JP4196010B2 - Method for bonding glass substrate and semiconductor substrate and method for manufacturing micro relay - Google Patents

Description

  The present invention relates to a bonding method for bonding a glass substrate and a semiconductor substrate, and a method for manufacturing a micro relay using the bonding method.

  In recent years, various micromachines formed by processing a semiconductor substrate by a semiconductor microfabrication process have been provided, and one example is a microrelay (see, for example, Patent Document 1).

  The micro relay described in Patent Document 1 processes a body 1 formed by processing a glass substrate as shown in FIG. 8, an electromagnet device 2, and a semiconductor substrate such as a silicon substrate by a semiconductor fine processing process. The armature block 3 formed by (1) and the cover 4 formed by processing a glass substrate are provided. A storage hole 16 that penetrates in the thickness direction and stores the electromagnet device 2 penetrates in the center of the body 1, and is stored by bonding a lid body 17 made of a silicon thin film (semiconductor substrate) to one surface side of the body 1. The hole 16 is closed, and the electromagnet device 2 is stored in a space surrounded by the inner peripheral surface of the storage hole 16 and the lid body 17.

On the other hand, the armature block 3 includes a frame portion 31 having a rectangular frame shape and an armature 30 supported by the frame portion 31 through a plurality of support spring portions 32 so as to be swingable. The armature block 3 is sandwiched from both sides. A micro relay is configured by joining the frame portion 31 to the body 1 and the cover 4. Here, the lid body 17 and the body 1, the body 1, the cover 4, and the frame portion 31 are joined by anodic bonding. Anodic bonding is generally used as a method for tightly bonding a glass containing mobile ions and a silicon substrate. The laminated substrate is heated to soften the glass side and at the same time use the silicon side as the anode to increase the height between the two. In this method, an electric double layer is generated by applying a voltage, and the substrates are joined together by electrostatic attraction. In the microrelay described in Patent Document 1, after the silicon thin film is anodically bonded to the entire surface of the body 1, the lid 17 and the body 1 are removed by the process of removing the silicon thin film while leaving the lid 17. Be joined.
JP-A-2005-50768

  By the way, since anodic bonding is one in which movable ions (for example, sodium ions) contained in glass move to the surface to generate an electric double layer and bond the glass and the silicon substrate. If the silicon thin film (semiconductor substrate) is also bonded to the portion where the frame portion 31 is bonded at the time of the first bonding (when the lid 17 is bonded) as in the conventional example, the frame portion 31 is Even if the silicon thin film at the part to be joined is removed, the movable ions contributing to the joining at the part are reduced, and the body 1 and the frame part 31 are joined at the second joining (when the frame part 31 is joined). There was a problem that the strength decreased.

  The present invention has been made in view of the above circumstances, and its purpose is to prevent a decrease in bonding strength in the second and subsequent bondings even when the semiconductor substrate is bonded to the same surface of the glass substrate in a plurality of times. An object of the present invention is to provide a method for bonding a glass substrate and a semiconductor substrate and a method for manufacturing a microrelay.

In order to achieve the above object, the invention according to claim 1 is a bonding method in which a semiconductor substrate is anodically bonded to one surface side of a flat glass substrate in a plurality of times, the first semiconductor substrate being a glass substrate. Before bonding, the thickness of a portion of the first semiconductor substrate other than the portion to be bonded to the glass substrate is etched by etching the surface of the first semiconductor substrate facing the one surface of the glass substrate. the thinned with a gap between the one surface of the glass substrate, the first semiconductor substrate by anodic bonding while avoiding a site at which the anodically bonded to another semiconductor substrate after the one surface of the glass substrate by the gap The first semiconductor substrate is formed into a desired shape by etching at least a region corresponding to the gap after the anodic bonding .

The invention of claim 2 is characterized in that, in the invention of claim 1, the etching of the semiconductor substrate is dry etching .

In order to achieve the above object, the invention of claim 3 is provided with an electromagnet device that generates a magnetic attractive force in response to an exciting current to the coil, and a storage portion that is made of a glass substrate and houses the electromagnet device, and in the thickness direction. A body provided with a fixed contact on one surface side, a frame-shaped frame portion made of a semiconductor substrate and fixed to the one surface side of the body, and disposed on the inner side of the frame portion so as to be swingable with respect to the frame portion Armature block supported by the armature block, the armature block having a movable contact that contacts and separates from the fixed contact when the armature swings by the magnetic attraction force of the electromagnet device, and the peripheral portion on the opposite side of the body of the armature block made of a glass substrate A cover that is fixed to the frame portion, and a housing hole that penetrates in the thickness direction is provided in the body. A storage part for storing the electromagnet device is provided by closing the storage hole from the surface side, the frame part is anodically bonded to the one surface side of the body, and the cover is an anode on the side opposite to the body in the frame part. A method of manufacturing a microrelay to be bonded , wherein a surface of one surface of a semiconductor substrate opposite to the one surface of the body is etched before a semiconductor substrate serving as a base of a lid is bonded to the body. Accordingly, the thickness of the portion other than the portion serving as the lid of the semiconductor substrate is reduced to leave a gap with the one surface of the body, and the frame portion is anodically bonded later on the one surface side of the body by the gap. the semiconductor substrate by anodic bonding while avoiding the site, the semiconductor substrate by etching the region corresponding to at least the gap after the anodic bonding And forming the shape of the body.

The invention of claim 4 is characterized in that, in the invention of claim 3, the etching of the semiconductor substrate which is the basis of the lid is dry etching .

  According to the first aspect of the present invention, since the semiconductor substrate is anodically bonded on the one surface side of the glass substrate while avoiding the portion where the semiconductor substrate is anodically bonded later, the semiconductor substrate is bonded to the same surface of the glass substrate in multiple times. Even in this case, it is possible to provide a method for bonding a glass substrate and a semiconductor substrate that can prevent a decrease in bonding strength in the second and subsequent bonding.

  According to the second aspect of the present invention, it is less likely to be affected by the crystal orientation of the semiconductor substrate when forming the gap as compared to other etching.

  According to the invention of claim 3, since the semiconductor substrate which is the basis of the lid body is anodically bonded on the one surface side of the body while avoiding a portion where the frame portion is anodically bonded later, the frame is formed after the lid body is bonded to the body. It is possible to provide a method for manufacturing a microrelay that can prevent a decrease in bonding strength between the frame portion and the body when the portions are bonded.

  According to the invention of claim 4, compared to other etching, it is less likely to be affected by the crystal orientation of the semiconductor substrate when forming a gap in the semiconductor substrate serving as the base of the lid.

  Hereinafter, an embodiment in which the present invention is applied to a microrelay described in the prior art will be described in detail with reference to FIGS.

  The microrelay of this embodiment includes an armature 30 formed by processing a silicon substrate by a micromachining technique, a movable contact 39 that can be displaced by the armature 30, and a fixed contact 14 that contacts and separates from the movable contact 39. 4 and the armature block 3 are housed in a sealed space, and the armature 30 is driven by the electromagnetic force of the electromagnet device 2. The body 1 is made of a rectangular plate-like glass substrate, and a pair of fixed contacts 14 are provided at both ends in the longitudinal direction on one surface side in the thickness direction. The armature block 3 includes a frame-shaped (rectangular frame-shaped) frame portion 31 that is fixed to the one surface side of the body 1 and a frame portion that is disposed inside the frame portion 31 via four support spring portions 32. The armature 30 is swingably supported by the armature 31 and driven by the electromagnetic force generated by the electromagnet device 2, and the armature 30 is supported by two contact pressure spring portions 35, and the movable contact 39 is provided. And two movable contact bases 34. The cover 4 is made of a rectangular plate-shaped glass substrate, and the peripheral portion is fixed to the frame portion 31 on the side opposite to the body 1 in the armature block 3.

  The electromagnet device 2 generates a magnetic flux in accordance with an exciting current applied to the coils 22 and 22 wound around the yoke 20. The yoke 20 extends in the direction of approaching the armature 30 from both ends of the coil winding portion 20a in the longitudinal direction of the elongated rectangular plate and the coil winding portion 20a in which the two coils 22 and 22 are directly wound. The length of the coil winding portion 20a between the pair of leg pieces 20b, 20b and the leg pieces 20b, 20b of the yoke 20 whose opposite end surfaces are excited with different polarities according to the excitation current to the coils 22, 22 is determined. A rectangular plate-shaped permanent magnet 21 arranged in the center of the direction, and an elongated rectangular plate-shaped coil winding on the opposite side of the coil winding portion 20a of the yoke 20 from the surface facing the permanent magnet 21. And a printed circuit board 23 fixed to the coil winding part 20a so as to be orthogonal to the turning part 20a. The yoke 20 is formed by bending or casting an iron plate such as electromagnetic soft iron, and the cross sections of both leg pieces 20b and 20b are formed in a rectangular shape.

  The permanent magnet 21 is magnetized so that the magnetic pole surfaces of both surfaces in the overlapping direction (thickness direction) with the coil winding portion 20 a are different from each other, and one magnetic pole surface abuts on the coil winding portion 20 a of the yoke 20. The thickness dimension is set so that the other magnetic pole surface is located on the same plane as the tip surfaces of the leg pieces 20b, 20b of the yoke 20.

  Further, the movement of the coils 22 and 22 in the major axis direction (that is, the longitudinal direction of the coil winding portion 20a) is restricted by the permanent magnet 21 and the leg pieces 20b and 20b of the yoke 20, respectively. In the printed circuit board 23, conductive patterns 23b are formed at both ends in the longitudinal direction on one surface of the insulating substrate 23a, and the circularly formed portions of the conductive patterns 23b constitute external connection electrodes, and are rectangular. The site | part formed in comprises the coil connection part. Here, the terminals of the coils 22 and 22 are connected to the coil connecting portion, but the coils 22 and 22 are connected when a power source is connected between the external connection electrodes and an excitation current is passed through the coils 22 and 22. The leg surfaces 20b, 20b of the yoke 20 are connected so that the tip surfaces of the leg pieces 20b are different from each other. A bump 24 made of a conductive material (for example, Au, Ag, Cu, solder, etc.) is appropriately fixed to the external connection electrode in each conductive pattern 23b. Instead of fixing the bump 24, a bonding wire is used. May be bonded.

  The body 1 is made of heat-resistant glass, the outer peripheral shape is rectangular, and a storage hole 16 that penetrates in the thickness direction and stores the electromagnet device 2 penetrates in the center, and the vicinity of each of the four corners and the longitudinal direction A through hole 10 penetrating in the thickness direction is provided near the center of both end portions. Further, lands 12 are formed on both sides in the thickness direction of the body 1 and on the periphery of each through hole 10. Here, the lands 12 that overlap in the thickness direction of the body 1 are plated with a conductive material (for example, Cu, Cr, Ti, Pt, Co, Ni, Au, or an alloy thereof) on the inner peripheral surface of the through hole 10. It is electrically connected by the plating layer 10a formed. Further, bumps 13 are appropriately fixed to the lands 12 on the other surface side in the thickness direction of the body 1. By fixing the bumps 13 to the lands 12, the through holes 10 are opened on the other surface side of the body 1. The surface is covered with bumps 13. The opening surface of the through hole 10 is circular, and a conductive pattern 18 that closes the opening surface of the through hole 10 is provided on the one surface of the body 1.

  Further, each of the pair of fixed contacts 14 described above is arranged in parallel in the short direction between two through-holes 10 that are spaced apart in the short direction of the body 1 at both ends in the longitudinal direction of the body 1. It is electrically connected to the lands 12 formed at the periphery of the through-holes 10 at both ends in the short-side direction via conductive patterns 18. Further, in the vicinity of the fixed contact 14 at both ends in the longitudinal direction of the body 1, the grounding is connected to a land 12 having a narrow shape along the short direction and formed at the periphery of the central through hole 10. A conductive pattern 18 'is provided, and the central through hole 10 is also closed by the grounding conductive pattern 18'. Here, in this embodiment, the fixed contact 14 and the conductive pattern 18 are integrally formed by partially plating one surface side of the body with a conductive material. In addition, as a material of the fixed contact 14, the conductive patterns 18, 18 ', and the land 12, for example, a conductive material such as Cr, Ti, Pt, Co, Cu, Ni, Au, or an alloy thereof may be employed. As the material of the bump 13, for example, a conductive material such as Au, Ag, Cu, or solder may be employed. The through hole 10 and the storage hole 16 described above may be formed by, for example, a sand blast method or an etching method. Moreover, you may form the thin film used as a conductive layer by the vapor deposition method, the sputtering method, etc. instead of the plating layer 10a.

  The opening surface of the storage hole 16 has a cross shape, and a lid 17 made of a silicon thin film that closes the storage hole 16 is joined to the one surface side of the body 1. That is, the electromagnet device 2 is inserted into the storage hole 16 such that the front end surfaces of both leg pieces 20 b and 20 c of the yoke 20 face the lid body 17. In the present embodiment, the space surrounded by the inner peripheral surface of the storage hole 16 and the lid body 17 constitutes a storage unit that stores the electromagnet device 2, and the electromagnet device 2 includes the permanent magnet 21 of the body 1. Provided in the magnetic path formed by the armature 30 and the yoke 20 within the thickness dimension, the surface of the insulating substrate 23a in the printed circuit board 23 is substantially flush with the other surface of the body 1.

  The armature block 3 is formed by processing a semiconductor substrate made of a silicon substrate by a semiconductor micromachining process so that the rectangular frame-shaped frame portion 31, the four support spring portions 32, and the frame portion 31 are placed inside the frame portion 31. A rectangular plate-shaped movable base 30a that is disposed and constitutes a part of the armature 30, the above-mentioned four contact pressure springs 35, and the above-mentioned two movable contact bases 34 are formed, and are movable. The armature 30 is composed of a base plate portion 30a and a rectangular plate-shaped magnetic body portion 30b made of a magnetic material (for example, soft iron, electromagnetic stainless steel, permalloy, etc.) fixed to the surface of the movable base portion 30a facing the body 1. It is composed. Accordingly, the armature 30 is swingably supported by the frame portion 31 via the four support spring portions 32. The movable base portion 30a is thinner than the frame portion 31, and the thickness of the armature 30 is between the magnetic body portion 30b of the armature 30 and the lid body 17 in a state where the armature block 3 and the body 1 are joined. Is set to form a predetermined gap.

  The above-described support spring portions 32 are formed at two locations on both sides in the short direction of the movable base portion 30a so as to be separated from each other in the longitudinal direction of the movable base portion 30a. Each support spring portion 32 has one end portion connected to the frame portion 31 continuously and integrally, and the other end portion connected to the movable base portion 30a continuously and integrally. In addition, each support spring part 32 is lengthened by forming the site | part between the said one end part and the said other end part in the planar shape in the meandering shape in the same surface, and the armature 30 is made into the shape. It is possible to disperse the stress applied to each support spring portion 32 when swinging, and to prevent each support spring portion 32 from being damaged.

  In addition, the movable base portion 30a has a rectangular protruding piece 36 extending continuously and integrally from the center of both side edges in the lateral direction, and also from a portion corresponding to the protruding piece 36 on the inner peripheral surface of the frame portion 31. A rectangular projecting piece 37 is continuously extended. In other words, the projecting piece 36 extending from the movable base portion 30a and the projecting piece 37 extending from the frame portion 31 are opposed to each other at their front end surfaces. Here, a convex portion 36a is formed on the tip surface of each protruding piece 36 extending from the movable base portion 30a, and the protruding surface of each protruding piece 37 extended from the frame portion 31 is convex. A recess 37a into which the portion 36a enters is formed. Therefore, the movement of the armature 30 in the plane orthogonal to the thickness direction of the frame portion 31 is restricted by the convex portion 36a contacting the inner peripheral surface of the concave portion 37a. The two support spring portions 32 disposed on the same side edge side of the armature 30 are located on both sides of the projecting piece 36.

  Further, fulcrum protrusions 40 are respectively provided on the surfaces of the protrusions 36 facing the body 1, and by providing the pair of fulcrum protrusions 40, the swinging motion of the armature 30 can be further stabilized. A protective film 41 made of a metal thin film is formed at the tip of the fulcrum protrusion 40 that contacts the body 1 in order to reduce wear, cracks, or chipping.

  The armature block 3 has movable contact base portions 34 disposed between both end portions of the armature 30 and the frame portion 31 in the longitudinal direction of the armature 30, and the armature block 3 and the body 1 in each movable contact base portion 34. A movable contact 39 made of a conductive material is fixed to the opposite surface. Here, the movable contact base portion 34 is supported by the movable base portion 30a via the two contact pressure spring portions 35 described above. The movable base portion 30a is formed in a rectangular plate shape as described above, and the stopper portions 33 that limit the displacement amount of the magnetic body portion 30b are continuously extended from the four corners, and the contact pressure spring. The planar shape of the portion 35 is formed in a U shape along three sides of the outer peripheral edge of the stopper portion 33. The stopper portion 33 limits the amount of displacement of the magnetic body portion 30 b by contacting the one surface of the body 1. As can be seen from the above description, the armature block 3 includes the frame portion 31, the movable base portion 30a, the support spring portion 32, the movable contact holding portion 34, and the contact pressure spring portion 35, which are part of the semiconductor substrate described above. It is configured.

  The cover 4 is made of heat-resistant glass, and a recess (not shown) that secures a swinging space for the armature 30 is formed on the surface facing the armature block 3.

  Next, a method for manufacturing the micro relay of this embodiment will be briefly described.

  In manufacturing the microrelay of this embodiment, a silicon substrate as a semiconductor substrate is processed by a semiconductor micromachining process (micromachining technology) such as a lithography technique and an etching technique to form a frame portion 31, a support spring portion 32, and a contact pressure spring portion. 35, after forming the movable contact base 34 and the movable base 30a constituting a part of the armature 30, the magnetic base 30b made of a magnetic material is fixed to one surface of the movable base 30a on the body 1 side. In addition, the armature block 3 is formed by fixing the movable contact 39 to the movable contact base 34, and the armature block 3 formed in the armature block forming process, the body 1 and the cover 4 are anodic bonded. The frame part 3 of the body 1, the cover 4, and the armature block 3 I have enclosed a sealing step of sealing the space are, and an electromagnet device disposing step after the sealing step accommodates the electromagnetic actuator 2 in the housing portion of the body 1 by fixing the body 1 in a.

  Here, in forming the body 1, the storage hole 16 penetrating in the thickness direction is formed in a portion corresponding to the storage portion in the glass substrate to be the body 1, and the thickness is in the vicinity of the four corners of the glass substrate and in the center of both ends in the longitudinal direction. After forming the through hole 10 penetrating in the direction, a thin film (for example, a silicon thin film) covering the accommodation hole 16 is anodically bonded to the surface of the glass substrate on the side where the fixed contact 14 is provided, and the thin film is patterned. After forming the lid 17 that closes the opening surface of the storage hole 16, the conductive material is partially plated on the one surface side of the body 1, whereby the land 12, the fixed contact 14, the conductive patterns 18, 18 ′, plating The layer 10a is integrally formed. In forming the cover 4, a bonding metal thin film may be formed after forming a recess in the glass substrate to be the cover 4 by an etching method or a sand blast method.

  Here, the joining method of the body 1, the lid body 17, and the frame part 31, which is the gist of the present invention, will be described in more detail.

First, as shown in FIG. 1A, after forming an etching mask 101 having a shape and size that is slightly larger than the lid 17 on one surface of a silicon substrate (first semiconductor substrate) 100, dry etching is performed. The protrusion 102 is formed at the center on the one surface side of the silicon substrate 100 by reducing the thickness of the portion excluding the mask 101 (so-called “sitting down”). Then, the body 1 and the silicon substrate 100 are anodically bonded in a state in which the housing hole 16 opened to one surface side of the body 1 is closed at the front end surface (upper surface in FIG. 1A) of the protrusion 102 (FIG. 1). (See (b) and FIG. 7). Then, after polishing the silicon substrate 100 (see FIG. 1C), an etching mask 101 matching the shape of the lid 17 is formed on one surface of the silicon substrate 100 (see FIG. 1D), and dry etching is performed. The lid 17 is formed by removing the portion of the silicon substrate 100 excluding the etching mask 101 (see FIG. 1E). Thereafter, the frame portion 31 of the armature block 3 is anodically bonded to one surface side of the body 1 (see FIG. 1 (f)).

  That is, in the above-described bonding method, before bonding the silicon substrate 100 that is the basis of the lid body 17 to the body 1, one surface of the silicon substrate 100 that faces the one surface of the body 1 is dry-etched. By sitting down, a gap d (see FIG. 1B) is provided between a portion of the silicon substrate 100 other than the portion to be the lid 17 and one surface of the body 1, so that one surface of the body 1 When the frame part 31 is joined to the body 1 after joining the lid 17 to the body 1 without reducing the movable ions in the part where the frame part 31 is anodically joined (the part outside the dashed line in FIG. 3A). The frame part 31 and the body 1 can be joined with sufficient joining strength. Here, if the silicon substrate 100 is etched by dry etching, there is an advantage that it is less affected by the crystal orientation of the silicon substrate 100 when the gap d is formed compared to other etching. On the one surface side of the body 1, a portion that is not anodically bonded at the time of the first bonding (when the silicon substrate 100 is bonded to the body 1), that is, a portion where the frame portion 31 is anodically bonded (FIG. 3A). ) And the portion where the silicon substrate 100 is anodically bonded (the portion inside the dashed line in FIG. 3A) can be visually recognized.

It is explanatory drawing explaining embodiment of the joining method which concerns on this invention. It is a disassembled perspective view of a micro relay same as the above. The body in a micro relay same as the above is shown, (a) is a front view, (b) is a sectional view taken along the line X-X 'in FIG. It is a back perspective view of the micro relay in the same as the above. (A) is a front view of an armature block in the micro relay of the above, and (b) is a rear view of the armature block in the micro relay of the above. It is a disassembled perspective view of the armature block in a micro relay same as the above. It is a perspective view of a body and a silicon substrate after the 1st time joining same as the above. It is a disassembled perspective view of the conventional micro relay.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body 3 Armature block 16 Storage hole 17 Cover body 30 Armature 31 Frame part 100 Silicon substrate

Claims (4)

A bonding method in which a semiconductor substrate is anodically bonded to one surface side of a flat glass substrate in a plurality of times, and is formed on the surface of the first semiconductor substrate before bonding the first semiconductor substrate to the glass substrate. Etching the surface of the glass substrate that opposes the one surface reduces the thickness of the first semiconductor substrate other than the portion to be bonded to the glass substrate, so that there is a gap between the glass substrate and the one surface. the spaced, the first semiconductor substrate to avoid the site of anodically bonding another semiconductor substrate after the one surface side of a glass substrate anodically bonded by the gap, the etching of the region corresponding to at least the gap after the anodic bonding A bonding method of a glass substrate and a semiconductor substrate , wherein the first semiconductor substrate is formed into a desired shape by performing . 2. The method for bonding a glass substrate and a semiconductor substrate according to claim 1, wherein the etching of the semiconductor substrate is dry etching . An electromagnet device that generates a magnetic attractive force in response to an exciting current to the coil, a body that is made of a glass substrate and that houses the electromagnet device, and has a fixed contact on one surface side in the thickness direction; and a semiconductor A frame-shaped frame portion made of a substrate and fixed to the one surface side of the body, an armature disposed inside the frame portion and supported to be swingable with respect to the frame portion, and an armature by a magnetic attraction force of an electromagnet device It has an armature block with a movable contact that contacts and separates from the fixed contact when it swings, and a cover that is made of a glass substrate and has a peripheral part fixed to the frame part on the opposite side of the body of the armature block. The electromagnet device is formed by closing a housing hole from the one surface side of the body with a lid made of a semiconductor substrate. Housing part for pay is provided a method of manufacturing a micro relay cover on the opposite side is anodically bonded to the frame portion and the body in the frame part with the frame part on the one surface side of the body is anodically bonded, Before joining the semiconductor substrate serving as the base of the lid body to the body, by etching the surface of the semiconductor substrate that faces the one surface of the body, other than the portion that becomes the lid body of the semiconductor substrate by reducing the thickness a gap between the one surface of the body portion of the semiconductor substrate by anodic bonding while avoiding a site at which the anodically bonded frame portion after the said one surface of the body by the gap, micro, characterized by forming the semiconductor substrate in the shape of the lid by etching the region corresponding to at least the gap after the anodic bonding Method of manufacturing a laser. 4. The method for manufacturing a micro relay according to claim 3, wherein the etching of the semiconductor substrate serving as a base of the lid is dry etching .

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