JP2009167067A - Anodic bonding method for semiconductor sensor, anodic bonding device and semiconductor sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anodic bonding method for a semiconductor sensor by which in the positioning of a glass base and a sensor chip, even if the glass base is tilted, the corner part of the bottom face of the glass base is not damaged due to striking of the corner part against an installation stand, and a semiconductor sensor having a fine appearance can be produced. <P>SOLUTION: The upper face 35a of an installation stand 35 is provided with an installation face 36 on which a glass base 1 is installed. The installation face 36 is composed of the upper face of a base supporting part 37 projectingly provided so as to be located at the inside than the profile shape of the bottom face 1b in the glass base 1, and, even if the glass base 1 is tilted upon positioning, the corner part 1d or 1e of the bottom face in the glass base does not unevenly strike against the upper face 35a of the installation stand 35. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a semiconductor sensor anodic bonding method, an anodic bonding apparatus, and a semiconductor sensor.

  Conventionally, in the manufacture of a semiconductor sensor, for example, a semiconductor pressure sensor, in order to improve the yield, a non-defective sensor chip cut out from a silicon wafer and a glass wafer and a glass base are individually anodically bonded. (For example, see Patent Documents 1 and 2).

  10 to 12 are views showing a conventional positioning mechanism used for positioning a glass base and a sensor chip of a semiconductor pressure sensor, FIG. 10 is a plan view, and FIG. 11 is a line XI-XI in FIG. Sectional drawing and FIG. 12 are perspective views of a pressing means. In these figures, 1 is a square glass base in plan view, 2 is a square sensor chip anodically bonded to the upper surface of the glass base 1, 3 is a silicon tube previously anodically bonded to the lower surface of the glass base 1, Reference numeral 4 denotes an installation base on which the glass base 1 is installed. Reference numeral 5 denotes the glass base 1 and the sensor chip 2 by pressing the side surfaces 1c and 2c of the sensor chip 2 in a direction perpendicular to the side surfaces. A pressing member (pressing means). After the glass base 1 and the sensor chip 2 are pressed and positioned by the pressing member 5, the semiconductor pressure sensor 7 is manufactured by anodically bonding the joining surface 6 of the glass base 1 and the sensor chip 2 with an anodic bonding apparatus. .

  The anodic bonding method is a direct bonding method in which a third material is not interposed between bonding members. In the manufacture of a semiconductor sensor, glass and silicon having a similar coefficient of thermal expansion are overlapped, and the glass side is minus, silicon By applying a DC voltage of about 300 to 700 V with the side being positive and heating at the same time, the positive ions (for example, Na +, K +) on the glass side are forcibly diffused to the negative electrode side, and a strong electrostatic attraction between them. Is a bonding method in which glass and silicon are chemically bonded.

Japanese Patent No. 3895937 Japanese Patent No. 3359493

  However, when the glass base 1 and the sensor chip 2 are positioned by the conventional positioning mechanism 10 described above, when the glass base 1 and the side surfaces 1c and 2c of the sensor chip 2 are pressed and positioned by the pressing member 5, the glass There was a problem that the bottom corner of the base 1 was easily damaged (chipped). That is, when a square glass base 1 is manufactured by dicing a glass wafer, the side surface 1c of the glass base 1 is not perpendicular to the top surface 1a and the bottom surface 1b due to blurring of a dicing blade. As shown to 13 (a), the two side surfaces 1c and 1c 'which oppose each other may incline to the right side. In such a case, when the pressing member 5 is pressed and positioned on each side surface of the glass base 1 from four directions, the inclined side surfaces 1c and 1c ′ of the glass base 1 try to follow the pressing surface 5a of the pressing member 5. Therefore, as shown in FIG. 13B, the glass base 1 is inclined to the left side, that is, the side opposite to the inclined side of the side surfaces 1c and 1c ′, with the contact portion P with the pressing member 5 as a fulcrum. For this reason, the bottom corner 1d opposite to the tilt side of the glass base 1 is lifted from the upper surface 4a of the installation table 4, and the bottom corner 1e on the inclined side hits the upper surface 4a of the installation table 4. As a result, the load concentrates on the bottom corner 1e, and the bottom corner 1e is damaged by this load.

  Even if the side surface 1c of the glass base 1 is not tilted, the glass base may be tilted due to an attachment error of the pressing member 5, a processing error of the pressing surface 5a that presses the glass base 1, or the like. Since the table 1 is inclined, the bottom corners may be damaged.

  The present invention has been made to solve the above-described conventional problems. The object of the present invention is to position the glass base and the sensor chip, even if the glass base is tilted, the bottom corner is the installation base. An anodic bonding method, an anodic bonding apparatus, and a semiconductor sensor for a semiconductor sensor, which can manufacture a semiconductor sensor with good quality without causing any damage to the upper surface of the semiconductor sensor.

  In order to achieve the above object, the anodic bonding method for a semiconductor sensor according to the present invention is a method of installing a square glass base in plan view on an installation base, and further mounting a square sensor chip on the glass base, In the anodic bonding method of a semiconductor sensor, in which the glass base and the side surface of the sensor chip are pressed and positioned by pressing means, and then the bonding surface of the glass base and the sensor chip is anodically bonded. The installation surface on which the base is installed is formed on a surface that supports the inside from the bottom corners of the glass base.

  In the anodic bonding apparatus according to the present invention, a glass base having a square shape in plan view is installed on an installation base, and a square sensor chip is placed on the glass base, and the glass base and the sensor chip are mounted. In the anodic contact apparatus for a semiconductor sensor, in which the glass base of the installation base is installed in the anodic contact apparatus for anodic bonding of the joint surface of the glass base and the sensor chip after the side surface is pressed by the pressing means Is formed on a surface that supports the inner side of each bottom corner of the glass base.

  The anodic bonding apparatus according to the present invention is characterized in that, in the above invention, the installation surface of the installation table is formed smaller than the contour shape of the bottom surface of the glass base.

  Further, the anodic bonding apparatus according to the present invention is the anodic bonding apparatus according to the above invention, wherein the installation surface of the installation table protrudes on the installation table so that the installation surface of the installation table is located inside the bottom corner of the glass table. It is characterized by comprising an upper surface.

  Moreover, the anodic bonding apparatus according to the present invention is characterized in that, in the above-mentioned invention, the base support portion is constituted by a frame-like protruding body.

  Moreover, the anodic bonding apparatus according to the present invention is the anodic bonding apparatus according to the above-mentioned invention, wherein the base support part is a four projecting body projecting so as to be located inside each bottom corner of the bottom surface of the glass base. It is characterized by being comprised.

  Furthermore, the semiconductor sensor according to the present invention is manufactured by the anodic bonding method.

  In the present invention, since the installation surface on which the glass base of the installation base is installed is formed on a surface that supports the inside from the bottom corners of the glass base, the glass base and the sensor chip are pressed by pressing means. Even when the glass base is tilted when positioned, the bottom corners on the tilt side do not come into contact with the installation surface of the installation table, and damage to the bottom corners can be prevented.

  As the surface on which the installation surface of the installation base supports the inside of each bottom corner of the glass base, use an installation base whose upper surface itself is smaller than the bottom area of the glass base, and use the upper surface of this installation base as the installation surface If the base support part located inside the bottom corner of the bottom surface of the glass base is provided on the top surface of the installation base and the upper surface of this base support part is used as the installation surface of the glass base, Even if the table is tilted, the bottom corners on the tilt side do not come into contact with the installation table, and damage to the bottom corners can be prevented.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is a plan view showing an embodiment of a semiconductor sensor manufactured according to the present invention, FIG. 2 is a front view of the semiconductor sensor, and FIG. 3 is a sectional view taken along line III-III in FIG. This embodiment shows an example in which a semiconductor pressure sensor is applied as a semiconductor sensor. Further, the same components and parts as those shown in the prior art column are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. In these drawings, a semiconductor pressure sensor generally indicated by reference numeral 7 includes a glass base 1 having a square shape in plan view, a silicon sensor chip 2 anodically bonded to the upper surface of the glass base 1, and a glass base. The sensor has a three-layer structure including a silicon tube 3 anodically bonded to the lower surface of 1.

The glass base 1 is the same as the conventional glass base 1 shown in FIGS. 10 and 11, and has a linear expansion coefficient (5 to 7 × substantially equal to the linear expansion coefficient (4.2 × 10 ⁻⁶ ) of silicon. 10 ⁻⁶ ) Pyrex (registered trademark) glass, ceramics or the like is formed into a square columnar body in plan view and has a center hole 20 penetrating the front and back surfaces formed in the center. Further, a stepped portion 31 having a triangular shape in plan view is formed at each corner on the upper surface 1a of the glass base 1, and the corner of the sensor chip 2 is not joined to the glass base 1 by the stepped portion 31. A junction 2D is formed. However, the stepped portion 31 is not limited to the one formed on the glass base 1 side, but is formed on the lower side of the corner of the thick portion 2B of the sensor chip 2, and the corner of the sensor chip 2 is formed on the glass base 1. It is good also as a non-joining part.

  The sensor chip 2 is the same as the conventional sensor chip 2 shown in FIGS. 10 and 11, and is formed of p-type single crystal Si having a (100) crystal plane orientation. The sensor chip 2 is a square chip whose plan view is slightly smaller than that of the glass base 1, and the central portion of the upper surface 2a is formed of a thin portion by forming a concave portion 32 by etching in the central portion of the lower surface 2b. A diaphragm 2A is formed, and the outer portion of the diaphragm 2A forms a thick portion 2B.

  The diaphragm 2A is a quadrangle, and is formed in a state of being inclined by 45 ° with respect to the sensor chip 2 so that the two diagonal lines a and a intersect the diagonal lines b and b of the sensor chip 2 at an angle of 45 °. Four differential pressure or pressure detection gauges 14a to 14d that act as piezo regions and detect differential pressure or pressure are formed in the vicinity of the peripheral edge so as to be positioned on the diagonal lines b and b of the sensor chip 2. The gauges 14a to 14d are formed in the <110> crystal axis direction where the piezoresistance coefficient is maximum in the crystal plane orientation (100) of the sensor chip 2.

  Moreover, the part joined to the upper surface 1a of the glass base 1 in the thick part 2B of the sensor chip 2 forms an octagonal joint 2C, and the other part is relative to the step part 31 of the glass base 1. Thus, the non-joining portion 2D is formed.

  The joint surface 33 of the sensor chip 2 and the glass base 1 is related to the deformation of the diaphragm 2A, and when the square diaphragm 2A is formed at an angle of 45 ° with the diagonal lines orthogonal to the square sensor chip 2, Of the joint surfaces of the sensor chip 2, the length of the joint surface in the diagonal line b direction is long. Therefore, when the entire lower surface of the thick portion 2B is joined, the stress σr perpendicular to the side of the diaphragm 2A becomes the stress σθ parallel to the side of the diaphragm 2A. Become bigger. Therefore, the non-joint portion 2D is provided and the ratio A / B between the length A and the length B of the joint portion 2C is optimized so that the stress σr and the stress σθ are substantially equal.

  Furthermore, on the upper surface 2a of the sensor chip 2 on the upper surface of the thick portion 2B corresponding to the non-bonded portion 2D, a static pressure is detected and a detection signal of the differential pressure or pressure detection gauges 14a to 14d is detected by the detection signal. There are provided four static pressure detection gauges 15a to 15d for correcting the above. These static pressure detection gauges 15 a to 15 d are provided so as to be located at respective corners on the diagonal lines b and b of the sensor chip 2. Further, the sensor chip 2 is long in the <110> crystal axis direction where the piezoresistance coefficient is maximum in the crystal plane orientation (100). The static pressure detecting gauges 15a to 15d are formed by diffusion or ion implantation similarly to the differential pressure or pressure detecting gauges 14a to 14d, and are connected to a Wheatstone bridge by leads (not shown). The static pressure is detected by changing the specific resistance with the deformation of the non-joint portion 2D due to the pressure, and the detection signal of the differential pressure or the pressure detection sensors 14a to 14d is corrected by the detection signal.

  The silicon tube 3 is formed in a cylindrical body having an outer diameter inscribed in the glass base 2, and a pressure introducing hole 21 is formed in the center. Such a silicon tube 3 is anodically bonded to the bottom surface 1 b of the glass base 1 before the silicon chip 2.

When anodically bonding the glass base 1 and the silicon tube 3, the glass base 1 is placed on the silicon tube 3, and a voltage is applied to the glass base 1 and the silicon tube 3 while heating to a predetermined temperature. Anodized. That is, a negative electrode is attached to the glass base 1, a positive electrode is attached to the silicon tube 3, and a DC voltage of about 300 to 700V is applied and simultaneously heated to 200 to 400 ° C. (For example, Na ⁺ , K ′) is forcibly diffused to the negative electrode side, and electrostatic attraction is generated between the glass base 1 and the silicon tube 3 to anodic bond the glass base 1 and the silicon tube 3. .

  After the glass base 1 and the silicon tube 3 are anodically bonded, the glass base 1 and the sensor chip 2 are subsequently anodically bonded in the same manner.

  When anodically bonding the glass base 1 and the sensor chip 2, the glass base 1 and the sensor chip 2 are previously positioned by the positioning mechanism 40 shown in FIGS. 4 to 6, and then the anodic bonding apparatus 50 shown in FIG. 9. Anodized by.

  4 to 6, the positioning mechanism 40 includes an installation table 35 and four pressing members 5 as pressing means for pressing the side surfaces 1 c and 2 c of the glass base 1 and the sensor chip 2. . The pressing member 5 has the same shape as the conventional pressing member 5 shown in FIGS. 10 and 11, and the circumference of the installation table 35 is arranged above the installation table 35 so as to face the glass base 1 and the sensor chip 2. It is arranged so as to be able to advance and retract by shifting the phase by 90 ° in the direction. Further, two pressing portions 5A and 5B for pressing the side surface 1c of the glass base 1 and the side surface 2c of the sensor chip 2 are provided on the surfaces of the pressing members 5 facing each other. The pressing surfaces of these pressing portions 5A and 5B are formed as vertical surfaces.

  The installation table 35 is formed in a cylindrical shape by the same material (for example, ceramics such as silicon nitride and alumina) as the conventional installation table 4 shown in FIGS. The installation surface to be installed is different. That is, the conventional installation table 4 has the entire upper surface 4 a formed on the same plane larger than the area of the bottom surface of the glass base 1 as the installation surface of the glass base 1. The installation surface 36 on which the glass base 1 is installed is formed on a surface where the corners 5a to 5d on the bottom surface of the glass base 1 do not come into contact with each other even if the glass base 1 is inclined during positioning.

  5 is formed in a cylindrical shape having an outer diameter larger than the diagonal length of the glass base 1 and a center hole 38 into which the silicon tube 3 is inserted. Moreover, the upper surface 35a of the installation base 35 is formed in the horizontal plane which has an area larger than the bottom face 1b of the glass base 1, and this upper surface 35a is inside the outline shape of the bottom face 1b of the glass base 1, Four base support portions 37 located on the inner side of each corner of the bottom surface 1b are projected, and the upper surface of the base support portion 37 is formed as a horizontal flat surface, and the installation surface on which the glass base 1 is installed. 36. The base support portion 37 is configured by a relatively small protrusion having a triangular shape in plan view. That is, in the present invention, the base support portion 37 is projected from the 35th upper surface 35a of the installation, and the upper surface is used as the installation surface 36.

  4 to 6, four base support portions 37 are formed on the upper surface 35a of the installation base 35 around the center hole 38 at intervals of 90 °. As shown, it may be formed by one continuous base support part 39. That is, in FIG. 7, a circular frame-like base support portion 39 smaller than the contour shape of the bottom surface 1b of the glass base 1 is provided on the upper surface 35a of the installation base 35 so as to protrude around the center hole 38. The bottom surface 1b of the glass base 1 is supported using the upper surface of 39 as an installation surface. The base support portion 39 is not limited to a circular frame shape, and may be a square frame shape smaller than the contour shape of the bottom surface 1 b of the glass base 1. Moreover, as another embodiment, the planar view shape of the installation table 35 may be formed smaller than the bottom surface 1b of the glass base 1, and the entire upper surface may be used as the installation surface. In this case, the bottom corner of the glass base 1 protrudes laterally from the top surface 35a of the installation table 35, so that the bottom corner hits the top surface 35a of the installation table 35 even if the glass pedestal 1 is tilted. There is nothing wrong.

  In short, the installation table 35 only needs to have an installation surface where the bottom corners do not come into contact with the installation table 35 when the glass base 1 is tilted during positioning.

  When the glass base 1 and the sensor chip 2 are positioned by the positioning mechanism 40, the glass base 1 is installed on the base support portion 37 (or 39) of the installation base 35. Further, after the sensor chip 2 is placed on the sensor chip 2 so that the corners coincide with each other, both members are positioned by the pressing member 5. That is, each pressing member 5 is moved in a direction approaching each other, the pressing portions 5A and 5B are pressed against the side surfaces 1c and 2c of the glass base 1 and the sensor chip 2, respectively, and the glass base 1 and the sensor chip 2 are positioned. To do.

  At this time, if two opposing side surfaces 1c and 1c ′ of the glass base 1 are inclined in the same direction rather than perpendicular to the top surface 1a and the bottom surface 1b as shown in FIG. When 1 is pressed, the inclined side surfaces 1c and 1c 'of the glass base 1 try to follow the pressing surface 5a of the pressing member 5, so that the glass base 1 has the contact portion with the pressing member 5 as a fulcrum. 1c ′ is inclined to the opposite side (inclined to the left side in FIG. 8). For this reason, the bottom corner 1 d on the side opposite to the tilt side of the glass base 1 floats above the installation table 35, and the bottom corner 1 e on the tilt side becomes lower than the installation surface 36 of the base support 37. However, since a step 43 is formed between the upper surface 35 a of the installation table 35 and the installation surface 36 of the base support unit 37, the bottom corner 1 e remains on the upper surface of the installation table 35 even when the glass base 1 is tilted. There is no chance of hitting 35a. Therefore, there is no possibility that the bottom corner 1e is damaged, and the glass base 1 and the sensor chip 2 can be satisfactorily positioned.

  When the positioning operation of the glass base 1 and the sensor chip 2 by the positioning mechanism 40 is finished, the pressing state of the pressing member 5 against the glass base 1 and the sensor chip 2 is released, and the glass base 1 and the sensor chip 2 are anodically bonded. .

  When the anodic bonding of the glass base 1 and the sensor chip 2 by the anodic bonding apparatus 50 is performed, the anodic bonding is performed by the side electrode method as shown in FIG. That is, the plus electrode 51 is connected to the upper surface of the sensor chip 2, the minus electrode 52 is connected to each side surface 1 c of the glass base 1, and the electrodes 51 and 52 are connected to the power source 53. When a 300 to 700 V DC voltage is applied between the electrodes 51 and 52 and the glass base 1 and the sensor chip 2 are heated to 200 to 400 ° C., the cations in the glass base 1 are forcibly diffused. As a result, an electrostatic attractive force is generated between the joint portions 33 of the glass base 1 and the sensor chip 2 to anodic bond these two members.

  Thus, in the present invention, when the installation surface 36 on which the glass base 1 of the installation base 35 is installed is provided above the upper surface 35a and the glass base 1 and the sensor chip 2 are positioned, the glass base 1 is Since the bottom corners do not come into contact with the top surface 35a even if tilted, the bottom corners can be prevented from being damaged during positioning, and the semiconductor pressure sensor 7 having good quality and appearance can be manufactured. it can.

  In the above embodiment, an example in which the semiconductor pressure sensor 7 is applied as a semiconductor sensor has been described. However, the present invention is not limited to this, and is applied to an acceleration sensor, a differential pressure / pressure sensor, and the like. It can also be applied to capacitive sensors instead of resistive ones.

It is a top view which shows one Embodiment of the semiconductor sensor manufactured by this invention. It is a front view of a semiconductor sensor. It is the III-III sectional view taken on the line of FIG. It is a top view which shows a positioning mechanism. It is sectional drawing of a positioning mechanism. It is a perspective view of an installation stand. It is a perspective view which shows other embodiment of an installation stand. It is a figure which shows the inclination of the glass base at the time of positioning. It is sectional drawing which shows the state which is performing anodic bonding. It is a top view which shows the conventional positioning mechanism. It is the XI-XI sectional view taken on the line of FIG. It is a perspective view of a pressing member. (A), (b) is a figure for demonstrating the damage by the one piece contact of the bottom face corner of the glass base at the time of positioning.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Glass base, 2 ... Sensor chip, 3 ... Silicon tube, 5 ... Pressing member (pressing means), 33 ... Joining surface, 35 ... Installation base, 36 ... Installation surface, 37, 39 ... Base support part, 40 ... positioning mechanism, 41 ... plus electrode, 42 ... minus electrode, 43 ... power source, 50 ... anodic bonding apparatus.

Claims (7)

A square glass base is installed on the installation base, and a square sensor chip is placed on the glass base, and the glass base and the side surfaces of the sensor chip are pressed and positioned by pressing means. After, in the anodic bonding method of the semiconductor sensor for anodic bonding the bonding surface of the glass base and the sensor chip,
The method for anodic bonding of a semiconductor sensor, wherein an installation surface on which the glass base of the installation base is installed is formed on a surface that supports the inner side of each bottom corner of the glass base. A square glass base is installed on the installation base, and a square sensor chip is placed on the glass base, and the glass base and the side surfaces of the sensor chip are pressed and positioned by pressing means. After, in the anodic contact apparatus of the semiconductor sensor for anodic bonding the joint surface of the glass base and the sensor chip,
An anodic bonding apparatus, wherein an installation surface on which the glass base of the installation base is installed is formed on a surface that supports an inner side from each bottom corner of the glass base. The anodic bonding apparatus according to claim 2, wherein
The anodic bonding apparatus characterized in that the installation surface of the installation table is formed smaller than the contour shape of the bottom surface of the glass base. The anodic bonding apparatus according to claim 2, wherein
The installation surface of the installation table is configured by an upper surface of a base support part projecting on the installation table so as to be positioned on the upper surface of the installation table and inside the bottom corner of the glass base. Anodic bonding equipment. The anodic bonding apparatus according to claim 4, wherein
The anodic bonding apparatus is characterized in that the base support portion is constituted by a frame-like protrusion. The anodic bonding apparatus according to claim 4, wherein
The said base support part is comprised by the four protrusions protrudingly provided so that it might each be located inside each bottom corner of the bottom face of a glass base, The anodic bonding apparatus characterized by the above-mentioned.   A semiconductor sensor manufactured by the anodic bonding method according to claim 1.

Images