preferably resistant to an etching solution used when the silicon substrate 101 is etched later. The first mask layer and the second mask layer are formed using, for example, a plasma CVD method. The opening of the first mask layer and the second mask layer is formed by the following method, for example. First, a photosensitive resist (photosensitive resin or the like) is applied on the mask layer by spin coating or the like. Next, the applied photosensitive resist is patterned by photolithography to form an opening pattern in the photosensitive resist. Then, an opening is formed in the mask layer by dry etching the mask layer using the photosensitive resist having the opening pattern as a mask.

Next, an energy generating element, its wiring, and the like (not shown) are formed on the surface side of the silicon substrate 101, and a mold material 110 serving as a liquid flow path mold is formed. The mold material 110 may be any material that can be removed later, but is preferably formed of a positive photosensitive resin. Examples of the material of the mold member 110 include polyimide and polymethylisopropenyl ketone. A composition containing these resins is applied onto the surface of the silicon substrate and patterned to form the mold 110. For example, a mask may be formed on the coated composition and patterned by performing anisotropic dry etching using O ₂ gas or the like, or when the mold member 110 is formed of a photosensitive resin. The patterning material 110 may be patterned by photolithography.

  Subsequently, the flow path forming member 103 is formed so as to cover the mold member 110. It is preferable that the flow path forming member 103 is resistant to an etching solution used when the silicon substrate 101 is etched later. The flow path forming member 103 is formed using, for example, a plasma CVD method.

  Thereafter, a resist is applied on the flow path forming member, and a pattern is formed on the resist by photolithography. Subsequently, the flow path forming member is dry-etched using the patterned resist as a mask to form a liquid discharge port 104 in the flow path forming member as shown in FIG. The liquid discharge port 104 may be formed by exposing and developing the flow path forming member by photolithography.

Next, as shown in FIG. 2C, the mold material 110 is removed to form a liquid channel 115. The mold material 110 is removed by isotropic dry etching using, for example, O ₂ gas. The first mask layer 106 and the flow path forming member 103 are preferably made of materials that are difficult to be etched by the etching at this time.

  After removing the mold material 110 in this way, the silicon substrate 101 having the flow path forming member 103 is immersed in an etching solution. The flow path forming member 103 may not be covered with a protective member or the like. When immersed in the etching solution, the etching solution is supplied from the back surface side of the silicon substrate 101 through the opening 109 of the second mask layer 108. At substantially the same time, an etching solution is also supplied from the surface side of the silicon substrate 101 through the opening 107 of the first mask layer 106. This is because the liquid discharge port 104 and the liquid flow channel 115 are formed in the flow channel forming member 103, and the etching liquid immediately reaches the opening 107 through the liquid discharge port and the liquid flow channel. Examples of the etching solution include a TMAH solution and a KOH solution. The etching of the silicon substrate 101 is preferably anisotropic etching using these etching solutions. When the etchant is supplied from both sides of the silicon substrate, the silicon substrate is etched from both the front side and the back side, resulting in a state as shown in FIG. By continuing the etching as it is, etching from both sides of the silicon substrate is connected, and a liquid supply port 105 is formed in the silicon substrate 101 as shown in FIG. In the case where the etching is anisotropic etching, the etching is substantially stopped when all the etched surfaces are (111) planes. That is, when both the part of the supply port formed by etching from the front surface side and the part of the supply port formed by etching from the back side are in the form in which the (111) plane is exposed, the etching stops. It is necessary to avoid this situation. Therefore, in consideration of this point, the opening width of the opening 107 of the first mask layer 106 and the opening width of the opening 109 of the second mask layer 108 are set. Here, the width of the opening 109 on the back surface side is a, the width of the opening 107 on the front surface side is b, and the thickness of the silicon substrate is c. When the front and back surfaces of the silicon substrate are (100) planes, (a / 2 + b / 2) × tan 54.7> c.

  In the present invention, regarding the opening of the liquid supply port 105, the opening on the back surface side of the silicon substrate is controlled by the opening 109 of the second mask layer 108, and the opening on the front surface side is controlled by the opening 107 of the first mask layer 106. . In this manner, the liquid supply port can be formed by a simple method that does not use a sacrificial layer or the like, and the shape of the liquid supply port to be formed can be made highly accurate.

  The first mask layer 106 and the flow path forming member 103 are preferably resistant to an etchant used during etching. For this reason, these members (the first mask layer and the flow path forming member) are preferably made of silicon, carbon, or the like. With regard to this point, the present inventors have further studied, and found that the resistance to the etching solution is greatly improved by increasing the carbon content to silicon in these members. Specifically, when these members contain silicon and carbon, the silicon content ratio of the member is X (atom%), and the carbon content ratio is Y (atom%), Y / X is 0.001. It has been found that the above is preferable. Y / X is more preferably 0.01 or more, further preferably 0.05 or more and 0.1 or more. Further, from the viewpoint of film formability, Y / X is preferably 10 or less. Silicon and carbon in the member are preferably present as silicon carbide (SiC). The total amount of silicon and carbon, that is, X + Y is preferably 50 or more. These members may be composed only of silicon and carbon, in which case X + Y = 100.

  These members preferably contain nitrogen, and preferably contain silicon carbonitride (SiCN) together with silicon and carbon. By containing nitrogen, the insulating properties of the member can be enhanced. When the content ratio of nitrogen in the member is Z (atom%), X + Y + Z is preferably more than 50. The member may be composed only of silicon, carbon, and nitrogen. In that case, X + Y + Z = 100.

As long as the second mask layer 106 is also a mask layer, it is naturally preferable that the second mask layer 106 be resistant to an etching solution used during etching. For example, the second mask layer 106 is preferably formed of SiC or SiCN. In addition, it is also preferable to form with SiO ₂ or polyether amide.

The ratios of silicon and carbon in the first mask layer, the second mask layer, and the flow path forming member can be controlled by appropriately adjusting the conditions of the plasma CVD method. For example, when depositing silicon carbide, SiH ₄ gas flow rate: 80 sccm to 1 slm, CH ₄ gas flow rate: 10 sccm to 5 slm, HRF power: 250 W to 900 W, LRF power: 8 W to 500 W, pressure: 310 Pa to 700 Pa, temperature: It adjusts suitably according to the thickness of a member, and the content rate of a silicon and carbon from the film-forming conditions of 300 to 450 degreeC. When silicon carbonitride is formed, SiH ₄ gas flow rate: 80 sccm to 1 slm, NH ₃ gas flow rate: 14 sccm to 400 sccm, N ₂ gas flow rate: 0 slm to 10 slm, CH ₄ gas flow rate: 10 sccm to 5 slm, HRF power: 250 W ˜900 W, LRF power: 8 W to 500 W, pressure: 310 Pa to 700 Pa, temperature: 300 ° C. to 450 ° C.

  The fact that resistance to the etching solution is greatly improved by increasing the content ratio of carbon to silicon in the member will be described below using a flow path forming member as an example.

  A mold material is formed of polyimide on a silicon substrate, and SiC, SiCN, SiO, and SiN are formed by plasma CVD so as to cover the mold material, thereby forming a flow path forming member. Assume that the silicon content in the member is X (atom%), the carbon content is Y (atom%), and the nitrogen content in the member is Z (atom%). Next, the formed flow path forming member is dry-etched to form a liquid discharge port in the flow path forming member.

The substrate on which these flow path forming members are formed is immersed in pigment ink (70 ° C.) of pH 8.5 for one month, and the shapes of the flow path forming members and the liquid discharge ports are observed with a microscope, and evaluated according to the following criteria. went.
(Shape of flow path forming member)
1; Almost no deformation of the flow path forming member is observed.
2: Deformation of the flow path forming member is observed.
3; All or most of the flow path forming member has disappeared.
(Liquid discharge port shape)
1: Deformation of the liquid discharge port is hardly seen.
2: Deformation of the liquid discharge port is slightly observed.
3: The liquid discharge port is deformed to such an extent that it does not exist.

  These evaluation results are shown in Tables 1 and 2 together with the thickness of the mold material, the thickness of the flow path forming member (thickness on the mold material), and the diameter of the liquid discharge port.

<Embodiment 2>
In the above-described method, the supply port is formed in the silicon substrate using only the etching solution. However, a method may be used in which a non-through hole is first formed in the silicon substrate and then etching is performed using the etching solution. An embodiment using this method will be described with reference to FIG.

  First, FIGS. 3A and 3B are the same as FIGS. 2A and 2B of the first embodiment.

  Subsequently, after removing the mold member 110, a non-through hole 111 is formed in the silicon substrate from the opening 109 of the second mask layer 108. In the cross section shown in FIG. 3C, two non-through holes 111 are formed. The non-through hole can be formed by laser irradiation, dry etching, or the like, but is preferably formed by laser irradiation.

  Next, as shown in FIG. 3D and FIG. 3E, the liquid supply port 105 is formed with an etching solution. The arrangement, number, depth, and the like of the non-through holes are adjusted so that the etching from the non-through holes reaches a part of the liquid supply port. Etching with the etchant is preferably anisotropic etching.

  By forming the non-through hole as in this embodiment, the opening width on the substrate surface side can be stabilized. The reason is considered as follows.

  When the non-through hole is not formed, the liquid supply port has a (111) surface from the back surface side to the front surface side. At this time, if there is a crystal defect in the silicon substrate in the course of etching, the opening width on the surface side widens. However, if etching is performed after forming the non-through hole, the (111) plane can be reduced, and the opening width on the surface side can be stabilized.

  Moreover, the etching time can also be shortened by forming the non-through hole before etching with the etching solution.

<Embodiment 3>
There are other methods that use a non-through hole to form the liquid supply port. The example is demonstrated using FIG.4 and FIG.5.

  First, the method shown in FIG. 4 will be described. 4A and 4B are the same as FIGS. 2A and 2B of the first embodiment.

  Subsequently, after removing the mold member 110, a non-through hole 111 is formed in the silicon substrate from the opening 109 of the second mask layer 108. Further, the non-through hole 112 is also formed from within the opening 107 of the first mask layer 106. That is, as shown in FIG. 4C, a non-through hole 111 is formed in the silicon substrate 101 from the back surface side, and a non-through hole 112 is formed from the front surface side. Either the non-through hole 111 or the non-through hole 112 may be formed first or simultaneously. The non-through hole 111 may be formed by laser irradiation as described above, or may be formed by dry etching. However, the non-through hole 112 is formed by laser irradiation. This is because the flow path forming member 103 formed on the surface side of the substrate 101 is not damaged. Since the laser irradiating the surface side needs to pass through the flow path forming member 103, the wavelength needs to be appropriate. For example, when the flow path forming member 103 is formed of SiC or SiCN, a laser having a wavelength of 500 nm or more is irradiated.

  After that, as shown in FIGS. 4D and 4E, etching with an etchant is performed to form the liquid supply port 105. By forming the non-through holes from both sides in this way, the formation of the liquid supply port 105 can be further accelerated.

<Embodiment 4>
Next, the method shown in FIG. 5 will be described. FIGS. 5A and 5B are the same as FIGS. 2A and 2B of the first embodiment.

  Subsequently, as shown in FIG. 5C, after removing the mold material 110, a non-through hole 111 is formed in the silicon substrate from the opening 109 of the second mask layer 108. Further, an altered region 113 in which silicon crystal defects continuously exist is formed from the opening 107 of the first mask layer 106. In the altered region 113, the crystal structure of silicon is broken, and etching proceeds very quickly. The altered region 113 is formed by converging the focal point of the laser and performing laser processing with multiphoton absorption. For example, laser light of a fundamental wave (wavelength 1060 nm) of a YAG laser is used, and the power and frequency of the laser light are set to appropriate values. The laser beam that can be used for processing is not limited as long as it can absorb multiphotons with respect to silicon which is a material of the substrate. For example, a femtosecond laser can be used. Further, when the flow path forming member 103 is formed of SiC or SiCN, the wavelength of the laser light is set to 500 nm or more.

  After that, as shown in FIGS. 5D and 5E, etching with an etchant is performed to form the liquid supply port 105. Thus, by performing laser irradiation from both sides, the formation of the liquid supply port 105 can be further accelerated. Further, if the altered region is formed, unlike the normal laser irradiation as shown in FIG. 4, almost no debris (debris) is generated on the surface side of the substrate. Therefore, even if the laser that forms the altered region on the surface side is irradiated, the flow path forming member 103 is not greatly affected.

<Embodiment 5>
A method of using a through hole instead of a non-through hole for forming the liquid supply port will be described with reference to FIG. 6A and 6B are the same as FIGS. 2A and 2B of the first embodiment.

  Subsequently, as shown in FIG. 6C, after the mold member 110 is removed, the opening 107 of the first mask layer 106 and the opening 109 of the second mask layer 108 penetrate through these openings. Hole 114 is formed. The through hole 114 is preferably formed by laser irradiation. In the case of laser irradiation, since it is necessary to pass through the flow path forming member 103, it is necessary to irradiate a laser having an appropriate wavelength. For example, when the flow path forming member 103 is formed of SiC or SiCN, it is preferable to irradiate a laser having a wavelength of 500 nm or more.

  After that, as shown in FIGS. 6D and 6E, etching with an etchant is performed to form the liquid supply port 105. According to this method, the formation of the liquid supply port 105 can be further accelerated. Further, the shape of the liquid supply port 105 can be further stabilized, and in particular, the opening width on the surface side of the silicon substrate can be controlled with very high accuracy.

Claims (14)

A method for manufacturing a liquid discharge head, comprising: a flow path forming member that forms a liquid discharge port and a liquid flow path; and a silicon substrate that forms a liquid supply port that supplies liquid to the liquid discharge port and the liquid flow path. ,
A first mask layer having an opening formed on the front surface side and a flow path forming member that forms a liquid discharge port and a liquid flow channel on the first mask layer, and the opening is formed on the back surface side Providing a silicon substrate having a second mask layer formed;
Etching the silicon substrate by supplying an etching solution from the opening formed in the first mask layer and the opening formed in the second mask layer, and forming a liquid supply port in the silicon substrate; ,
A method of manufacturing a liquid discharge head, comprising:   The flow path forming member contains silicon and carbon. When the silicon content rate of the flow path forming member is X (atom%) and the carbon content rate is Y (atom%), Y / X is 0.00. The method for manufacturing a liquid discharge head according to claim 1, wherein the liquid discharge head is 001 or more.   The method of manufacturing a liquid ejection head according to claim 2, wherein the Y / X is 0.01 or more.   The method of manufacturing a liquid ejection head according to claim 2, wherein Y / X is 0.05 or more.   The method for manufacturing a liquid discharge head according to claim 2, wherein the Y / X is 0.1 or more.   The method of manufacturing a liquid discharge head according to claim 1, wherein the flow path forming member contains nitrogen.   The method for manufacturing a liquid discharge head according to claim 1, wherein the flow path forming member contains silicon carbonitride.   The first mask layer contains silicon and carbon. When the silicon content of the first mask layer is X (atom%) and the carbon content is Y (atom%), Y / X is It is 0.001 or more, The manufacturing method of the liquid discharge head of any one of Claims 1-7.   The method of manufacturing a liquid ejection head according to claim 1, wherein the first mask layer contains nitrogen.   10. The non-through hole is formed in the silicon substrate from the opening of the second mask layer before the step of supplying the etching solution and etching the silicon substrate. Manufacturing method of liquid discharge head.   Before the step of supplying the etching solution and etching the silicon substrate, a laser beam that passes through the flow path forming member is irradiated to form a non-through hole in the silicon substrate from the opening of the first mask layer. The manufacturing method of the liquid discharge head of any one of Claims 1-10.   Before the step of supplying the etching solution and etching the silicon substrate, a laser beam that passes through the flow path forming member is irradiated to form an altered region in the silicon substrate from the opening of the first mask layer. Item 11. The method for producing a liquid ejection head according to any one of Items 1 to 10.   10. The through hole is formed in the silicon substrate by irradiating a laser that passes through the flow path forming member before the step of supplying the etching solution and etching the silicon substrate. A manufacturing method of a liquid discharge head given in 2.   The method of manufacturing a liquid ejection head according to claim 11, wherein the wavelength of the laser that passes through the flow path forming member is 500 nm or more.

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