JP2008230141A - Machining method of silicon wafer and manufacturing process of liquid ejection head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining method of a silicon wafer for forming a break pattern efficiently on the periphery of each substrate with high precision, and separating each substrate along the break pattern, and to provide a manufacturing process of a liquid ejection head. <P>SOLUTION: Before or during formation of a through hole 201 by an isotropic etching, at least one hole 210 is bored to penetrate a silicon wafer 130 in the thickness direction by laser beam machining at a portion 205 where first and second (111) faces and a third or fourth (111) face intersect at an acute angle at the end portion of the through hole defined by the first and second (111) faces and the third or fourth (111) face. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for processing a silicon wafer integrally having a plurality of silicon substrates, and a method for manufacturing a liquid jet head that ejects liquid droplets, and more particularly, an inkjet that is manufactured using a silicon wafer and ejects ink droplets as liquid droplets. The present invention relates to a method for manufacturing a recording head.

  Conventionally, for example, a liquid ejecting head that discharges liquid droplets from a nozzle by applying pressure to a liquid in a pressure generating chamber by pressure generating means such as a piezoelectric element has been known. As an example, an ink jet recording head that discharges ink droplets may be used. In this ink jet recording head, pressure generating means such as a piezoelectric element is provided on one side of the flow path forming substrate on which the pressure generating chamber is formed, and a nozzle is formed on the other side of the flow path forming substrate. One in which a provided nozzle plate is joined is known.

  Here, the flow path forming substrate constituting such an ink jet recording head is formed of, for example, a silicon single crystal substrate having a (110) surface. Then, a plurality of the flow path forming substrates are integrally formed on the silicon wafer, and then formed by dividing the silicon wafer.

  As a method for dividing a silicon wafer, for example, a break pattern in which a plurality of through holes are arranged at predetermined intervals on a planned cutting line between each flow path type substrate (silicon substrate) formed on the silicon wafer is formed. There is a method of dividing the silicon wafer along the break pattern (see, for example, Patent Document 1).

JP 2006-175668 A

  When such a break pattern composed of a plurality of through holes is formed, a remaining portion composed of a (111) plane inclined with respect to the surface of the silicon wafer is formed in a part of the through holes. In the invention according to Patent Document 1, the remaining portion is intentionally left. By leaving such a remaining portion, the break pattern can be reinforced. However, in other words, the breakability is lowered, and there is also a possibility that the planned cutting line is not stable due to the presence of the remaining portion. For this reason, it is not always necessary to leave the remaining portion, and depending on various conditions such as the thickness of the silicon wafer, it is necessary to form each through hole without leaving the remaining portion.

  However, as described above, since the surface of the remaining portion is constituted by the (111) plane, it takes a relatively long time to remove the remaining portion by wet etching, resulting in low manufacturing efficiency. There is.

  Such a problem exists not only in the manufacturing method of a liquid jet head such as an ink jet recording head but also in the case where a plurality of silicon substrates are obtained by dividing a silicon wafer.

  The present invention has been made in view of such circumstances, and can form a break pattern around each substrate efficiently and with high accuracy, and each substrate can be satisfactorily separated along the break pattern. Another object is to provide a silicon wafer processing method and a liquid jet head manufacturing method.

In the present invention for solving the above-mentioned problems, a break pattern in which a plurality of through holes are arranged at a predetermined interval is formed on a silicon wafer having a (110) surface by anisotropic etching, and the break pattern is formed along the break pattern. When the silicon wafer is divided into a plurality of silicon substrates, each of the through holes has a first (111) plane perpendicular to the (110) plane and a first (111) plane opposite to the first (111) plane. Two (111) planes, a third (111) plane perpendicular to the (110) plane and intersecting the first (111) plane at a predetermined angle, and the third (111) plane. Before the break pattern is formed so as to be constituted by a fourth (111) plane intersecting the second (111) plane at a predetermined angle and the through hole is formed by anisotropic etching Or during the formation, And an end of the through hole constituted by the second (111) plane and the third or fourth (111) plane, and the first or second (111) plane and the third or third Wherein at least one hole penetrating the silicon wafer in the thickness direction is formed by laser processing in a portion where the angle intersecting with the (111) plane of 4 is an acute angle portion. There is a method for processing a wafer.
In the present invention, each through-hole constituting the break pattern can be efficiently and satisfactorily formed in a relatively short time. Therefore, the breakability of the silicon wafer can be improved and the manufacturing cost can be reduced.

  Here, in the break pattern formed along the first (111) plane, the first (111) plane and the second (111) plane of each through hole are alternately arranged on a straight line. It is preferable to form as described above. Thereby, the breakability of the silicon wafer is further improved and the break accuracy is improved. That is, the silicon wafer can be easily and satisfactorily formed along the planned cutting line.

  Furthermore, the present invention provides a flow path forming substrate in which a pressure generating chamber is formed which communicates with a nozzle and is applied with a pressure for ejecting droplets from the nozzle, and a bonding substrate bonded to the flow path forming substrate. A plurality of the bonding substrates are integrally formed on a bonding substrate wafer made of a silicon wafer having a (110) surface, and then processed by the silicon wafer processing method described above. In the method of manufacturing a liquid jet head, the bonding substrate wafer is divided into a plurality of the bonding substrates. According to the present invention, it is possible to satisfactorily form the liquid jet head and to greatly reduce the manufacturing cost.

Hereinafter, the present invention will be described in detail based on embodiments.
(Embodiment 1)
1 is an exploded perspective view of an ink jet recording head manufactured by a manufacturing method according to Embodiment 1 of the present invention, and FIG. 2 is a plan view and a cross-sectional view of FIG.

  As shown in the figure, the flow path forming substrate 10 is a silicon single crystal substrate having a crystal plane orientation of (110) in this embodiment, and an elastic film 50 made of an oxide film is 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.

  Further, an ink supply path 13 and a communication path 14 that are partitioned by a partition wall 11 and communicate with each pressure generation chamber 12 are provided on one end side in the longitudinal direction of the pressure generation chamber 12 of the flow path forming substrate 10. 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 the protective substrate 30 described later, and constitutes a part of the reservoir 100 that becomes a common ink chamber (liquid chamber) of each pressure generating chamber 12.

  Here, the ink supply path 13 is formed to have a narrower cross-sectional area than the pressure generation chamber 12, and the flow path resistance of the ink flowing into the pressure generation chamber 12 from the communication portion 15 is kept constant. . For example, in this embodiment, the ink supply path 13 has a width smaller than the width of the pressure generation chamber 12 by narrowing the flow path on the pressure generation chamber 12 side between the reservoir 100 and each pressure generation chamber 12 in the width direction. It is formed with. In this embodiment, the ink supply path is formed by narrowing the width of the flow path from one side. However, the ink supply path may be formed by narrowing the width of the flow path from both sides. Further, the ink supply path may be formed by narrowing from the thickness direction instead of narrowing the width of the flow path. Each communication path 14 is formed by extending the partition walls 11 on both sides in the width direction of the pressure generating chamber 12 to the communication part 15 side to partition the space between the ink supply path 13 and the communication part 15.

  A nozzle plate 20 in which a plurality of nozzles 21 are formed is fixed to the opening surface side of the flow path forming substrate 10 by, for example, an adhesive or a heat-welded film, and each nozzle 21 has a pressure generating chamber. The ink supply paths 13 communicate with each other in the vicinity of the end on the opposite side. The nozzle plate 20 is made of, for example, glass ceramics, a silicon single crystal substrate, stainless steel, or the like.

  On the other hand, the elastic film 50 is formed on the surface opposite to the opening surface of the flow path forming substrate 10 as described above. The elastic film 50 is made of an oxide film made of a material different from that of the elastic film 50. An insulator film 55 is formed. Furthermore, a piezoelectric element 300 including a lower electrode film 60, a piezoelectric layer 70, and an upper electrode film 80 is formed on the insulator film 55. Here, the piezoelectric element 300 refers to a portion including the lower electrode film 60, the piezoelectric layer 70, and the upper electrode film 80. In the present embodiment, the lower electrode film 60 is used as a common electrode of the piezoelectric element 300 and the upper electrode film 80 is used as an individual electrode of the piezoelectric element 300. However, there is no problem even if this is reversed for convenience of a drive circuit and wiring. For example, a lead electrode 90 made of, for example, gold (Au) is connected to the upper electrode film 80 of each piezoelectric element 300, and a voltage is selectively applied to each piezoelectric element 300 via the lead electrode 90. It has become so.

  On the flow path forming substrate 10 on which such a piezoelectric element 300 is formed, a protective substrate 30 that is a bonding substrate having a piezoelectric element holding portion 31 for bonding the piezoelectric element 300 is bonded by, for example, an adhesive layer 35. Has been. Note that the space defined by the piezoelectric element holding portion 31 may be sealed or may not be sealed. Further, the protective substrate 30 is provided with a reservoir portion 32 that constitutes at least a part of the reservoir 100 in which the ink supplied to the plurality of pressure generating chambers 12 is stored. In this embodiment, the reservoir portion 32 is formed through the protective substrate 30 in the thickness direction and across the width direction of the pressure generating chamber 12, and the communication portion 15 of the flow path forming substrate 10 as described above. And the reservoir 100 is configured. Note that the communication portion 15 of the flow path forming substrate 10 may be divided into a plurality for each pressure generation chamber 12 and only the reservoir portion 32 may be used as the reservoir. Further, for example, only the pressure generation chamber 12 is provided in the flow path forming substrate 10, and a reservoir and a member interposed between the flow path forming substrate 10 and the protective substrate 30 (for example, the elastic film 50, the insulator film 55, etc.) An ink supply path 13 that communicates with each pressure generation chamber 12 may be provided. Further, the protective substrate 30 is provided with an exposure hole 33 penetrating 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 exposure hole 33. Yes.

  As such a protective substrate 30, a silicon single crystal substrate, which is the same material as the flow path forming substrate 10, is used.

  Further, a compliance substrate 40 including a sealing film 41 and a fixing plate 42 is bonded onto the protective substrate 30. Here, the sealing film 41 is made of an organic material having low rigidity and flexibility, and one surface of the reservoir portion 32 is sealed by the sealing film 41. The fixing plate 42 is made 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 ink introduction port connected to an external ink supply means (not shown), and the interior from the reservoir 100 to the nozzle 21 is filled with ink. In accordance with a recording signal from (not shown), a voltage is applied between each of the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 to bend and deform the piezoelectric element 300, whereby each pressure generation chamber 12. The internal pressure increases and ink droplets are ejected from the nozzle 21.

  Here, for example, the flow path forming substrate 10, the protective substrate 30, and the like constituting the ink jet recording head according to this embodiment are formed from a silicon single crystal substrate having a (110) surface as described above. Become. For example, as shown in FIG. 3, a plurality of protective substrates 30 are integrally formed on a protective substrate wafer 130 which is a silicon wafer of about 6 inches, that is, the protective substrate wafer 130 is anisotropically etched. By forming a plurality of piezoelectric element holding portions 31, reservoir portions 32, etc., the protective substrate wafer 130 is divided along the first and second scheduled cutting lines 150A and 150B indicated by the one-dot chain line in the figure. Is formed.

  The first planned cutting line 150A is arranged along the first (111) plane perpendicular to the (110) plane, and the second planned cutting line 150B is the axial direction of the first (111) plane. It is arranged along. In this embodiment, since the orientation flat (oriental flat) of the protective substrate wafer 130 is formed along the first (111) plane, the first planned cutting line 150A is in the direction along the orientation flat. The second planned cutting line 150B is in a direction perpendicular to the orientation flat.

  A break pattern in which a plurality of through holes are arranged at a predetermined interval is formed on the first and second planned cutting lines 150A and 150B. For example, in the present embodiment, as shown in FIG. 4, a break pattern 200A having a plurality of through holes 201A having a substantially rectangular opening shape is formed on the first planned cutting line 150A. On the other hand, on the second planned cutting line 150B, as shown in FIG. 5, from an orthogonal part 201a extending in a direction orthogonal to the second planned cutting line 150B, from both ends of the orthogonal part 201a, A break pattern 200B composed of a plurality of through-holes 201B formed of an extending portion 201b extending to the second planned cutting line 150B in a direction inclined at a predetermined angle with the orthogonal portion 201a is formed. And between these each through-hole 201 (201A, 201B) becomes the weak part 202, when an external force is applied to the protective substrate wafer 130, the weak part 202 is cracked, and the break pattern 200 (scheduled cutting line) 150), the protective substrate wafer 130 is divided. That is, the protective substrate wafer 130 is separated into the protective substrates 30.

  The through-holes 201A and 201B constituting the break patterns 200A and 200B according to the present embodiment have different opening shapes, but both are first to be perpendicular to the surface ((110) plane) of the protective substrate wafer 130. The (111) plane 130a, the second (111) plane 130b opposite to the first (111) plane 130a, and a predetermined angle with the first (111) plane 130a perpendicular to the (110) plane A third (111) surface 130c that intersects with the third (111) surface 130c and a fourth (111) surface 130d that faces the second (111) surface 130b at a predetermined angle. It consists of

  The arrangement of the through holes 201 of each break pattern 200 may be determined as appropriate, but each of the through holes 201 of the break pattern 200A provided on the first planned cutting line 150A is the number of each through hole 201. It is preferable that the first (111) surface 130a and the second (111) surface 130b are alternately arranged on a straight line, that is, on the first planned cutting line 150A (see FIG. 4). ). Thereby, the protective substrate wafer 130 can be accurately divided along the break pattern 200 (scheduled cutting line 150).

  Each of the through holes 201 constituting the break pattern 200 is formed at the same time when the reservoir portion 32 and the like are formed on the protective substrate wafer 130 by wet etching, as will be described below. FIG. 6 is a cross-sectional view of the protective substrate wafer 130 in the longitudinal direction of the pressure generating chamber.

  First, as shown in FIG. 6A, a protective substrate wafer 130 which is a silicon wafer having a plane orientation (110) is thermally oxidized to form a protective film 131 made of silicon dioxide on the surface thereof. Next, as shown in FIG. 6B, the protective film 131 is patterned into a predetermined shape by etching through a resist film or the like. That is, the opening 132 is formed in the protective film 131 where the piezoelectric element holding portion 31, the reservoir portion 32, the exposure hole 33, and the through holes 201 of the break pattern 200 are formed.

  Next, anisotropic wet etching is started on both sides of the protective substrate wafer 130 using the protective film 131 as a mask. Here, in each through-hole 201, etching proceeds in the depth direction while the first to fourth (111) surfaces 130a to 130d perpendicular to the (110) surface of the surface of the protective substrate wafer 130 are exposed ( (See FIGS. 4 and 5).

  At that time, the end portion of the through-hole 201 constituted by the first and second (111) surfaces 130a and 130b and the third or fourth (111) surfaces 130c and 130d and the first (111) surface. In the acute angle portion 205 in which the intersection angle between the surface 130a or the second (111) surface 130b and the third (111) surface 130c or the fourth (111) surface 130d is an acute angle (see FIGS. 4 and 5). As shown in FIG. 7A, the thickness of the protective substrate wafer 130 is the fifth and sixth (111) surfaces that form an angle of about 35 ° with the surface ((110) surface) of the protective substrate wafer 130. Etching proceeds while being exposed in the direction. For this reason, when the opening diameter of the through hole 201 is small, simply by anisotropically etching the protective substrate wafer 130, each acute angle portion 205 is placed in the through hole 201 as shown in FIG. A remaining portion 280 protruding in a bowl shape is formed.

  In contrast, in the present embodiment, a region where the remaining portion 280 is formed during the formation of the through hole 201 in the protective substrate wafer 130, that is, during the anisotropic etching of the protective substrate wafer 130, That is, as shown in FIGS. 8 and 9, a hole 210 that penetrates the protective substrate wafer 130 in the thickness direction is formed in a portion that becomes the acute angle portion 205 of the protective substrate wafer 130. The size of the hole 210 is not particularly limited as long as the hole is large enough to allow the etching solution to flow into the hole 210. Moreover, the number is not specifically limited, At least 1 should just be provided.

  Then, after the hole 210 is formed in the protective substrate wafer 130 in this way, the protective substrate wafer 130 is again anisotropically etched. Thereby, as shown in FIG. 6C, the piezoelectric element holding portion 31, the reservoir portion 32, and the exposure hole 33 are formed in the protective substrate wafer 130. At the same time, the through holes 201 constituting the break pattern 200 are formed.

  Thus, the etching time can be shortened by forming the hole by laser processing while the through hole is formed by etching the protective substrate wafer. Therefore, each through hole can be formed with high accuracy. In addition, the piezoelectric element holding portion 31 and the like that are simultaneously formed can be formed with high accuracy.

  As described above, the etching of the protective substrate wafer 130 proceeds in the depth (thickness) direction while the remaining portion 280 is formed in the portion corresponding to the acute angle portion 205, but in the portion where the hole portion 210 is formed ( Since the surface other than the (111) surface is exposed, the etching also proceeds in the planar direction of the wafer. Therefore, the through-hole 201 having no remaining portion 280 in the acute angle portion 205 can be satisfactorily formed in a relatively short time.

  Of course, although the etching rate of the (111) plane is slow, it is not not etched at all. Therefore, the remaining portion can be completely removed by etching. However, it is necessary to etch the protective substrate wafer for a considerably long time, which not only greatly reduces the manufacturing efficiency, but also makes the shape of other parts such as the reservoir 32 unstable and causes ink ejection. There is also a possibility of adversely affecting the characteristics.

  Such a protective substrate wafer 130 is then divided along a break pattern. That is, the protective substrate wafer 130 is separated into the protective substrates 30. Actually, a plurality of flow path forming substrates are bonded to a flow path forming substrate wafer formed integrally, and then divided together with the flow path forming substrate wafer. Specifically, as shown in FIG. 10A, such a protective substrate wafer 130 is formed on a flow path forming substrate wafer 110 on which a piezoelectric element 300 is formed by film formation and photolithography, for example. Bonding is performed through an adhesive layer 35 made of an epoxy adhesive or the like. Next, as shown in FIG. 10B, after the flow path forming substrate wafer 110 is thinned to a certain thickness, as shown in FIG. 11A, on the flow path forming substrate wafer 110, for example, An insulating film 52 is newly formed and patterned into a predetermined shape. Then, as shown in FIG. 11B, the flow path forming substrate wafer 110 is anisotropically etched (wet etching) using the insulating film 52 as a mask, and the pressure generating chamber 12 is applied to the flow path forming substrate wafer 110. The ink supply path 13, the communication path 14, and the communication part 15 are formed. Further, the elastic film 50 and the insulator film 55 are removed, and the communication part 15 and the reservoir part 32 are communicated.

  Thereafter, 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 40 is bonded to the protective substrate wafer 130. To do. Then, along with the flow path forming substrate wafer 110, the protective substrate wafer 130 is divided along the break pattern 200. That is, the substrate is divided into one chip size flow path forming substrate 10 as shown in FIG. Thereby, an ink jet recording head having the above-described structure is manufactured.

(Other embodiments)
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. For example, in the above-described embodiments, the present invention has been described by exemplifying the break pattern formed on the protective substrate wafer. Of course, it can be applied.

  In the above-described embodiment, the hole is formed in the middle of forming the through hole in the protective substrate wafer 130 by etching. Of course, before the etching of the protective substrate wafer 130 is started. A hole may be formed. Even in this case, of course, the through hole having a predetermined shape can be formed satisfactorily and efficiently.

  In the above-described embodiments, the ink jet recording head has been described as an example of the liquid ejecting head. However, the present invention broadly applies to all liquid ejecting heads and ejects liquids other than ink. Of course, the present invention can also be applied to a method of manufacturing a liquid jet head. 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.

  Further, even when the silicon wafer is divided into a plurality of silicon substrates, the present invention can of course be employed even when the liquid jet head is not manufactured as described above.

FIG. 3 is an exploded perspective view illustrating an example of a recording head. 2A and 2B are a plan view and a cross-sectional view illustrating an example of a recording head. It is a top view explaining the wafer for protective substrates. FIG. 3 is a schematic plan view for explaining a break pattern according to the first embodiment. FIG. 3 is a schematic plan view for explaining a break pattern according to the first embodiment. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head of Embodiment 1. It is a figure explaining a remaining part and is AA 'sectional drawing of FIG. FIG. 4 is a schematic plan view illustrating a manufacturing process of the recording head of Embodiment 1. FIG. 9 is a cross-sectional view taken along the line BB ′ of FIG. 8 illustrating the manufacturing process of the recording head of Embodiment 1. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head of Embodiment 1. FIG. 6 is a cross-sectional view illustrating a manufacturing process of the recording head of Embodiment 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Flow path formation board | substrate, 12 Pressure generating chamber, 20 Nozzle plate, 21 Nozzle, 30 Protection board | substrate, 31 Piezoelectric element holding | maintenance part, 32 Reservoir part, 33 Exposed hole, 40 Compliance board | substrate, 50 Elastic film, 55 Insulator film | membrane, 60 Lower electrode film, 70 Piezoelectric layer, 80 Upper electrode film, 90 Lead electrode, 100 Reservoir, 110 Flow path forming substrate wafer, 130 Protective substrate wafer, 200 Break pattern, 201 Through hole, 202 Vulnerable portion, 205 Acute angle portion 210 holes 300 piezoelectric elements

Claims (3)

A break pattern in which a plurality of through holes are arranged at predetermined intervals on a silicon wafer having a (110) surface is formed by anisotropic etching, and the silicon wafer is divided along the break pattern to form a plurality of When using a silicon substrate,
Each of the through holes is perpendicular to the (110) plane, a first (111) plane perpendicular to the (110) plane, a second (111) plane opposite to the first (111) plane, and The third (111) plane that intersects the first (111) plane at a predetermined angle and the third (111) plane are opposed to each other and intersect the second (111) plane at a predetermined angle. Forming the break pattern to be composed of a fourth (111) plane;
And before or during the formation of the through hole by anisotropic etching, the through hole constituted by the first and second (111) planes and the third or fourth (111) plane. The silicon wafer is formed by laser processing on an end portion and an acute angle portion where an angle between the first or second (111) surface and the third or fourth (111) surface is an acute angle. A method of processing a silicon wafer, comprising forming at least one hole penetrating in the thickness direction.   In the break pattern formed along the first (111) plane, the first (111) plane and the second (111) plane of each through hole are alternately arranged in a straight line. The method for processing a silicon wafer according to claim 1, wherein the silicon wafer is formed as follows. A liquid ejecting head having a flow path forming substrate that is in communication with a nozzle and has a pressure generating chamber to which a pressure for ejecting droplets from the nozzle is formed, and a bonding substrate that is bonded to the flow path forming substrate A manufacturing method of
A plurality of bonded substrates are integrally formed on a bonded substrate wafer made of a silicon wafer having a (110) surface, and the bonded wafer is divided by the silicon wafer processing method according to claim 1 or 2. A manufacturing method of a liquid ejecting head, wherein a plurality of the bonding substrates are used.