JP4721465B2 - Recording head and manufacturing method of recording head - Google Patents

Description

  The present invention relates to a recording head and a manufacturing method of the recording head.

  Conventional ink jet recording heads can form and discharge fine ink droplets by reducing the discharge port for discharging ink. In this case, in order to secure the ink supply amount, it is necessary to make the cross-sectional area of the liquid flow path larger than the cross-sectional area of the discharge port, and dust mixed in the ink may reach the vicinity of the discharge port together with the ink. When the dust reaches the vicinity of the ejection port, the dust causes the ink ejection direction to deviate from a predetermined direction, or the ejection port is blocked to prevent the ink from protruding.

  Therefore, it has been proposed to provide a filter in the liquid flow path in order to prevent dust from reaching the vicinity of the ejection port while securing the ink supply amount.

  In Patent Document 1, as shown in FIG. 3 of Patent Document 1, a membrane filter structure 16 including a patterned SiN film 4 and an adhesion improving layer 7 is provided on the ink supply port 13 in the Si substrate 21. Is described.

In Patent Document 2, as shown in FIG. 1F of Patent Document 2, a filter including a patterned SiO ₂ film 3 and a patterning mask layer 6 is provided below an ink supply port 11 in a semiconductor substrate 10. It is described that it is provided.

In Patent Document 3, as shown in FIG. 1B of Patent Document 3, a supply port constituted by a plurality of through holes 5 communicating with the liquid flow path 2 and the ink supply port 3 in the substrate 8A. It is described that a filter 1 is provided.
JP 2005-178364 A JP 2006-168141 A JP 2006-130742 A S. Yamamoto, T. Suzuki, O. Nkao, H. Misimura, M. Sato, Fujikura Technical Review No. 101, p73, 2001

  In the technique described in Patent Document 1, the membrane filter structure 16 is formed outside the Si substrate 21.

  In the technique described in Patent Document 2, the filter is formed outside the semiconductor substrate 10.

  In the technique described in Patent Document 3, as shown in FIG. 2B of Patent Document 3, anisotropic dry etching such as RIE is performed from the surface 10 of the substrate 8A using a positive resist mask to form a through hole. 5, a vertically long hole 12 is formed. Thereafter, as shown in FIG. 2D of Patent Document 3, a meltable resin 13 is embedded in the holes 12. Then, as shown in FIG. 3G of Patent Document 3, by performing crystal anisotropic wet etching using an etchant from the back surface of the substrate 8 </ b> A, the resin 13 embedded in the holes 12 becomes the ink supply port 3. It is formed so as to protrude inward. Thereafter, the resin 13 is dissolved and removed to form the supply port filter 1 including the plurality of through holes 5 shown in FIG.

  An object of the present invention is to provide a filter portion having a structure that can be manufactured by a simple manufacturing process in the vicinity of a surface in a semiconductor substrate in a recording head.

  The recording head according to the first aspect of the present invention is a recording head that discharges the liquid from the discharge port by applying thermal energy to the liquid, and the first liquid supply that supplies the liquid to the discharge port A flow path, a second liquid supply flow path for supplying the liquid to the first liquid supply flow path, and the second liquid supply flow path and the first liquid supply flow path. And a semiconductor substrate including the filter unit, wherein the filter unit removes foreign matter from the liquid supplied by the first liquid supply channel, and removes the liquid from which the foreign matter has been removed from the first liquid. It has a plurality of through holes arranged to pass through the supply flow path, and is formed of a semiconductor having impurities at a higher concentration than the periphery of the filter portion in the semiconductor substrate.

  A recording head manufacturing method according to a second aspect of the present invention is a recording head manufacturing method in which thermal energy is applied to a liquid to discharge the liquid from an ejection port, and the ejection on the surface side of a semiconductor substrate is performed. A first step of implanting impurities in a mesh pattern in a first region to be below the outlet, and a second region continuous from a part of the back surface of the semiconductor substrate to the first region, By selectively etching using an etchant having an etching selection ratio according to the concentration of impurities, a second liquid supply channel is formed, and a region in the first region where the impurity is not implanted is formed. A second step of forming a filter portion having the mesh pattern by selectively etching using the etchant; and The liquid spent, characterized in that the first liquid supply channel for supplying to the discharge port and a third step of forming above the semiconductor substrate.

  According to the present invention, in the recording head, a filter portion having a structure that can be manufactured by a simple manufacturing process can be provided in the vicinity of the surface in the semiconductor substrate.

  A recording head 100 according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of a recording head 100 according to the first embodiment of the present invention. FIG. 1A is a diagram illustrating a cross-sectional configuration of the recording head 100. FIG. 1B is a diagram illustrating a layout configuration of the recording head 100.

  The recording head 100 causes the liquid to be ejected from the ejection port 30 by applying thermal energy to the liquid. The liquid is, for example, ink. The recording head 100 can be applied to, for example, an apparatus used for manufacturing a DNA chip, an organic transistor, a color filter, and the like. Further, the recording head 100 can be applied to an ink jet printer that deposits droplets on a recording medium (for example, paper).

  The recording head 100 includes a semiconductor substrate 10 and a first liquid supply channel 20. The semiconductor substrate 10 is provided with a flow path through which the liquid passes. The first liquid supply channel 20 is disposed above the semiconductor substrate 10 and supplies the liquid that has passed through the channel in the semiconductor substrate 10 to the discharge port 30.

  The semiconductor substrate 10 is formed of a semiconductor whose main component is silicon. The semiconductor substrate 10 includes a second liquid supply channel 11, a main body portion 12, a filter portion 13, and an electrothermal conversion element 14.

  The second liquid supply channel 11 is supplied with liquid from below and supplies the liquid to the first liquid supply channel 20. The second liquid supply channel 11 has an upper cross-sectional area CA1 smaller than a lower cross-sectional area CA2. The side surface of the second liquid supply channel 11 is a <100> plane or a <110> plane of silicon. As a result, the pressure of the liquid supplied from below the second liquid supply channel 11 rises when flowing from the lower part of the second liquid supply channel 11 to the upper part of the second liquid supply channel 11. .

  As will be described later, the second liquid supply channel 11 is a crystal using a chemical solution for the second region AR2 in the semiconductor substrate 10 using the pattern of the oxide film 7 formed on the lower surface of the semiconductor substrate 10 as a mask. It is formed by performing anisotropic etching. The second area AR2 is an area extending from a part of the back surface 10b of the semiconductor substrate 10 so as to continue to the first area AR1 described later.

  The main body 12 surrounds the second liquid supply channel 11. As will be described later, the main body 12 is a portion that has not been etched when anisotropic etching using a chemical solution is performed on the semiconductor substrate 10.

  The filter unit 13 is disposed between the first liquid supply channel 20 and the second liquid supply channel 11 so as to be in contact with the upper part of the second liquid supply channel 11. The filter unit 13 removes foreign matters contained in the liquid supplied to the second liquid supply channel 11. Thereby, compared with the case where the through-hole in a filter is distribute | arranged so that the side surface of a 2nd liquid supply flow path and a 1st liquid supply flow path may be connected, the thickness of a filter part can be restrained thinly. Therefore, the pressure loss of the liquid that passes through the filter unit 13 can be reduced.

  The filter portion 13 includes a plurality of through holes 13a and a frame portion 13b.

  The plurality of through holes 13a are arranged so as to remove foreign substances by allowing the liquid supplied to the second liquid supply channel 11 to pass therethrough. The foreign object is, for example, garbage. For example, as shown in FIG. 1B, each of the plurality of through holes 13a has a substantially rectangular shape in a top view, and is arranged at regular intervals two-dimensionally in the first region AR1. The first region AR <b> 1 is a region that should become the filter portion 13 on the surface 10 a side of the semiconductor substrate 10.

Here, when the average opening area of each of the plurality of through holes 13a is OA1, the opening area of the discharge port 30 is OA2, and the total opening area of the plurality of through holes 13a is SOA,
OA1 ≦ OA2 (Formula 1)
And OA2 <SOA ... Formula 2
Holds. That is, as shown in Equation 1, the dust filtering effect can be improved by reducing the average opening area of each of the plurality of through holes 13a to OA1. Further, as shown in Expression 2, the total opening area of the plurality of through holes 13a is sufficiently increased with respect to the SOA and the opening area of the discharge port 30 with respect to OA2, so that a sufficient amount of liquid is supplied to the discharge port 30. can do.

  The frame portion 13b is disposed so as to surround the plurality of through holes 13a, and is formed of a semiconductor having impurities at a higher concentration than the main body portion 12. That is, the filter unit 13 is formed of a semiconductor having impurities at a higher concentration than the periphery of the filter unit in the semiconductor substrate 10. The impurity which the flame | frame part 13b has is a boron (boron), for example. Thereby, as will be described later, the filter unit 13 has a structure that can be manufactured by a simple manufacturing process.

  The frame part 13b has a mesh pattern. That is, the filter portion 13 extends in a lattice shape along the surface 10a of the semiconductor substrate 10 (see FIG. 1B). As a result, the depth of the plurality of through holes 13a surrounded by the frame portion 13b can be easily reduced. The depth of each of the plurality of through holes 13a is, for example, 5 μm or less. That is, the thickness of the filter unit 13 is 5 μm or less. Thereby, the pressure loss of the liquid which passes the filter part 13 can be reduced.

  Here, if the depth of each of the plurality of through holes 13a is deeper than 5 μm, the pressure received by the plurality of through holes 13a when the inner diameters of the plurality of through holes 13a are made large enough to remove foreign matters. Loss becomes significant.

  The impurity may be any one of phosphorus, arsenic, and antimony.

  Further, among the plurality of through holes 13a, the through hole 13a1 in contact with the main body 12 has an upper cross-sectional area smaller than a lower cross-sectional area. The through hole 13a1 is a silicon <100> surface or <110> surface in contact with the main body 12. Thus, the pressure of the liquid supplied from below the through hole 13a1 increases when flowing from the lower part of the through hole 13a1 to the upper part of the through hole 13a1.

  A plurality of electrothermal conversion elements 14 are arranged in a third region AR3 below the discharge port 30 and adjacent to the filter unit 13 so that thermal energy acts on the liquid supplied to the discharge port 30. Thereby, it is possible to apply a sufficient pressure to the liquid supplied to the discharge port 30 to be discharged from the discharge port 30.

  For example, the third AR3 region is arranged on both sides of the first region AR1. For example, as shown in FIG. 1B, the plurality of electrothermal conversion elements 14 are substantially rectangular in top view, and are arranged at a constant pitch in the third region AR3 arranged in two rows. The third region AR3 is a region adjacent to the first region AR1 on the surface 10a side of the semiconductor substrate 10.

  The first liquid supply channel 20 communicates the plurality of through holes 13 a and the discharge ports 30, and supplies the liquid that has passed through the filter unit 13 to the discharge ports 30. The first liquid supply channel 20 includes a channel 4a, a channel 5a, and a channel 6a.

  The flow path 4 a is an opening along the plurality of through holes 13 a in the surface protective film 4 disposed on the semiconductor substrate 10. The surface protective film 4 is made of, for example, silicon nitride or silicon oxide. The flow path 4a supplies the liquid that has passed through the filter unit 13 to the flow path 5a.

  The flow path 5 a is an opening along the flow path 4 a in the adhesion improving layer 5 disposed on the surface protective film 4. The adhesion improving layer 5 is made of, for example, HIMAL. The channel 5a supplies the liquid that has passed through the channel 4a to the channel 6a.

  The flow path 6 a is an opening that extends along the surface of the semiconductor substrate 10 in the coated photosensitive resin 6 disposed on the adhesion improving layer 5. The flow path 6 a supplies the liquid that has passed through the flow path 5 a to the discharge port 30. The discharge port 30 is an opening extending perpendicularly to the surface of the semiconductor substrate 10 in the coated photosensitive resin 6 disposed on the adhesion improving layer 5.

  Thus, according to the present embodiment, in the recording head 100, the filter unit 13 having a structure that can be manufactured by a simple manufacturing process can be provided in the vicinity of the surface 10a in the semiconductor substrate 10. Further, in the recording head 100 according to the present embodiment, the filter unit 13 formed in the semiconductor substrate 10 has the second liquid between the first liquid supply channel 20 and the second liquid supply channel 11. It is arranged in contact with the upper part of the supply flow path 11. Thereby, compared with the case where a filter is arranged so that the side of the 2nd liquid supply channel and the 1st liquid supply channel may be connected, since the thickness of a filter part can be held down, filter The pressure loss of the liquid passing through the portion 13 can be reduced. That is, even when the filter unit is provided inside the semiconductor substrate, the pressure loss that the liquid passing through the filter unit receives can be reduced.

  Next, a method for manufacturing the recording head 100 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a process cross-sectional view illustrating the method of manufacturing the recording head 100 according to the first embodiment of the present invention.

  In the step shown in FIG. 2A, a semiconductor substrate 10i is prepared.

  In the step shown in FIG. 2B, impurity ions are implanted into the first region AR1 in the semiconductor substrate 10i in a mesh pattern. The first area AR1 is an area that should be below the discharge port 30 on the surface 10ia side of the semiconductor substrate 10i and should be the filter section 13. The impurity ions are, for example, boron ions. The depth of boron ions implanted into the first region AR1 (depth of the first region AR1) is preferably within 5 μm from the surface 10ia.

  The impurity ions may be any one of phosphorus ions, arsenic ions, and antimony ions.

The concentration of boron ions implanted into the first region AR1 is desirably 10 ¹⁹ atm / cm ³ or more. As described in Non-Patent Document 1, an etching rate rapidly decreases below this concentration, which is not desirable for processing.

  Note that impurities may be implanted into the first region AR1 in a mesh pattern by using a solid phase diffusion method instead of the ion implantation method.

  Next, an oxide film 7i is formed on the back surface 10ib of the semiconductor substrate 10i.

  In the step shown in FIG. 2C, predetermined impurity ions are formed in the third region AR3 in the semiconductor substrate 10i in a mesh pattern (specifically, a lattice pattern) as shown in FIG. Is injected to form the electrothermal conversion element 14. The third region AR3 is a region adjacent to the first region AR1 on the front surface 10ia side (front surface side) of the semiconductor substrate 10i. In addition, a driver IC (not shown) for driving the electrothermal transducer 14 is formed in a region adjacent to the third region AR3 on the surface 10ia side of the semiconductor substrate 10i on the opposite side to the first region AR1. .

  Next, a surface protective film 4i is formed so as to cover the surface 10ia of the semiconductor substrate 10i. The surface protective film 4i protects the electrothermal conversion element 14 and the driver IC from the liquid. The surface protective film 4 is formed of silicon nitride or silicon oxide using, for example, a plasma CVD method.

  In the step shown in FIG. 2D, the adhesion improving layer 5 and the adhesion improving layer 5j are formed by applying a resin to the front surface 10ia and the back surface 10ib of the semiconductor substrate 10, patterning with a resist, and performing ashing. Form. The adhesion improving layer 5 and the adhesion improving layer 5j are formed using, for example, a resin ODUR made by Tokyo Ohka.

  Next, a shape corresponding to the first liquid supply flow path 20 is formed in the region to be the first liquid supply flow path 20 with a soluble resin 40.

  Furthermore, by applying the covering photosensitive resin 6 on the adhesion improving layer 5 and the resin 40, a structure corresponding to the nozzle structure, that is, the first liquid supply channel 20 and the discharge port 30 is formed.

  In the step shown in FIG. 2E, the patterned oxide film 7 is formed by etching the oxide film 7i using the dry etching method or the wet etching method with the pattern of the adhesion improving layer 5j as a mask.

  In the step shown in FIG. 2F, the second liquid supply channel 11 and the plurality of through holes 13a are formed by performing crystal anisotropic etching with a chemical solution from the back surface 10ib side of the semiconductor substrate 10i.

  Specifically, the second liquid supply channel 11 is formed by selectively etching the second region AR2 using an etchant using the pattern of the oxide film 7 and the adhesion improving layer 5j as a mask. The second area AR2 is an area extending from a part of the back surface 10ib of the semiconductor substrate 10i so as to continue to the first area AR1. This etchant has an etching selectivity according to the concentration of impurities. That is, this etchant has a higher etching selectivity in a region where impurities are not implanted than in a region where impurities are implanted in a semiconductor. The etchant is preferably, for example, TMAH (Tri-methyl ammonium hydrate) or KOH. At this time, since the semiconductor substrate 10i is etched along, for example, the crystal orientation of silicon, the side surface of the second liquid supply channel 11 becomes the <100> plane or the <110> plane of silicon.

  Thereafter, the first region AR1 is continuously etched using the above etchant. Thereby, a plurality of through holes 13a are formed by selectively etching the region in the first region AR1 where the impurity ions are not implanted using the above etchant. In addition, the frame portion 13b is formed by leaving the region into which the impurity ions are implanted in the first region AR1 without being etched. That is, the filter unit 13 having a mesh pattern (specifically, a lattice pattern) is formed.

  In the step shown in FIG. 2G, the resin 40 filling the region to be the first liquid supply channel 20 is removed by dissolving it with a predetermined solvent, whereby the flow in the first liquid supply channel 20 is removed. A channel 5a and a channel 6a are formed. Further, the adhesion improving layer 5j is removed by a dry etching method, and the portion exposed by the through hole 13a in the surface protective film 4 is selectively removed to thereby remove the channel 4a in the first liquid supply channel 20. Form.

  Then, an ink supply member (not shown) is attached to the back surface 10b side of the semiconductor substrate 10, that is, the back surface 7b of the oxide film 7, thereby completing the recording head.

  According to this embodiment, the second liquid supply channel and the filter unit are continuously etched by etching the second liquid supply channel and the plurality of through holes in the semiconductor substrate using the same chemical solution. Can be formed. Accordingly, the second liquid supply channel and the filter unit are formed as compared with the case of forming a filter having a through hole that communicates the side surface of the second liquid supply channel and the first liquid supply channel. Therefore, the number of steps for reducing the number of steps can be reduced.

  In addition, since the second liquid supply channel and the filter unit can be formed continuously, the second liquid supply channel and the filter unit are not easily affected by dust generation in the manufacturing apparatus. Thereby, the manufacturing yield of the recording head can be improved.

  Furthermore, since the filter portion is formed not inside the semiconductor substrate but inside, the filter portion is not peeled off from the surface of the semiconductor substrate.

  A recording head 200 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a configuration of a recording head 200 according to the second embodiment of the present invention. FIG. 3A is a diagram illustrating a cross-sectional configuration of the recording head 200. FIG. 3B is a diagram illustrating a layout configuration of the recording head 200. Below, it demonstrates centering on a different part from 1st Embodiment.

  The recording head 200 according to the second embodiment of the present invention further includes a metal film 240.

  As shown in FIG. 3A, the metal film 240 is disposed between the discharge port 30 and the electrothermal conversion element 14 and between the adhesion improving layer 5 and the surface protective film 204. The metal film 240 is made of Ta, for example. As shown in FIG. 3B, the metal film 240 continuously covers the plurality of electrothermal transducers 14 in the third region AR3 when viewed from a direction perpendicular to the surface 10a of the semiconductor substrate 10. Are formed to extend. Thereby, since the stress which cavitation (bubble) exerts on the surface protective film 204 when the liquid is discharged from the discharge port 30 can be reduced, the occurrence of cracks in the surface protective film 204 can be suppressed. For this purpose, it is effective that the metal film 240 is made of Ta. As a result, the required durability can be satisfied even if the thickness of the surface protective film 204 is reduced. The surface protective film 204 can have a thickness of 3000 mm, for example.

  Further, as shown in FIG. 4, the manufacturing method of the recording head 200 differs from the first embodiment in the following points. FIG. 4 is a process cross-sectional view illustrating the method for manufacturing the recording head 200 according to the second embodiment of the present invention.

  In the step shown in FIG. 4C1, after the surface protective film 204i is formed, a metal layer to be the metal film 240 is formed on the surface protective film 204i by a sputtering method. The metal layer is made of Ta, for example. Then, the metal layer 240 is formed by patterning the metal layer into the pattern shown in FIG.

1 is a diagram illustrating a configuration of a recording head 100 according to a first embodiment of the present invention. FIG. 6 is a process cross-sectional view illustrating the method for manufacturing the recording head 100 according to the first embodiment of the invention. FIG. 6 is a diagram illustrating a configuration of a recording head 200 according to a second embodiment of the invention. FIG. 9 is a process cross-sectional view illustrating a method for manufacturing a recording head 200 according to a second embodiment of the invention.

Explanation of symbols

100, 200 recording head

Claims (10)

A recording head that discharges the liquid from the discharge port by applying thermal energy to the liquid,
A first liquid supply channel for supplying the liquid to the discharge port;
A second liquid supply channel for supplying the liquid to the first liquid supply channel; a filter unit disposed between the second liquid supply channel and the first liquid supply channel; A semiconductor substrate comprising:
With
The filter unit is
There are a plurality of through holes arranged so as to remove foreign substances from the liquid supplied by the first liquid supply flow path and allow the liquid from which foreign substances have been removed to pass through the first liquid supply flow path. The recording head is formed of a semiconductor having impurities at a higher concentration than the periphery of the filter portion in the semiconductor substrate. The recording head according to claim 1, wherein the filter portion extends in a lattice shape along the surface of the semiconductor substrate. The recording head according to claim 1, wherein a thickness of the filter portion is 5 μm or less. When the average opening area of each of the plurality of through holes is OA1, the opening area of the discharge port is OA2, and the total opening area of the plurality of through holes is SOA,
OA1 ≦ OA2
And OA2 <SOA
The recording head according to claim 1, wherein: 5. The recording head according to claim 1, wherein the second liquid supply channel has an upper cross-sectional area smaller than a lower cross-sectional area. 6. The semiconductor substrate is made of a semiconductor mainly composed of silicon,
The recording head according to claim 5, wherein a side surface of the second liquid supply channel is a <100> surface or a <110> surface of silicon. The semiconductor substrate is
The electrothermal transducer according to claim 1, further comprising an electrothermal conversion element disposed below the discharge port so that thermal energy is applied to the liquid supplied to the discharge port. The recording head described. The recording head according to claim 7, further comprising a metal film between the discharge port and the electrothermal conversion element. A method of manufacturing a recording head that discharges the liquid from a discharge port by applying thermal energy to the liquid,
A first step of implanting impurities in a mesh-like pattern into a first region on the surface side of the semiconductor substrate that should be below the discharge port;
A second region that continues from a part of the back surface of the semiconductor substrate to the first region is selectively etched using an etchant having an etching selectivity according to the concentration of impurities, thereby providing a second liquid. Forming a supply channel and selectively etching the region of the first region into which the impurities are not implanted with the etchant to form a filter portion having the mesh pattern; And the process of
A third step of forming a first liquid supply channel for supplying the liquid that has passed through the filter unit to the discharge port, above the semiconductor substrate;
A method of manufacturing a recording head, comprising: The method of manufacturing a recording head according to claim 9, wherein in the first step, the impurity is implanted to a depth of 5 μm or less from the surface of the semiconductor substrate.

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