JP2011207072A - Method for manufacturing liquid jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid jet head in which an adhesive reservoir is prevented from forming therein to achieve an improvement in yield.SOLUTION: The method includes: a step of forming a pressure generating element 300 on a first wafer 110; a step of joining the first wafer 110 to a second wafer 130 by means of an adhesive 35 to form a joined body 250; a step of wet-etching the first wafer 110 to form channels for a pressure generating chamber 12, etc.; and a step of dividing the joined body 250 into a plurality of chips in a predetermined size. The method also includes, prior to the step of forming the joined body 250, a step of forming, in the outer periphery of the joining surface of at least either of the first wafer 110 or the second wafer 130, a recessed part for a surplus of the adhesive 35 to be flowed therein.

Description

The present invention relates to a method of manufacturing a liquid ejecting head in which a liquid in a pressure generating chamber is ejected from a nozzle by a pressure generating element.

As a structure of an ink jet recording head which is a typical example of a liquid ejecting head, for example, a flow path forming substrate formed of a silicon substrate in which a pressure generation chamber communicating with a nozzle is formed, and one surface of the flow path forming substrate And a sealing substrate (protective substrate) having a piezoelectric element holding portion that is bonded to the surface of the flow path forming substrate on the piezoelectric element side and seals the piezoelectric element (for example, , See Patent Document 1).

In addition, the ink jet recording head having such a structure is manufactured as follows, for example. First, a piezoelectric element is formed on one side of a silicon wafer on which a plurality of flow path forming substrates are integrally formed via a diaphragm. Then, a sealing substrate forming material to be a sealing substrate is bonded to the silicon wafer with an adhesive, and the silicon wafer is wet-etched with an alkaline solution in a state where the sealing substrate forming material is bonded. Form. Thereafter, the ink jet recording head is manufactured by dividing the silicon wafer into a predetermined chip size.

Further, with the recent miniaturization of the head, a relatively thin silicon substrate has been used as the flow path forming substrate. As a method for manufacturing an ink jet recording head having a relatively thin channel forming substrate, for example, a protective substrate wafer is bonded to a channel forming substrate wafer (silicon wafer) with an adhesive, and then the flow is formed. There is a method of forming a pressure generation chamber or the like by, for example, wet etching after processing the path forming substrate wafer to a predetermined thickness (see, for example, Patent Document 2).

JP 2003-266394 A JP 2004-82722 A

As described above, the flow path forming substrate wafer (first wafer) and the protective substrate wafer (second
Are bonded with an adhesive. Therefore, for example, as shown in FIG. 10, when the bonded body 500 is formed by bonding the first wafer 510 and the second wafer 530 with the adhesive 535, the excess of the adhesive 535 is bonded to the bonded body. A so-called adhesive reservoir 535a is formed in which the adhesive 535 is pushed out to the outside of the outer peripheral edge of the bonded body 500 and accumulated in the adhesive 535.

When the pressure generating chamber is formed by wet etching, the adhesive reservoir is easily dropped by being damaged by the etching solution. If the foreign material from which the adhesive reservoir has fallen adheres to the first or second wafer, there is a risk that the yield will decrease.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method of manufacturing a liquid ejecting head capable of suppressing the formation of an adhesive reservoir and improving the yield.

The present invention for solving the above-described problems includes a first substrate in which a pressure generating chamber communicating with a nozzle for ejecting droplets is formed, and a pressure provided in the pressure generating chamber provided on one surface side of the first substrate. And a second substrate bonded to the one surface side of the first substrate, wherein a plurality of the first substrates are integrally formed. A step of forming the pressure generating element on the first wafer to be formed; and bonding the first wafer to the second wafer on which a plurality of the second substrates are integrally formed with an adhesive. A step of forming a body, a step of forming the pressure generating chamber by wet etching the first wafer, and a step of dividing the joined body into a plurality of chips of a predetermined size. Of the process of forming the joined body And a step of forming a recess into which an excess of the adhesive flows in an outer peripheral portion of a joint surface with at least one of the first and second wafers. Is in the way.
In the present invention, when the first wafer and the second wafer are bonded, an excess of the adhesive for bonding these wafers flows into the recess, so that an adhesive pool is formed on the outer peripheral portion of the bonded body. The formation can be suppressed. For this reason, when the first wafer is subsequently wet-etched to form the pressure generation chamber, the adhesive reservoir can be substantially prevented from falling off. That is, it is possible to substantially prevent the occurrence of manufacturing defects due to the foreign matter from which the adhesive reservoir has fallen adhered to the first or second substrate.

Here, it is preferable to form the concave portion continuously over the entire circumference of the first or second wafer. Further, it is preferable that a plurality of the concave portions are formed in the radial direction of the first or second wafer. In addition, when one of the first wafer and the second wafer has a larger diameter than the other, it is preferable to form the concave portion in an exposed portion of the outer peripheral portion of the bonding surface. Preferably, the recess is formed in each of the first wafer and the second wafer. Thereby, it can further suppress that the excess part of an adhesive flows into a recessed part reliably, and an adhesive pool is formed in the outer peripheral part of a joined body.

Further, when the concave portion is formed in each of the first wafer and the second wafer, it is preferable that the concave portion is formed at a different position between the first wafer and the second wafer. Thereby, the rigidity of the outer peripheral portion of the joined body can be sufficiently ensured while suppressing the formation of the adhesive reservoir in the outer peripheral portion of the joined body.

FIG. 2 is an exploded perspective view illustrating a schematic configuration of a recording head according to an embodiment. 2A and 2B are a plan view and a cross-sectional view of a recording head according to an embodiment. FIG. 5 is a cross-sectional view illustrating an outline of a manufacturing process of a recording head according to an embodiment. FIG. 5 is a cross-sectional view illustrating an outline of a manufacturing process of a recording head according to an embodiment. FIG. 10 is a plan view showing a modification of the manufacturing process of the recording head according to the embodiment. FIG. 10 is a cross-sectional view illustrating a modification of the manufacturing process of the recording head according to the embodiment. FIG. 10 is a plan view showing a modification of the manufacturing process of the recording head according to the embodiment. FIG. 10 is a cross-sectional view illustrating a modification of the manufacturing process of the recording head according to the embodiment. FIG. 10 is a cross-sectional view illustrating a modification of the manufacturing process of the recording head according to the embodiment. It is sectional drawing which shows the manufacturing process of the recording head based on a prior art.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is an exploded perspective view showing a schematic configuration of an ink jet recording head which is an example of a liquid jet head according to an embodiment of the present invention. FIG. 2 is a plan view of FIG. 1 and its AA ′ line. It is sectional drawing.

As shown in the drawing, a flow path forming substrate 10 which is a first substrate made of a silicon substrate has an elastic film 50 made of an oxide film formed on one surface thereof. In the flow path forming substrate 10, a plurality of pressure generating chambers 12 partitioned by a partition wall 11 are arranged in parallel in the width direction. Flow path forming substrate 1
On the one end side in the longitudinal direction of the zero pressure generation chamber 12, each pressure generation chamber 12 is partitioned by a partition wall 11.
An ink supply path 13 and a communication path 14 communicating with each other are provided. Furthermore, a communication portion 15 that communicates with each communication path 14 is provided outside the communication path 14. The communication portion 15 communicates with a reservoir portion 32 of a protective substrate 30 that is a second substrate, which will be described later, and constitutes a reservoir 100 serving as a common ink chamber (liquid chamber) for each pressure generating chamber 12.

On the other surface side of the flow path forming substrate 10, a nozzle plate 20 in which a nozzle 21 communicating with each pressure generating chamber 12 is formed is interposed via an insulating film 51 used as a mask when the pressure generating chamber 12 is formed. Are joined. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, or stainless steel. The insulating film 51 may be removed and the nozzle plate 20 may be directly bonded to the flow path forming substrate 10.

As described above, the elastic film 50 is formed on one surface side of the flow path forming substrate 10, and the insulator film 55 made of a material different from the elastic film 50 is formed on the elastic film 50. . Further, a piezoelectric element 300 as a pressure generating element that generates pressure in the pressure generating chamber 12 is formed on the insulator film 55. In the present embodiment, the piezoelectric element 300 includes the insulator film 5.
5, a lower electrode film 60 that is a common electrode formed on 5, a piezoelectric layer 70 that is formed on the lower electrode film 60, and an upper electrode film 80 that is an individual electrode formed on the piezoelectric layer 70. It is configured.
In addition, each upper electrode film 80 of the piezoelectric element 300 is connected to a lead electrode 90,
Each upper electrode film 80 and a drive IC described later are connected through the lead electrode 90.

On the surface of the flow path forming substrate 10 on the side of the piezoelectric element 300, specifically, on the lower electrode film 60, the elastic film 50, and the lead electrode 90, there is a second having a piezoelectric element holding portion 31 for protecting the piezoelectric element 300. The protective substrate 30 that is the substrate is bonded by, for example, an adhesive 35. A reservoir portion 32 is provided on the protective substrate 30 together with the piezoelectric element holding portion 31. The reservoir section 32 communicates with the communication section 15 formed on the flow path forming substrate 10 as described above to configure the reservoir 100.

The material of the protective substrate 30 is not particularly limited, but it is preferable to use substantially the same material as the thermal expansion coefficient of the flow path forming substrate 10, for example, a glass material, a ceramic material, etc. In this embodiment, the flow path forming substrate is used. A silicon substrate which is the same material as 10 is used.

Further, the protective substrate 30 is provided with a through hole 33 that penetrates the protective substrate 30 in the thickness direction, and the vicinity of the end portion of the lead electrode 90 drawn from each piezoelectric element 300 is exposed in the through hole 33. Has been. A driving IC 200 for driving the piezoelectric elements 300 arranged side by side is fixed on the protective substrate 30. The driving IC 200 and the lead electrode 90 are electrically connected by a connection wiring 210 made of a conductive wire such as a bonding wire extending in the through hole 33.

On the protective substrate 30, a compliance substrate 40 comprising a sealing film 41 and a fixing plate 42.
Are joined. Here, the sealing film 41 is made of a material having low rigidity and flexibility. One surface of the reservoir portion 32 is sealed with the sealing film 41. The fixing plate 42 is formed of a hard material such as metal. A region of the fixing plate 42 facing the reservoir 100 is an opening 43 that is completely removed in the thickness direction, and one surface of the reservoir 100 is sealed only with a flexible sealing film 41. ing.

In such an ink jet recording head of this embodiment, ink is taken in from an external ink supply means (not shown), filled with ink from the reservoir 100 to the nozzle 21, and then generates pressure according to a recording signal from the drive IC 200. By applying a voltage to each piezoelectric element 300 corresponding to the chamber 12 to bend and deform, the pressure in each pressure generating chamber 12 is increased and ink droplets are ejected from the nozzles 21.

Hereinafter, a method for manufacturing such an ink jet recording head will be described with reference to FIGS.
First, as shown in FIG. 3A, an elastic film 50 and an insulating film are formed on one side of a flow path forming substrate wafer (first wafer) 110 on which a plurality of flow path forming substrates 10 are integrally formed. Body membrane 55
Then, the piezoelectric element 300 and the lead electrode 90 are sequentially formed. In addition, since the formation method of these piezoelectric elements 300 grade | etc., Is a well-known technique, detailed description is abbreviate | omitted. A chamfered portion 111 is provided on the outer peripheral edge of the flow path forming substrate wafer 110. By providing the chamfered portion 111, the occurrence of chipping or cracking in the outer peripheral portion of the flow path forming substrate wafer 110 is suppressed.

On the other hand, as shown in FIG. 3B, a protective substrate wafer 130 in which a plurality of protective substrates 30 are integrally formed is provided with a piezoelectric element holding portion 31, a reservoir portion 32, and a through hole corresponding to each protective substrate 30. 33 is formed by etching, for example. Further, a recess 131 is formed in the outer peripheral portion of the joint surface between the protective substrate wafer 130 and the flow path forming substrate wafer. here,
The outer peripheral portion of the protective substrate wafer 130 refers to a portion outside the region to be the protective substrate 30. The recess 131 is for allowing the surplus portion of the adhesive 35 to flow when the flow path forming substrate wafer 110 and the protective substrate wafer 130 are bonded by the adhesive 35 in a process described later. As shown in FIG. 5, the recess 131 is continuously formed along the outer peripheral edge of the protective substrate wafer 130 over the entire circumference of the protective substrate wafer 130. Further, in the present embodiment, as shown in FIG. 3B, a plurality of concave portions 131 (for example, along the radial direction) are formed on the outer peripheral portion of the joint surface of the protective substrate wafer 130 with the flow path forming substrate wafer 110. 3). The plurality of recesses 131 are provided concentrically, for example.

For example, an R-shaped chamfered portion 132 is provided in advance on the outer peripheral edge of the protective substrate wafer 130 in the same manner as the flow path forming substrate wafer 110. As a result, the occurrence of chipping or cracking in the outer peripheral portion of the protective substrate wafer 130 is suppressed. As described above, when the chamfered portion 132 of the protective substrate wafer 130 is provided, the recess 131 is preferably provided in a region inside the chamfered portion 132.

Next, as shown in FIG. 3C, the flow path forming substrate wafer 110 and the protective substrate wafer 1 are formed.
30 is bonded with an adhesive 35 to form a wafer bonded body 250. At this time, the surplus portion of the adhesive 35 pushed toward the outside of the wafer bonded body 250 flows into the recess 131 provided in the outer peripheral portion of the protective substrate wafer 130. For this reason, it can suppress that the excess part of the adhesive agent 35 protrudes outside the outer-periphery edge part of the wafer bonded body 250. FIG. That is, it is possible to substantially prevent a so-called adhesive reservoir from being formed outside the outer peripheral edge of the wafer bonded body 250.

In this embodiment, the recess 131 that is the relief groove of the adhesive 35 is formed in the protective substrate wafer 130 that is the second substrate. Instead of the recess 131, for example, FIG.
As shown in FIG. 4, the recess 112 may be formed in the flow path forming substrate wafer 110 which is the first wafer. In this embodiment, each recess 131 is continuously formed over the entire circumference of the protective substrate wafer 130. For example, as shown in FIG.
31 may be provided intermittently on the outer peripheral portion of the protective substrate wafer 130. Further, as shown in FIG. 7B, the recess 131 may be composed of a plurality of dimple-shaped holes 133. Further, for example, as shown in FIG. 8A, the recess 131 may be formed in the protective substrate wafer 130 and the recess 112 may be formed in the flow path forming substrate wafer 110. In any of these configurations, the surplus of the adhesive 35 is formed in the recesses 131 and 112.
The adhesive pool can be substantially prevented from being formed outside the outer peripheral edge of the wafer bonded body 250.

When the recess 112 is formed in the flow path forming substrate wafer 110 and the recess 131 is formed in the protective substrate wafer 130, as shown in FIG. 8B, the recess of the flow path forming substrate wafer 110 is formed. 112 and the recess 131 of the protective substrate wafer 130 are preferably provided at different positions. That is, it is preferable that the recess 112 and the recess 131 are provided so as not to face each other. As a result, it is possible to substantially prevent the adhesive pool from being formed outside the outer peripheral edge portion of the wafer bonded body 250 as described above, and to ensure sufficient rigidity at the outer peripheral portion of the wafer bonded body 250. can do.

After the flow path forming substrate wafer 110 and the protective substrate wafer 130 are bonded, as shown in FIG. 4A, the surface of the flow path forming substrate wafer 110 to which the protective substrate wafer 130 is bonded By processing the opposite surface, the flow path forming substrate wafer 110 has a predetermined thickness. Specifically, the flow path forming substrate wafer 110 is ground to a certain thickness by a back surface polishing apparatus (back grinder) or the like. Thereafter, for example, the flow path forming substrate wafer 110 is wet-etched using an etchant made of hydrofluoric acid or the like to have a predetermined thickness.

Next, the flow path such as the pressure generation chamber 12 is formed by wet etching the flow path forming substrate wafer 110. Specifically, as shown in FIG. 4B, an insulating film 51 made of, for example, silicon nitride (SiN) is newly formed on the surface of the flow path forming substrate wafer 110, and a resist or the like (not shown) is interposed therebetween. To pattern into a predetermined shape. And this insulating film 5
1 is a mask for forming a flow path forming substrate 110, for example, potassium hydroxide (KOH)
Wet etching is performed using an alkaline solution such as an aqueous solution. As a result, as shown in FIG. 4C, the pressure generation chamber 12, the ink supply path 13, the communication path 14, and the communication portion 15 are formed in the flow path forming substrate wafer 110.

At this time, in the manufacturing method of the present invention, since a so-called adhesive reservoir protruding outside the outer peripheral edge portion of the wafer bonded body 250 is not formed, a part of the adhesive 35 drops off and becomes a foreign matter. It can be substantially prevented. Therefore, it is possible to suppress the foreign matter from which the adhesive 35 has dropped off from adhering to the flow path forming substrate wafer 110 or the protective substrate wafer 130, and to substantially prevent the yield from being reduced due to the attachment of the foreign matter. it can.

Thereafter, as shown in FIG. 4 (d), an unnecessary portion of the outer peripheral edge of the wafer bonded body 250 is removed.
For example, it is removed by cutting by dicing or the like. The nozzle plate 20 having the nozzles 21 is bonded to the surface of the flow path forming substrate wafer 110 opposite to the protective substrate wafer 130, and the compliance substrate 4 is attached to the protective substrate wafer 130.
The ink jet recording head having the above-described structure is manufactured by joining 0 and dividing the flow path forming substrate wafer 110 and the like into one chip size as shown in FIG.

Although one embodiment of the present invention has been described above, of course, the present invention is not limited to such an embodiment.
For example, in the above-described embodiment, the flow path forming substrate wafer 110 and the protective substrate wafer 1
Although the example using the silicon substrate having substantially the same diameter as 30 has been described, the sizes of these wafers may be different. For example, as shown in FIG. 9, a silicon wafer having a larger diameter than the flow path forming substrate wafer 110 may be used as the protective substrate wafer 130A. When such a protective substrate wafer 130 and the flow path forming substrate wafer 110 are bonded together by the adhesive 35, the flow path forming substrate wafer 110 of the protective substrate wafer 130 is used.
In the outer peripheral portion of the joint surface, there is an exposed portion 135 where the joint surface is exposed. In such a case, it is preferable to form the recess 131 in the exposed portion 135 of the protective substrate wafer 130. Thereby, the surplus part of the adhesive 35 is more likely to flow into the recess 131.

In the above-described embodiment, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention is widely applied to all liquid ejecting heads, and ejects liquid other than ink. Of course, it can also be applied. Other liquid ejecting heads include, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, organic EL displays, and FEDs (field emission displays). Examples thereof include an electrode material ejection head used for electrode formation, a bioorganic matter ejection head used for biochip production, and the like.

DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generation chamber, 20 Nozzle plate, 30 Protection board | substrate, 35 Adhesive agent, 40 Compliance board | substrate, 50 Elastic film, 55 Insulator film, 60 Lower electrode film, 70 Piezoelectric layer, 80 Upper electrode film 90 lead electrodes,
100 reservoir, 110 wafer for flow path forming substrate, 111 chamfered portion, 13
0 wafer for protective substrate, 131 recessed portion, 132 chamfered portion, 135 exposed portion,
250 wafer bonded body, 300 piezoelectric element

Claims (6)

A first substrate in which a pressure generating chamber communicating with a nozzle for ejecting liquid droplets is formed; a pressure generating element provided on one side of the first substrate for generating pressure in the pressure generating chamber; A liquid ejecting head manufacturing method comprising: a second substrate bonded to the one surface side of the first substrate;
Forming the pressure generating element on a first wafer on which a plurality of the first substrates are integrally formed;
Forming a bonded body by bonding the first wafer to a second wafer on which a plurality of the second substrates are integrally formed with an adhesive;
Forming the pressure generating chamber by wet etching the first wafer;
Dividing the joined body into a plurality of chips of a predetermined size, and
And before the step of forming the joined body,
A method of manufacturing a liquid jet head, comprising: forming a recess into which an excess of the adhesive flows in an outer peripheral portion of a joint surface with at least one of the first and second wafers. 2. The method of manufacturing a liquid jet head according to claim 1, wherein the recess is formed continuously over the entire circumference of the first or second wafer. The method of manufacturing a liquid jet head according to claim 1, wherein a plurality of the concave portions are formed in a radial direction of the first or second wafer. When one of the first wafer or the second wafer has a larger diameter than the other,
The said recessed part is formed in the exposed part of the outer peripheral part of the said joint surface, The Claim 1 characterized by the above-mentioned.
4. The method for manufacturing a liquid jet head according to claim 3. 5. The method of manufacturing a liquid jet head according to claim 1, wherein the concave portion is formed in each of the first wafer and the second wafer. 6. The method of manufacturing a liquid jet head according to claim 5, wherein the concave portion is formed at a different position between the first wafer and the second wafer.

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