JP2000150915A - Semiconductor acceleration sensor chip and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of chips to be manufactured from one sheet of a wafer and to realize cost reduction of a semiconductor acceleration sensor chip. SOLUTION: This semiconductor acceleration sensor chip is constituted, wherein the sensor chip has one pair of fixing parts 11a and 11b split and arranged on the oppositely facing two sides of a square, a mass part 12, which is positioned between those fixing parts 11a and 11b and is supported by the fixing part 11a on one side of the fixing parts 11a and 11b via a hinge part 13, and one pair of stoppers 15 and 16, which are fixed both ends thereof by the fixing parts 11a and 11b, are arranged facing opposite both plate surfaces of the mass part 12 and are formed with electrode films 19 and 20 on the facing surfaces thereof. A pendulum part 14, consisting of the fixing parts 11 and 11b, the hinge part 13 and the mass part 12 arranged in a large number on a semiconductor substrate and are batch-formed, can be constituted small in size by the amount the component does not have for the fixing parts on the two sides of the square, in comparison with a conventional case having a frame- shaped fixed part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a configuration of a capacitance detection type acceleration sensor chip formed by using a semiconductor material and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 9 shows an example of a conventional structure of a semiconductor acceleration sensor chip of this kind. Fixed part 1 in the form of a rectangular frame
The mass part 12 is arranged in one frame, and the mass part 12 has a structure in which one side is cantilevered to the fixed part 11 via the hinge part 13. The pendulum part 14 including the fixing part 11, the mass part 12, and the hinge part 13 is integrally formed by etching a semiconductor material such as silicon.

A pair of stoppers 15 and 16 are provided so as to face both plate surfaces of the mass portion 12 having a substantially rectangular plate shape with a predetermined distance therebetween. The stoppers 15 and 16 are made of, for example, glass, and their peripheral edges are bonded and fixed to the fixing portion 11. In FIG. 9B, reference numerals 17 and 18 denote adhesives. Note that illustration of the stopper 15 is omitted in FIG. 9A.

Electrode films 19 and 20 are formed on the plate surfaces of the stoppers 15 and 16 facing the mass portion 12, respectively. Displacement of the mass portion 12 due to acceleration input is controlled by these electrode films 19 and 20. It can be detected by a change in capacitance with the unit 12. That is, the input acceleration is detected from the detected change in the capacitance. Note that excessive displacement of the mass portion 12 is suppressed by the stoppers 15 and 16.

In FIG. 9, reference numerals 21 to 23 denote electrode pads for wire bonding.
Is formed on one side of the fixing part 11 where the
1. Conductive with the mass section 12 via the hinge section 13. The electrode pad 22 is provided on the other side of the fixing portion 11.
Adhesive 1 which is formed insulated from and electrically conductive
The electrode 15 is electrically connected to the electrode film 19 of the stopper 15 located above via the electrode 7. On the other hand, the electrode pad 23 is
And is formed outside of the frame of the fixing portion 11 as shown in the figure. By performing wire bonding to these electrode pads 21 to 23, a wire (lead wire) is drawn out.

[0006]

In general, a large number of sensor chips having the above-described structure are manufactured by forming a large number of chips on a substrate (wafer) and then cutting them individually. That is, for example, by anisotropically etching a silicon substrate, a large number of pendulum portions 14 including the fixing portion 11, the mass portion 12, and the hinge portion 13 are simultaneously formed, and electrodes are formed on both surfaces of the silicon substrate in correspondence with each pendulum portion. After bonding and integrating the glass substrates for stoppers on which the films are arranged and formed, the sensor chip is cut out by dicing.

Therefore, for example, in order to manufacture a sensor chip at a lower cost, it is important that a larger number of sensor chips can be obtained from one wafer, that is, a smaller sensor chip can be obtained while maintaining the same sensitivity performance. A sensor chip is desired. In view of this point, an object of the present invention is to provide a semiconductor acceleration sensor chip that can be configured to be smaller, and to provide a preferable manufacturing method thereof.

[0008]

According to the first aspect of the present invention, a semiconductor acceleration sensor chip is provided between a pair of fixed portions divided on two opposite sides of a rectangle and between the fixed portions. The plate-shaped mass part supported on the fixed part via the hinge part, and both ends are fixed to the pair of fixed parts, and are arranged opposite to both plate surfaces of the mass part, respectively, and the electrode film is formed on the opposing surface. And a pair of fixing portions, hinge portions, and mass portions are integrally formed from the semiconductor substrate.

According to the second aspect of the present invention, a pair of fixed portions divided on two opposing sides of the rectangle and a pair of fixed portions are interposed between the fixed portions and supported by one of the fixed portions via the hinge portion. A semiconductor acceleration sensor chip comprising a plate-shaped mass portion and a pair of stoppers having both ends fixed to a pair of fixed portions, opposed to both plate surfaces of the mass portion, and electrode films formed on the opposed surfaces, respectively. A plurality of pendulum portions formed of a pair of fixed portions, hinge portions, and mass portions by etching a semiconductor substrate, and each pendulum portion is formed on both surfaces of the semiconductor substrate on which the pendulum portions are formed and formed. In a manufacturing method in which a pair of stopper substrates on which electrode films are arranged and formed corresponding to the parts are laminated and integrated, and then cut to cut out a semiconductor acceleration sensor chip, a fixed part and a material arranged and formed on the semiconductor substrate are cut. Parts are disconnected separately by cutting in the direction perpendicular to the both laminated and integrated after the two sides.

According to a third aspect of the present invention, in the second aspect of the present invention, the cutting in the direction orthogonal to the two sides is performed by grooving each surface of the semiconductor substrate through each stopper substrate and then removing the remaining portion. This is done by breaking.
According to a fourth aspect of the present invention, in the second aspect of the present invention, before the lamination and integration, the width of the electrode film formation surface of each stopper substrate is wider than the cutting width along the cutting position in a direction orthogonal to the two sides. A groove is formed.

According to a fifth aspect of the present invention, in the second aspect of the present invention, a sacrificial layer is provided on the electrode film of each stopper substrate before the lamination and integration, and the sacrificial layer is removed after the cutting. According to a sixth aspect of the present invention, in the second aspect of the present invention, before the lamination and integration, an electrode pad formed along one of the two sides and on the fixed portion is formed on one electrode film forming surface of the pair of stopper substrates. Opposing grooves are formed.

[0012]

Embodiments of the present invention will be described with reference to the accompanying drawings. Parts corresponding to those in FIG. 9 are denoted by the same reference numerals. FIG. 1 shows an embodiment of a semiconductor acceleration sensor chip according to the present invention, and FIG. 1A shows only a pendulum portion 14 thereof.
In this example, a pair of fixed portions 11a and 11b
The fixed portions 11a,
The mass 12 is located between 11b. The mass portion 12 is supported by the one fixed portion 11a via the hinge portion 13 in a cantilever manner.

The stoppers 15 and 16 having the electrode films 19 and 20 respectively have opposite ends at a pair of fixing portions 11.
The mass part 12 is opposed to both sides of the mass part 12 by being adhesively fixed to a and 11b. FIGS. 2A and 2B show the configuration of the surface of the stoppers 15 and 16 facing the mass portion 12.
And the stopper 16 has an electrode film 20.
Lead out the electrode pad 23.

The relay pad 19a of the stopper 15 is shown in FIG.
As shown in FIG.
It is electrically connected to the upper electrode pad 22. The electrode pad 2
2 is formed directly on the fixing part 11b, that is, unlike the conventional one shown in FIG. 9, the fixing part 11b is separated from the fixing part 11a on which the electrode pad 21 is formed, so that the insulation is not achieved. It is unnecessary.

A pair of fixing parts 11a, 11b, hinge part 1
The pendulum portion 14 including the mass 3 and the mass portion 12 is formed collectively by anisotropically etching a semiconductor substrate such as a silicon substrate. At this time, a large number of pendulum portions 14 are simultaneously arranged on the silicon substrate. And the pendulum part 1
Each pendulum part 1 is provided on both sides of a silicon substrate on which
After a pair of stopper substrates made of, for example, glass, which are formed by arranging the electrode films 19 and 20 so as to correspond to 4, respectively, are laminated and integrated by bonding, the semiconductor acceleration sensor chips are cut out and cut off individually. It is.

According to the configuration of the semiconductor acceleration sensor chip shown in FIG. 1, unlike the conventional semiconductor acceleration sensor chip shown in FIG. 9, the fixing portions 11a and 11b are not frame-shaped, but are Since only the two parts are arranged, even if they have the same sensitivity performance, that is, even if the mass parts 12 have the same size, there is no fixed part on the remaining two sides of the square, so that the structure is smaller than before. be able to.

FIG. 3 shows the basic steps up to lamination integration in the manufacture of the above-described semiconductor acceleration sensor chip for one sensor chip in the order of steps. Each step will be described below. (Step 1) SiO ₂ layers 3 on both sides of silicon substrate 31
2 is coated with a resist, a portion 33 for forming a penetrating portion is patterned, and the SiO ₂ layer 32 in that portion is removed by etching, and then the resist is removed. Then, the silicon substrate 31 is anisotropically etched using the SiO ₂ layer 32 as a mask to form a V-groove 34. (Step 2) A resist is applied, the portion 35 forming the hinge portion is patterned, and the SiO ₂ layer 32 in that portion is removed by etching, and then the resist is removed. (Step 3) The hinge portion 13 is formed by etching the silicon substrate 31 using the SiO ₂ layer 32 as a mask. At the same time, a penetrating portion 36 is formed in the V groove 34. (Step 4) After the SiO ₂ layer 32 is removed by etching, electrode pads 21 and 22 are formed. Electrode pads 21, 22
Has a three-layer structure of platinum silicide / Ti / Au, for example. (Step 5) Electrode films 19, 2 on both surfaces of silicon substrate 31
The glass substrates 37 and 38 each having the “0” formed thereon are respectively bonded. The bonding is performed at the fixing portions 11a and 11b,
A conductive adhesive 17 is used for bonding the upper glass substrate 37, and a general (non-conductive) adhesive 18 is used for bonding the lower glass substrate 38. The electrode film 19 (including the relay pad 19a) on the glass substrate 37 and the electrode film 20 (including the electrode pad 23) on the glass substrate 38 are both formed of, for example, two layers of Cr / Au.

FIG. 4A is a plan view of the state after the removal of the SiO ₂ layer 32 in the above-described step 4, that is, a plan view, in which a large number of pendulums are arranged on the silicon substrate 31 vertically and horizontally. The portion 14 is separated from the adjacent pendulum portion 14 by the penetrating portion 36 formed in the step 3 in the vertical direction (Y direction) orthogonal to the two sides formed by the fixed portions 11a and 11b, and is separated in one lateral direction (X direction). In (), it is in a state of being connected to the adjacent pendulum part 14.

The pendulum portions 14 adjacent to each other in the X direction are in a state where the fixed portions 11a and 11b are connected to each other, and furthermore, both ends 12a in the Y direction of the mass portion 12 are connected to each other. That is, the adjacent mass part 1
2A, as shown in FIG. 4A, both ends 12a in the Y direction.
Except for, the through portion 36 is formed by the above-described steps 1 to 3.

The fixed parts 11a and 11b to which the adjacent pendulum part 14 is connected and both ends 12a of the mass part 12 are cut and separated after lamination and integration with the glass substrates 37 and 38. Arrow 39 in FIG. 4B indicates the cutting position in the Y direction. According to the manufacturing method of the pendulum part 14 as described above, the mass parts 12 are connected and fixed to each other before the cutting step, and after the glass substrates 37 and 38 for stoppers are laminated and integrated, they are separated. They are individually separated.

That is, in the conventional structure shown in FIG. 9, when the etching of the silicon substrate is completed, each mass portion 12 is supported only by the hinge portion 13 and can be displaced, and there is no stopper glass substrate. In this example, the hinge portion 13 may be damaged due to excessive displacement. However, such an excessive displacement of the mass portion 12 during the manufacturing process is not generated by the above-described connection structure in this example. , Thereby preventing the hinge portion 12 from being damaged.

Next, a method for satisfactorily cutting in the Y direction will be described with reference to FIG. In the figure, reference numeral 41 denotes a dicing blade. In this method, the glass substrate 37,
Groove processing is performed by dicing on both surfaces of the silicon substrate 31 through 38. That is, the silicon substrate 31 is not completely cut by dicing, but a part thereof (a part shown by hatching in the drawing) is left as a connection remaining part 42. Then, the remaining portion 42 is cut by breaking.

This is because, when the silicon substrate 31 is completely cut by dicing, when the both ends 12a of the mass part 12 are cut off, a great force due to the dicing concentrates on the hinge part 13, and the hinge part 13 In order to avoid the problem of breakage, the hinge portion 13 is broken by applying a force to the integrated silicon substrate 31 and glass substrates 37 and 38 so as to curve the plate surfaces. The pendulum part 14 can be cut off individually by breaking the remaining part 42 without causing it. For example, in the case of a silicon substrate 31 having a thickness of 400 μm, the thickness of the remaining portion 42 is set to about 100 μm or less.

On the other hand, each of the electrode films 1 on the glass substrates 37 and 38
Before the lamination and integration, grooves 43 and 44 are formed along the cutting positions in the Y direction on the surfaces on which the layers 9 and 20 are formed. FIG. 6 shows the grooves 43 and 44 as viewed from the Y direction. The width of the grooves 43 and 44 is wider than the cutting width by dicing. As a numerical example, the thickness of the glass substrates 37 and 38 is, for example, 600 μm, while the width of the grooves 43, 44 is about 700 μm and the depth is about 400 μm. In addition,
The thickness of the dicing blade 41 is, for example, 100 μm.

By forming the grooves 43 and 44 as described above, chips (glass and silicon) due to dicing flow along the grooves 43 and 44, so that chips are placed in the sensor chip, that is, the mass portion. 12 and glass substrates 37, 3
8 can be reduced, thereby shortening the cleaning time of the sensor chip, for example.

FIG. 7 shows that the electrode films 19 and 20 of the glass substrates 37 and 38 are stained by dicing chips and dirt.
For example, it is possible to prevent chips from adhering or being embedded in the Au film, and furthermore, to prevent the mass part 12 and the electrode films 19 and 2 from being embedded.
This figure shows a structure for solving the problem that chips and the like remain in the gap with zero. In this example, before the lamination and integration, a sacrificial layer 45 is provided on each of the electrode films 19 and 20 of the glass substrates 37 and 38, and the sacrificial layer 45 is removed after cutting and cutting into each sensor chip. And The sacrificial layer 45 is formed of, for example, a resist or the like, and a solvent or the like is used for the removal. The sacrifice layer 45
May be smaller than the gap amount between the mass part 12 and the electrode films 19 and 20.

By adopting such a method, the electrode films 19 and 20 are protected by the sacrifice layer 45, and even if chips or the like enter between the mass portion 12 and the sacrifice layer 45, the sacrifice layer 45 is protected. With removal, it can be easily removed. The sacrifice layer 45 is not limited to a resist, and may be formed by, for example, a two-layer structure of Cr / Au.

Next, cutting in the X direction will be described. X
The cutting in the direction is performed by cutting the glass substrates 37 and 38 between the adjacent pendulum portions 14 as shown by a dashed line in FIG. As shown in FIG. 8, a groove 46 along the cutting position, that is, parallel to the X direction is formed on the upper surface of the glass substrate 37 on which the electrode film 19 is formed before lamination and integration.

As shown in FIG. 8, the groove 46 has a width facing the electrode pads 21 and 23 and the electrode pad 22 of the adjacent pendulum portion 14. Therefore, this groove 46
By dicing and removing the portion in which dicing is performed from the opposite side after lamination and integration, that is, from the back side, the upper portions of the electrode pads 21 to 23 are opened, and the wire bonding can be performed satisfactorily.

Conventionally, wires (lead wires)
A method is adopted in which a portion to be drawn out is formed in the glass substrate in advance by, for example, sandblasting.In this case, the portion other than the portion to be sandblasted must be protected with, for example, a mask, which is troublesome. is there. Since the processing accuracy of sandblasting is poor due to wraparound or the like, it is necessary to increase the size of the electrode pad, for example, to provide a margin, and thus the sensor chip also becomes larger. During lamination and integration, the silicon substrate and the glass substrate are generally held on a jig by a vacuum chuck. However, for a vacuum chuck for a glass substrate with holes, it is necessary to prepare a dedicated chuck, for example, which is time-consuming. , It is difficult to handle.

These problems have been solved by adopting a method in which grooving is performed in advance on the glass substrate 37 and the portion is removed by dicing from the opposite side as described above. can do. In the above-described embodiment, the lamination and integration of the silicon substrate 31 and the glass substrates 37 and 38 use the adhesives 17 and 18,
Although the bonding is performed, the method is not limited to this, and a method such as anodic bonding may be used.

[0032]

As described above, according to the first aspect of the present invention, the fixing portion for supporting the mass portion via the hinge portion is arranged only on two opposing sides of the square. Since the semiconductor acceleration sensor chip does not have a frame shape surrounding the four sides as described above, the semiconductor acceleration sensor chip can be made compact while maintaining the same sensitivity performance. Therefore, the number of sensor chips that can be made from one wafer can be increased, and the cost can be reduced accordingly. As a numerical example, for example, about 300 pieces of the φ4 inch substrate having the conventional structure can be obtained, while about 400 pieces can be obtained by adopting the present structure.

On the other hand, according to the second aspect of the invention, the mass parts of the pendulum parts are connected to each other and formed on the semiconductor substrate, and the stopper substrates are laminated and integrated and then individually cut off. Therefore, an excessive displacement does not occur in the mass part in the manufacturing process, and therefore, it is possible to prevent the hinge part from being damaged due to such an unexpected displacement.

Further, according to the third aspect of the present invention, the cutting in the direction of separating the connecting portion of the mass part in the cutting after the lamination and integration is performed by grooving and then removing the remaining portion of the semiconductor substrate left by the grooving. It is done by breaking at the end (break), so excessive force is not applied to the hinge part,
Damage failure of the hinge portion in this cutting step can be reduced.

According to the fourth aspect of the present invention, the chip is formed in the stopper substrate along the cutting position, so that the chip flows along the groove. Ingress can be reduced. Further, in the invention according to claim 5, the cutting is performed in a state where the sacrificial layer is present on the electrode film of the stopper substrate, and the sacrificial layer is removed after the cutting, so that the electrode film is protected, and the mass part is reduced. It is possible to solve the problem that the cutting powder or the like that has entered the gap with the electrode film remains as it is.

According to the invention of claim 6, since a groove is previously formed in a portion of the upper stopper substrate facing the electrode pad, the groove is removed after lamination and integration, so that the upper portion of each electrode pad is removed. Can be easily released and wire bonding can be performed satisfactorily. For example, a window (release portion) for drawing out a wire (lead wire) can be simplified compared to a conventional method in which a stopper substrate is formed using sandblasting. In addition, the upper release portion for drawing out the wire can be formed with high precision.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the invention of claim 1;
A is a plan view of a pendulum part, and B is a cross-sectional view of a completed sensor chip.

2A is a bottom view of the stopper 15 in FIG. 1, and FIG. 2B is a top view of the stopper 16 in FIG.

FIG. 3 is a process chart for explaining a basic manufacturing method of the sensor chip shown in FIG. 1;

FIG. 4A is a view for explaining a state where etching of a silicon substrate is completed, and FIG. 4B is a view showing a cutting position at which a pendulum portion is cut individually.

FIG. 5 is a view for explaining an embodiment of the invention of claim 3;

FIG. 6 is a diagram for explaining an embodiment of the invention of claim 4;

FIG. 7 is a diagram for explaining an embodiment of the invention of claim 5;

FIG. 8 is a diagram for explaining an embodiment of the invention according to claim 6;

FIG. 9 is a diagram showing a conventional semiconductor acceleration sensor chip, FIG.
Is a plan view omitting an upper stopper, and B is a cross-sectional view of a completed sensor chip.

Claims (6)

[Claims] 1. A pair of fixed portions divided on two opposite sides of a square, a plate-shaped mass portion positioned between the fixed portions and supported by one of the fixed portions via a hinge portion, Are fixed to the pair of fixing portions, and are disposed opposite to each other on both plate surfaces of the mass portion. The pair of stoppers each have an electrode film formed on the opposing surfaces. The pair of fixing portions and the hinge portion And a mass part integrally formed from a semiconductor substrate. 2. A pair of fixed portions divided on two opposite sides of a square, a plate-shaped mass portion positioned between the fixed portions and supported by one of the fixed portions via a hinge portion, and both ends. Are fixed to the pair of fixing portions, are disposed opposite to both plate surfaces of the mass portion, respectively, and are a pair of stoppers each having an electrode film formed on the opposing surface. By etching the semiconductor substrate, a large number of pendulum parts each including the pair of fixed parts, hinge parts and mass parts are arranged and formed, and the pendulum parts correspond to each pendulum part on both sides of the arranged semiconductor substrate. A method for manufacturing the semiconductor acceleration sensor chip by cutting and laminating a pair of stopper substrates on which the electrode films are arranged and formed, and cutting and fixing the fixed portions arranged and formed on the semiconductor substrate. The amount part,
A method for manufacturing a semiconductor acceleration sensor chip, wherein the semiconductor acceleration sensor chips are individually separated by cutting in a direction orthogonal to the two sides after the lamination and integration. 3. The method of manufacturing a semiconductor acceleration sensor chip according to claim 2, wherein said cutting in a direction perpendicular to said two sides is performed by grooving both surfaces of said semiconductor substrate through said stopper substrates. And a method of manufacturing the semiconductor acceleration sensor chip by breaking the remaining portion. 4. The method for manufacturing a semiconductor acceleration sensor chip according to claim 2, wherein, before the lamination and integration, the cutting position in a direction orthogonal to the two sides is formed on the electrode film forming surface of each of the stopper substrates. Forming a groove wider than the cutting width along the width thereof. 5. The method for manufacturing a semiconductor acceleration sensor chip according to claim 2, wherein a sacrificial layer is provided on the electrode film of each of the stopper substrates before the lamination and integration, and the sacrificial layer is removed after the cutting. A method for manufacturing a semiconductor acceleration sensor chip, comprising: 6. The method for manufacturing a semiconductor acceleration sensor chip according to claim 2, wherein, prior to the lamination and integration, the one side of the pair of stopper substrates is fixed to the electrode film forming surface along the two sides and along the two sides. A method for manufacturing a semiconductor acceleration sensor chip, wherein a groove facing an electrode pad formed on a portion is formed in advance.