CN115201516A

CN115201516A - Acceleration detection device

Info

Publication number: CN115201516A
Application number: CN202210876158.XA
Authority: CN
Inventors: 丁海涛
Original assignee: Zhunmao Hangzhou Technology Co ltd
Current assignee: Zhunmao Hangzhou Technology Co ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2022-10-18

Abstract

The present disclosure provides an acceleration detection apparatus, including a substrate; the mass block is positioned above the substrate and is separated from the substrate; the capacitance group is connected with the mass block, and the capacitance value of the capacitance group is changed along with the displacement of the mass block in the first direction; the isolation structure is elastically connected with the mass block along a first direction; the first supporting structure and the second supporting structure are respectively positioned on two sides of the mass block along the first direction and are respectively and elastically connected with the isolation structure along the second direction, the thickness directions of the first supporting structure, the second supporting structure and the substrate are mutually vertical, the first supporting structure and the second supporting structure respectively comprise a first bonding part and a second bonding part, the first supporting structure and the second supporting structure are respectively and fixedly connected with the substrate through the first bonding part and the second bonding part, the connecting line of the first bonding part and the second bonding part is relatively vertical to the first direction, and the stress generated by mismatch of thermal expansion coefficients among bonding materials is released through the elastic connection of the supporting structure and the isolation structure, so that the performance of the acceleration detection device is improved, and the flexibility of processing material selection is increased.

Description

Acceleration detection device

Technical Field

The present disclosure relates to the field of semiconductor device manufacturing, and more particularly, to an acceleration detection apparatus of a MEMS structure.

Background

Devices manufactured based on Micro Electro Mechanical Systems (MEMS) technology are called MEMS devices, wherein in the processing of acceleration detection devices different materials are often used for bonding, for example, silicon-glass bonding process is widely used due to the excellent insulating property of quartz glass and the thermal expansion coefficient closer to that of silicon material. However, because the thermal expansion coefficients of the two materials still have a certain mismatch, when the temperature changes, thermal stress can be generated, so that the mass block of the MEMS acceleration detection device deviates from the equilibrium position, the zero drift problem is caused, and the performance of the acceleration detection device is reduced.

Accordingly, it is desirable to provide an improved acceleration detection apparatus to improve the performance of a product.

Disclosure of Invention

In view of this, the present disclosure provides an improved acceleration detection apparatus, which releases stress generated by mismatch of thermal expansion coefficients between bonding materials through elastic connection between a support structure and an isolation structure, and improves the problem of zero drift, thereby improving the performance of the acceleration detection apparatus and increasing the flexibility of material selection.

According to the acceleration detection device that this disclosed embodiment provided, include: a substrate; a mass located above the substrate and spaced apart from the substrate; at least one capacitor bank connected to the mass block, the capacitance value of the capacitor bank changing with the displacement of the mass block in a first direction; the isolation structure is elastically connected with the mass block along the first direction; and the first supporting structure and the second supporting structure are respectively positioned on two sides of the mass block along the first direction and are respectively and elastically connected with the isolation structure along the second direction, the first direction, the second direction and the thickness direction of the substrate are mutually vertical, wherein the first supporting structure comprises a first bonding part and a first main body part which are connected, the second supporting structure comprises a second bonding part and a second main body part which are connected, the first supporting structure and the second supporting structure are respectively connected with the substrate through the first bonding part and the second bonding part, and the connecting line of the first bonding part and the second bonding part is relatively vertical to the first direction.

Optionally, the method further comprises: two ends of the first elastic beam are respectively connected with the isolation structure and the first main body part; and a second elastic beam, both ends of which are connected with the isolation structure and the second main body part respectively.

Optionally, the isolation structure is ring-shaped, and surrounds the mass block and the capacitor bank.

Optionally, the first bonding part is made of a different material from the substrate and is bonded and connected with the substrate; and/or the second bonding part is made of a material different from that of the substrate and is bonded and connected with the substrate.

Optionally, the first bonding part is made of a different material than the first main body part and is bonded to the first main body part; and/or the second bonding part is made of a material different from that of the second main body part and is bonded and connected with the second main body part.

Optionally, along the second direction, the first elastic beam corresponds in position to the first key portion, and the second elastic beam corresponds in position to the second key portion.

Optionally, the first main body portion and the second main body portion both extend along the first direction, the first elastic beams are plural and distributed on two sides of the first bonding portion along the second direction, and the second elastic beams are plural and distributed on two sides of the second bonding portion along the second direction.

Optionally, the first elastic beam and the second elastic beam are symmetrically distributed on two sides of the isolation structure along the first direction, the first bonding portion is located in the middle of the first main body portion, the plurality of first elastic beams are symmetrically distributed on two sides of the first bonding portion along the second direction, the second bonding portion is located in the middle of the second main body portion, and the plurality of second elastic beams are symmetrically distributed on two sides of the second bonding portion along the second direction.

Optionally, each of the capacitance banks includes: at least one pair of first capacitor plates distributed on two sides of the mass block along the first direction; and a second capacitive plate corresponding to each of the first capacitive plates, wherein each of the first capacitive plates is connected to the proof mass, and each of the second capacitive plates is fixed relative to the substrate and spaced apart from the proof mass.

Optionally, the isolation structure further includes a plurality of third elastic beams distributed on two sides of the mass block along the second direction, and respectively connecting the mass block and the isolation structure.

Optionally, the plurality of third elastic beams are symmetrically distributed on two sides of a central axis of the mass block along the first direction, and the central axis is relatively parallel to the first direction.

In the structural design of the acceleration detection device, a stress-releasing isolation structure which can move in a second direction perpendicular to the first direction (an acceleration sensitive direction or a motion direction of a mass block) is configured, the isolation structure is respectively elastically connected with the mass block and a first support structure and a second support structure, the first support structure and the second support structure are respectively provided with a bonding part as an anchoring part and are fixedly connected with a substrate, and the coordinates of the two anchoring parts in the first direction are basically consistent. When the temperature changes, due to the difference of the thermal expansion coefficients between the two materials of the bonding, the change lengths of the expansion or contraction to the free state are different, so that under the constraint of the bonding part, the first and second support structures can be subjected to tensile or compressive stress, and the first and second support structures are deviated from the equilibrium position. Because the coordinates of the two bonding parts in the first direction are basically consistent, the stress generated in the first direction is almost zero, and the stress is generated in the second direction, so that the first supporting structure and the second supporting structure are displaced in the second direction, and the elastic connecting part connected with the first supporting structure and the second supporting structure is deformed, thereby releasing the stress, improving the problem of zero drift, and further increasing the flexibility of processing material selection.

Furthermore, although the acceleration detection device structure cannot be completely symmetrical due to the existence of processing errors, the elastic coefficients of the first elastic beam and the second elastic beam are different, and the deformation is not completely consistent, so that the isolation structure generates small displacement along the second direction, and the capacitance values of the capacitor groups are kept unchanged by configuring the capacitor plates on the two sides of the mass block, thereby achieving the purpose of keeping the zero position of the acceleration detection device unchanged.

Therefore, the acceleration detection device provided by the disclosure can improve the performance of a product.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description only relate to some embodiments of the present disclosure and do not limit the present disclosure.

Fig. 1 shows a schematic perspective view of an acceleration detection device according to a first embodiment of the present disclosure.

Fig. 2 is a schematic top view of an acceleration detection device according to a first embodiment of the present disclosure.

Fig. 3 shows a schematic cross-sectional structure taken along line AA in fig. 1.

Fig. 4 is a schematic top view showing an acceleration detection device according to a second embodiment of the present disclosure.

Detailed Description

The present disclosure will be described in more detail below with reference to the accompanying drawings. Like elements are denoted by like reference numerals throughout the various figures. For purposes of clarity, the various features in the drawings are not drawn to scale. In addition, certain well known components may not be shown. For simplicity, the semiconductor structure obtained after several steps can be described in one figure.

It will be understood that when a layer or region is referred to as being "on" or "over" another layer or region, it can be directly on the other layer or region or intervening layers or regions may also be present in the structure of the device. And, if the device is turned over, that layer, region, or regions would be "under" or "beneath" another layer, region, or regions.

If the description is directed to the case of directly on another layer or another region, the description will be made by "directly on 8230; \8230; above or" on 8230; \8230; above and adjacent to the former "and so on.

Numerous specific details of the present disclosure, such as structures, materials, dimensions, processing techniques and techniques of the devices, are set forth in the following description in order to provide a more thorough understanding of the present disclosure. However, as will be understood by those skilled in the art, the present disclosure may be practiced without these specific details.

The present disclosure may be presented in various forms, some examples of which are described below.

Fig. 1 shows a schematic perspective structure diagram of an acceleration detection device according to a first embodiment of the present disclosure, fig. 2 shows a schematic top-view structure diagram of the acceleration detection device according to the first embodiment of the present disclosure, and fig. 3 shows a schematic cross-sectional structure diagram taken along line AA in fig. 1.

As shown in fig. 1 to 3, the acceleration detection device of the present disclosure includes: the capacitive array comprises a substrate 101, a mass block 1, a third elastic beam 2, a first elastic beam 3, a second elastic beam 4, an isolation structure 5, a capacitor bank, a first support structure 6 and a second support structure 9.

In the present embodiment, the proof mass 1 is located above the substrate 101 and separated from the substrate 101. The capacitor bank is connected with the mass block 1, the capacitance value of the capacitor bank changes along with the displacement of the mass block 1 in the X-axis direction (first direction), and the displacement of the mass block 1 is in direct proportion to the acceleration. Wherein each capacitor bank comprises: at least one pair of first capacitor plates 7 distributed on two sides of the mass block 1 along the X-axis direction; and a second capacitor plate 8 corresponding to each first capacitor plate 7. Each first capacitive plate 7 is connected to the mass 1 and each second capacitive plate 8 is fixed with respect to the substrate 101 and spaced from the mass 1. In some specific embodiments, the number of capacitor banks is plural; each capacitor bank further comprises a connecting portion 10, the connecting portion 10 is fixedly connected with the substrate 101 by bonding, and each connecting portion 10 connects each second capacitor plate 8 in the corresponding capacitor bank in parallel. The isolation structure 5 is elastically connected with the mass block 1 along the X-axis direction, wherein the isolation structure 5 is annular and surrounds the mass block 1 and the capacitor bank. In some specific embodiments, the isolation structure 5 is in the shape of a rectangular ring or a square ring. The first supporting structure 6 and the second supporting structure 9 are respectively located at two sides of the mass block 1 along the X-axis direction, and are respectively elastically connected with the isolation structure 5 along the Y-axis direction (second direction), and the X-axis direction, the Y-axis direction and the Z-axis direction (thickness direction of the substrate 101) are perpendicular to each other. The first supporting structure 6 includes a first main body portion 61 and a first bonding portion 62, the second supporting structure 9 includes a second main body portion 91 and a second bonding portion 92, the first supporting structure 6 and the second supporting structure 9 are respectively and fixedly connected to the substrate 101 through the first bonding portion 62 and the second bonding portion 92, and a connection line of the first bonding portion 62 and the second bonding portion 92 is relatively perpendicular to the X-axis direction. In order to more clearly express the first and second supporting structures 6 and 9, the first and

second bonding portions

62 and 92 which should be hidden originally are shown in fig. 2.

In some specific embodiments, the first bonding portion 62 material may be identical to the substrate 101 or identical to the first main body portion 61, and the second bonding portion 92 material may be identical to the substrate 101 or identical to the second main body portion 91, wherein the materials of the first main body portion 61 and the second main body portion 91 include, but are not limited to, silicon, and the material of the substrate 101 includes, but is not limited to, glass.

In the present embodiment, the first and second

main body portions

61 and 91 extend in the X-axis direction, the first key portion 62 is located in the middle of the first main body portion 61, and the second key portion 92 is located in the middle of the second main body portion 91. Of course, the embodiments of the present disclosure are not limited thereto, and the positions of the first and second

key portions

62 and 92 may also be set at the edges of the first and second

main body portions

61 and 91, but it is still ensured that the coordinates of the first and second

key portions

62 and 92 on the X axis are substantially consistent.

It should be noted that, in the embodiment of the present disclosure, the first bonding portion 62 and the second bonding portion 92 are arranged to keep the thermal stress generated in the X-axis direction of the acceleration detecting apparatus as zero as possible. For example, when the first support structure 6 has more than one separated first bonding portion 62 as an anchor point, the plurality of first bonding portions 62 and the structure (the substrate 101 or the first main body portion 61) bonded and connected to the first bonding portions 62 generate stress in the X-axis direction due to different thermal expansion coefficients of the bonding materials. Thus, in some preferred embodiments, the first support structure 6 has only one first key 62 connected to the substrate 101 as an anchor point, and similarly, the second support structure 9 has only one second key 92 connected to the substrate 101 as an anchor point.

The first elastic beam 3 is connected with the first main body part 61 and the isolation structure 5 respectively; the second elastic beam 4 is connected to the second main body 91 and the isolation structure 5, wherein the first elastic beam 3 and the second elastic beam 4 are symmetrically distributed on two sides of the isolation structure 5 along the X-axis direction. The elastic modulus of the first elastic beam 3 and the second elastic beam 4 in the Y-axis direction is small, allowing the isolation structure 5 to move in the Y-axis direction, while the elastic modulus in the X-axis direction is large, inhibiting the isolation structure 5 from moving in the X-axis direction. In some specific embodiments, the number of the first elastic beams 3 is plural, and the first elastic beams are symmetrically distributed on two sides of the first bonding portion 62 along the Y-axis direction, and correspondingly, the number and the distribution of the second elastic beams 4 correspond to those of the first elastic beams 3. The number of the third elastic beams 2 is two, and the third elastic beams are symmetrically distributed on two sides of the mass block 1 along the Y-axis direction and respectively connect the mass block 1 and the isolation structure 5, and of course, the specific number and distribution of the first elastic beam 3, the second elastic beam 4 and the third elastic beam 2 can also be set as required. In some specific embodiments, the first elastic beam 3, the second elastic beam 4 and the third elastic beam 2 are implemented by means of, for example, bending beams.

Fig. 4 is a schematic top view of an acceleration detecting apparatus according to a second embodiment of the present disclosure, wherein, in order to express the first supporting structure 6 and the second supporting structure 9 more clearly, the first bonding portion 62 and the second bonding portion 92 which should be hidden originally are shown in fig. 4.

As shown in fig. 4, the structure of the acceleration detecting apparatus of the present embodiment is substantially the same as that of the first embodiment, and the description thereof is omitted. The difference from the first embodiment is that the third elastic beams 2 of the present embodiment are two pairs and are symmetrically distributed on two sides of the central axis (dashed line in fig. 4) of the mass block 1 along the X-axis, and of course, the specific number of the third elastic beams 2 may also be set as required. In addition, in the present embodiment, the first main body portion 61 and the second main body portion 91 do not extend along the X-axis direction, and the orthographic projection areas of the first main body portion 61 and the first bonding portion 62 on the substrate 101 are substantially identical and at least partially overlapped; the second main body 91 and the second bonding portion 92 substantially coincide with each other in an orthographic projection area on the substrate 101 and at least partially overlap each other. Therefore, in the Y-axis direction, the position of the first elastic beam 3 corresponds to the first key portion 62, and the position of the second elastic beam 4 corresponds to the second key portion 92.

With further reference to fig. 1-4, since the X coordinates of the first and

second bonding portions

62 and 92 are substantially the same, the bonding structure will not substantially develop a tendency for relative displacement in the X direction when the temperature changes, the tendency for relative displacement occurring substantially only in the Y direction. Limited to the fixed constraint of the first and

second bonds

62, 92, thermal stresses are generated on the first and second support structures 6, 9 that cause the first and second

elastic beams

3, 4 to deform due to the different coefficients of thermal expansion between the bonding materials. If the first elastic beam 3 and the second elastic beam 4 are processed symmetrically and have the same elastic coefficient, the acting forces of the first elastic beam 3 and the second elastic beam 4 on the isolation structure 5 are offset, the isolation structure 5 is kept at the initial balance position and is still, and the thermal stress is isolated. If the elastic coefficients of the first elastic beam 3 and the second elastic beam 4 are different due to the existence of the processing error, the isolation structure 5 leaves the initial balance position under the comprehensive acting force of the first elastic beam 3 and the second elastic beam 4, and the minute displacement along the Y axis occurs to finally reach a force balance state, which also drives the mass block 1 and the first capacitor plate 7 to generate the minute displacement along the Y axis, so that the capacitor C is caused _1a 、C _1b 、C _2a 、C _2b 、C _f1a 、C _f1b 、C _f2a 、C _f2b The facing area of the first capacitor plate 7 and the second capacitor plate 8 is changed. The eight capacitors are divided into four groups (C) _1a /C _1b 、C _2a /C _2b 、C _f1a /C _f1b 、C _f2a /C _f2b ) Two capacitors in each group are connected in parallel to be used as a capacitor group, and when the first capacitor plate 7 undergoes small displacement along the Y axis, the total capacitance value of each capacitor group remains unchanged, so that the zero position of the accelerometer cannot be changed, and the effect of inhibiting stress is achieved. Wherein the respective capacitor bank can serve as a sensing capacitor or a force feedback capacitor, e.g. C _1a /C _1b And C _2a /C _2b Two capacitor groups formed respectively as detection capacitors, and C _f1a /C _f1b And C _f2a /C _f2b Two capacitor groups formed respectively are used as force feedback capacitors; and e.g. C _1a /C _1b 、C _2a /C _2b 、C _f1a /C _f1b 、C _f2a /C _f2b The four capacitor banks respectively formed are all used as detection capacitors.

The embodiment of the disclosure adds an isolation structure capable of releasing temperature stress in design, inhibits adverse effects of the temperature stress on the performance of the acceleration detection device, increases flexibility of selection of processing materials, reduces constraints on a micro-processing technology, and has great practical value.

In the above description, the technical details of patterning, etching, and the like of each layer are not described in detail. It will be appreciated by those skilled in the art that layers, regions, etc. of the desired shape may be formed by various technical means. In addition, in order to form the same structure, the person skilled in the art can also design a method which is not exactly the same as the method described above. Further, although the embodiments are described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination.

The embodiments of the present disclosure are described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The scope of the disclosure is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be devised by those skilled in the art without departing from the scope of the disclosure, and these alternatives and modifications are intended to fall within the scope of the disclosure.

Claims

1. An acceleration detection device comprising:

a substrate;

a mass located above the substrate and spaced apart from the substrate;

at least one capacitor bank connected to the mass block, the capacitance value of the capacitor bank changing with the displacement of the mass block in a first direction;

the isolation structure is elastically connected with the mass block along the first direction; and

the first supporting structure and the second supporting structure are respectively positioned at two sides of the mass block along the first direction and are respectively and elastically connected with the isolation structure along the second direction, the first direction, the second direction and the thickness direction of the substrate are mutually vertical,

the first supporting structure comprises a first bonding part and a first main body part which are connected, the second supporting structure comprises a second bonding part and a second main body part which are connected, the first supporting structure and the second supporting structure are respectively fixedly connected with the substrate through the first bonding part and the second bonding part, and a connecting line of the first bonding part and the second bonding part is relatively vertical to the first direction.

2. The acceleration detection device according to claim 1, further comprising:

two ends of the first elastic beam are respectively connected with the isolation structure and the first main body part; and

and two ends of the second elastic beam are respectively connected with the isolation structure and the second main body part.

3. The acceleration detection device of claim 2, wherein the isolation structure is ring-shaped, surrounding the mass and the capacitor bank.

4. The acceleration detection device according to claim 1, wherein the first bonding portion is different from a material of the substrate and is bonded to the substrate;

and/or the second bonding part is made of a material different from that of the substrate and is bonded and connected with the substrate.

5. The acceleration detection apparatus according to claim 1, wherein the first bonding portion is different in material from the first main body portion and is bonded to the first main body portion;

and/or the second bonding part is made of a material different from that of the second main body part and is bonded and connected with the second main body part.

6. The acceleration detection apparatus according to claim 3, wherein, in the second direction, the first elastic beam position corresponds to the first key and the second elastic beam position corresponds to the second key.

7. The acceleration detection device according to claim 3, wherein the first main body portion and the second main body portion each extend in the first direction,

the number of the first elastic beams is multiple, and the first elastic beams are distributed on two sides of the first bonding portion along the second direction, and the number of the second elastic beams is multiple, and the second elastic beams are distributed on two sides of the second bonding portion along the second direction.

8. The acceleration detection apparatus according to claim 7, wherein the first elastic beam and the second elastic beam are symmetrically distributed on both sides of the isolation structure in the first direction,

the first key part is positioned in the middle of the first main body part, and the plurality of first elastic beams are symmetrically distributed on two sides of the first key part along the second direction; the second key portion is located in the middle of the second main body portion, and the plurality of second elastic beams are symmetrically distributed on two sides of the second key portion along the second direction.

9. The acceleration detection apparatus of any one of claims 1-8, wherein each of the capacitance groups comprises:

at least one pair of first capacitor plates distributed on two sides of the mass block along the first direction; and

a second capacitor plate corresponding to each of the first capacitor plates,

wherein each of the first capacitive plates is connected to the proof mass, and each of the second capacitive plates is fixed relative to the substrate and spaced apart from the proof mass.

10. The acceleration detection apparatus according to claim 9, further comprising a plurality of third elastic beams distributed on both sides of the mass along the second direction, respectively connecting the mass and the isolation structure.

11. The acceleration detection device according to claim 10, wherein the third elastic beams are symmetrically distributed on both sides of a central axis of the mass in the first direction, the central axis being relatively parallel to the first direction.