JPH1131825A - Method for manufacturing semiconductor dynamic quantity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strictly control the thickness dimension of a beam structure body which is provided for detecting dynamic quantity. SOLUTION: On a single-crystal silicon substrate 31, a silicon oxide film 32, a polysilicon thin film 33 which is to be an interconnection pattern, a silicon nitride film 34, and a silicon oxide film 35 which is to be a sacrificial layer are film-formed. Them after an opening part 36 has been formed, polysilicon thin films 37 and 38 are film-formed on the polysilicon thin-film 38, a single- crystal silicon substrate 39 wherein an ion-implantation layer 41 is formed is pasted (f). By performing thermal treatment under the condition, the single- crystal silicon substrate 39 is released from a part of ion-implantation layer 42, to form a single-crystal silicon thin film 39a made into an SOI structure (g). Then, a trench-etching is performed with the single-crystal silicon thin-film 39a to form a groove pattern 42 for establishing a beam structure body, a fixed electrode, etc., (h). After that, a process such as the silicon oxide film 35 being removed by wet-etching is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor dynamic quantity sensor for extracting displacement of a beam structure according to the action of a dynamic quantity as a sensor output, for example, for detecting a dynamic quantity such as acceleration or yaw rate. The present invention relates to a method for manufacturing a semiconductor dynamic quantity sensor.

[0002]

2. Description of the Related Art For example, in a capacitance-type semiconductor acceleration sensor, displacement of a beam structure in accordance with the action of acceleration is provided on a movable electrode and a substrate provided integrally with the beam structure. It is configured to take out as a change in capacitance between the fixed electrodes. In such a semiconductor acceleration sensor, in order to improve the mechanical reliability of the beam structure and obtain good output characteristics, the beam structure must be made of a single crystal semiconductor having stable physical properties. It is desirable. For this reason, conventionally, SOI (Silicon On In
(sulator) It has been attempted to manufacture a semiconductor acceleration sensor having a beam structure made of single crystal silicon using a substrate forming technique and a surface micromachining technique.

More specifically, in forming an SOI substrate, a so-called bonding method is used. In this case, for example, the first single-crystal silicon substrate that eventually forms the beam structure, the fixed electrode, and the like is provided for each anchor portion for supporting the beam structure and the fixed electrode. Semiconductor film (for example, a polysilicon film),
A sacrificial layer thin film (for example, a silicon oxide film) located around a region to be an anchor portion, an etching stopper film (for example, a silicon nitride film) of the sacrificial layer thin film, and an insulator thin film (for example, a silicon oxide film) required for an SOI substrate Forming a support layer containing such a first single crystal silicon substrate;
An SOI structure is formed by performing a step of bonding a second single crystal silicon substrate serving as a base substrate to each other with the support layer interposed therebetween.

Then, the first single-crystal silicon substrate is subjected to mechanical polishing (lapping and, if necessary, polishing) to a film thickness corresponding to the thickness of the beam structure, and thereafter, to a desired film thickness and The first single crystal silicon substrate is processed into a predetermined shape by etching using photolithography technology or the like, and the first thin film for sacrificial layer is removed by wet etching. A beam structure having a movable electrode and a fixed electrode are formed on the single crystal silicon substrate.

[0005]

In the case of the above conventional configuration,
The thickness dimensions of the beam structure including the movable electrode and the fixed electrode depend on the mechanical polishing accuracy of the first single-crystal silicon substrate (the portion to be the Si region of the SOI structure) after the bonding step. However, it is difficult to sufficiently increase the film thickness controllability because the above-described mechanical polishing requires long lapping, and therefore, the target film thickness is about 10 to 20 μm. In such a case, an error (film thickness variation) of about 2 to 3 μm cannot be avoided. On the other hand, in order to keep the operating characteristics of the sensor constant, the variation in film thickness is several tens to 100 nm.
It is required to control the semiconductor acceleration sensor to less than about a degree. As a result, when the above-described manufacturing method is adopted, the output characteristics of the semiconductor acceleration sensor become unstable and the yield decreases. Comes out.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to precisely control the thickness of a beam structure provided for detecting a mechanical quantity, and to provide a sensor output. It is an object of the present invention to provide a method of manufacturing a semiconductor dynamic quantity sensor having effects such as stabilization of characteristics and improvement of yield.

[0007]

In order to achieve the above object, the manufacturing method described in claim 1 can be adopted. According to this manufacturing method, in the film forming step, the anchor portions (3a, 3b, 3) are provided on the base substrate (1, 31).
c, 3d) and a layer including the sacrificial layer thin film (35) positioned around the anchor portion, and a semiconductor substrate separately prepared from the base substrate (1, 31) in the ion implantation step. (39) is ion-implanted to a predetermined depth to form an ion-implanted layer (41, 41 ', 41 ").
1 ′, 41 ″) are distributed in parallel with the surface of the semiconductor substrate (39).

Thereafter, in a bonding step, the surface of the semiconductor substrate (39) provided with the ion-implanted layers (41, 41 ', 41 ") on the ion-implanted side and the base substrate (1, 31) And the surface on the side of the film formation side are bonded together.
Next, heat treatment is performed in a peeling step,
Along with this heat treatment, microbubbles are aggregated to form macro bubbles in a defect layer region formed by the ion-implanted layers (41, 41 ', 41 ") in the semiconductor substrate (39). As a result, an SOI structure is formed in which the semiconductor substrate (39) in the form of a thin film is laminated on the base substrate (1, 31) in a state of being insulated therefrom. .

Thereafter, in a shaping step, the semiconductor substrate (39) bonded to the base substrate (1, 31) as described above is processed into a predetermined shape, and the sacrificial layer thin film (35) is processed. Are removed by wet etching, whereby the anchor portions (3a, 3b, 3) are removed.
c, 3d), the beam structure (2,
2 ') is formed, whereby the basic structure of the semiconductor dynamic quantity sensor is completed.

According to the manufacturing method described above, the thickness dimension of the beam structure (2, 2 ') is determined according to the film thickness of the thin-film semiconductor substrate (39) separated through the separation step. For this reason, it is not necessary to perform mechanical polishing by lapping for a long time as in the conventional configuration, so that the film thickness can be controlled with high accuracy. As a result, the thickness dimension of the beam structure (2, 2 ') can be strictly controlled, and stabilization of sensor output characteristics and improvement in yield can be realized.

In this case, as in the manufacturing method according to claim 2, in the ion implantation step, the semiconductor substrate (39) is formed.
On the other hand, if the ion implantation layer (41) is formed by performing ion implantation to a depth position corresponding to the thickness dimension of the beam structure (2, 2 '), the beam structure is separated through a separation step. The thickness of the thin-film semiconductor substrate (39) depends on the ion implantation depth, and can be controlled with extremely high accuracy. Specifically, according to the manufacturing method, the thickness variation of the thin-film semiconductor substrate (39) can be reduced to the order of several nanometers, whereby the thickness of the beam structure (2, 2 ′) can be reduced. The dimension can be strictly controlled, and the stabilization of the sensor output characteristic and the improvement of the yield can be reliably realized.

According to the manufacturing method of the third and fourth aspects,
In the ion implantation step, the semiconductor substrate (39) is
Since it is only necessary to perform ion implantation to a depth position shallower than the thickness dimension of the beam structure (2, 2 '), it is not necessary to increase the ion implantation energy. As a result, a large-sized ion implantation apparatus is required. There is no danger that the manufacturing equipment will become unnecessary and increase in scale. In these manufacturing methods, the thickness dimension of the beam structure (2, 2 ') depends on the thickness of the semiconductor layer (49) formed in the growth step. Since the film thickness can be controlled with sufficiently high precision, the thickness dimension of the beam structure (2, 2 ') can be strictly controlled.

In the case where a semiconductor material is used as the material of the base substrate (1, 31) as in the manufacturing method according to claim 6, the base substrate (1, 31) and the semiconductor substrate bonded thereto are used. Since the thermal stress generated between (39) and (39) can be reduced, the occurrence of distortion in the beam structure (2, 2 ′) due to the thermal stress can be suppressed, and the deterioration of the sensor output characteristics can be prevented. Can be prevented.

Further, the displacement of the beam structure (2, 2 ') made of a semiconductor material in a state where the mechanical quantity acts is applied to the movable electrodes (7a, 7b) integrated with the beam structure (2, 2'). And fixed electrodes (8, 8 ', 9, 10, 10', 1) made of a semiconductor material.
In the case of manufacturing a capacitive semiconductor physical quantity sensor which is taken out as a sensor output corresponding to a change in the capacitance between 1) and 2), the manufacturing method described in claim 7 can be adopted.

In this manufacturing method, in the first film forming step, the wiring pattern (1) is formed on the base substrate (1, 31).
A first conductive layer thin film (33) for forming (9, 20, 21, 22) is formed in a state of being electrically insulated from the base substrate (1, 31); At
A sacrificial layer thin film (35) on the first conductive layer thin film (33)
Is formed. Further, in the opening step, the anchor portions (3a, 3b, 3c, 3) in the sacrificial layer thin film (35) are formed.
d) and fixed electrodes (8, 8 ', 9, 10, 10', 1).
A plurality of openings (36) facing the first conductive layer thin film (33) are formed in each formation region of 1), and the sacrificial layer thin film including the opening (36) is formed in a third film forming step. (3
5) The first conductive layer thin film (33)
Then, a second conductive thin film (37) electrically connected to the opening (36) is formed.

In the ion implantation step, the semiconductor substrate (39) prepared separately from the base substrate (1, 31) is ion-implanted to a predetermined depth to form an ion-implanted layer (41, 41). ′, 41 ″), and the ion-implanted layers (41, 41 ′, 41 ″) are distributed in parallel with the surface of the semiconductor substrate (39).

Thereafter, in the bonding step, the surface of the semiconductor substrate (39) provided with the ion-implanted layers (41, 41 ', 41 ") on the ion-implanted side and the third film-forming step were performed. The surface of the base substrate (1, 31) on the side of the second conductive thin film (37) is bonded, and then heat treatment is performed in a peeling step. In the defect layer region formed by the ion-implanted layers (41, 41 ', 41 ") in (1), microbubbles are aggregated to generate macro bubbles, thereby causing separation at the defect layer region as a boundary. .
As a result, the thin film semiconductor substrate (39) is laminated on the base substrate (1, 31) in a state of being insulated therefrom.
An OI structure will be formed.

Thereafter, in a shaping step, the beam structure (2, 2 ') and the fixed electrode are attached to the semiconductor substrate (39) bonded to the base substrate (1, 31) as described above. Processing such as forming a groove pattern (42) for defining (8, 8 ', 9, 10, 10', 11) and removing the sacrificial layer thin film (35) by wet etching; Thereby, the beam structure (2, 2 ') supported by the anchor portions (3a, 3b, 3c, 3d) and the fixed electrodes (8, 8',
9, 10, 10 ', and 11) are formed, whereby the basic structure of the semiconductor dynamic quantity sensor is completed.

According to the above-described manufacturing method, the beam structure (2, 2 ') and the fixed electrodes (8, 8', 9, 10, 1) are formed.
Since the thickness dimensions of 0 ′ and 11) are determined according to the film thickness of the thin-film semiconductor substrate (39) peeled off through the peeling step, the conventional structure is used for controlling the film thickness. As described above, there is no need to perform mechanical polishing by lapping for a long time, and the film thickness can be controlled with high accuracy. As a result, the thickness dimensions of the beam structure (2, 2 ') and the fixed electrodes (8, 8', 9, 10, 10 ', 11) can be strictly controlled, and the sensor output characteristics can be stabilized. And improvement of the yield can be realized.

According to a twelfth aspect of the present invention, in the ion implantation step, the semiconductor substrate (39) is
If the ion implantation layer (41) is formed by performing ion implantation to a depth position corresponding to the thickness dimension of the beam structure (2, 2 '), a thin film-like layer to be separated through a separation step is formed. Since the thickness of the semiconductor substrate (39) depends on the ion implantation depth, it can be controlled with extremely high accuracy. Specifically, according to the manufacturing method, the thickness variation of the thin-film semiconductor substrate (39) can be reduced to the order of several nanometers, whereby the beam structure (2, 2 ') and the fixed structure can be fixed. Electrodes (8, 8 ', 9, 10, 1
0′11) can be strictly controlled,
Stabilization of sensor output characteristics and improvement of yield can be reliably realized.

According to the manufacturing method of the twelfth and thirteenth aspects, in the ion implantation step, the semiconductor substrate (39) is ion-implanted to a position shallower than the thickness of the beam structure (2, 2 '). Need only be performed, it is not necessary to increase the ion implantation energy, and as a result, a large-sized ion implantation apparatus is not required, and there is no danger that the manufacturing equipment will be enlarged. In these manufacturing methods, the beam structure (2, 2 ') and the fixed electrodes (8,
The thickness dimensions of 8 ', 9, 10, 10', and 11) depend on the thickness of the semiconductor layer (49) formed in the growth step. Since the control can be performed with high accuracy, the thickness of the beam structure (2, 2 ') and the fixed electrodes (8, 8', 9, 10, 10 ', 11) can be strictly controlled.

According to a fifteenth aspect of the present invention, in the ion implantation step, the beam structure (2, 2 ') and the fixed electrode (8) are finally formed on the surface of the semiconductor substrate (39) on the ion implantation side. , 8 ', 9, 10, 10', 11), a resist layer (51) having a shape conforming to the region other than the portions to be formed is formed, and from the state of formation of the resist layer (51), the beam structure ( The ion implantation layer (41 ″) is formed by performing ion implantation to a depth position corresponding to the thickness dimension of (2, 2 ′).
Is formed, the ion implantation layer (4
1 ″) is a shape lost in a region corresponding to the resist layer (51), that is, finally, in the semiconductor substrate (39), the beam structure (2, 2 ′) and the fixed electrodes (8,
8 ', 9, 10, 10', and 11).

After performing the above-described ion implantation process,
When the bonding step and the peeling step are performed sequentially,
The portion of the semiconductor substrate (39) corresponding to the deficient region of the ion-implanted layer (41 ″) is formed on the base substrate (1,
The bonding state with the semiconductor substrate (3) is released.
The semiconductor substrate (39) bonded to the base substrate (1, 31) side has beam structures (2, 2 ') and fixed electrodes. A groove pattern equivalent to the groove pattern (42) for defining (8, 8 ', 9, 10, 10', 11) will be formed.

As in the manufacturing method according to the sixteenth aspect, in a predetermined region on the sacrificial layer thin film (35) including the opening (36), the opening (36) for the first conductive layer thin film (33) is formed. 3
6), after the execution of the third film forming step of forming the second conductive thin film (37) electrically connected and the bonding thin film (38) covering the second conductive thin film (37), finally the beam structure (2, 2 ') and fixed electrodes (8, 8', 9, 10,
It is also possible to adopt a configuration in which a step of forming a concave portion (38a) by removing the bonding thin film (38) at a portion corresponding to a region other than the portions to be 10 'and 11).

In this case, the semiconductor substrate (39) is formed in a peeling step performed after the bonding step.
Since the portion corresponding to the concave portion (38a) is not bonded to the bonding thin film (38) side, it is left on the semiconductor substrate (39) side, and accordingly, the base substrate (1) , 31) are attached to the semiconductor substrate (39), and the beam structure (2,
2 ') and fixed electrodes (8, 8', 9, 10, 10 ',
A groove pattern equivalent to the groove pattern (42) for defining 11) will be formed.

When a semiconductor material is used as the material of the base substrate (1, 31) as in the manufacturing method according to claim 19, the base substrate (1, 31) and the semiconductor substrate to be bonded thereto are used. Since the thermal stress generated between (39) and (39) can be reduced, the occurrence of distortion in the beam structure (2, 2 ′) due to the thermal stress can be suppressed, and the deterioration of the sensor output characteristics can be prevented. Can be prevented.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plurality of embodiments in which the present invention is applied to a method of manufacturing a capacitive semiconductor acceleration sensor will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 to 5 show a first embodiment of the present invention. In the first embodiment, FIG. 4 shows a plan shape of a main part of the semiconductor acceleration sensor, and FIG. 5 shows a cross-sectional shape along the line VV in FIG.

In FIGS. 4 and 5, a beam structure 2 made of single-crystal silicon (semiconductor material) doped with an impurity such as phosphorus is arranged on the upper surface of a base substrate 1. The beam structure 2 has a projection 4 projecting from the base substrate 1 side.
It is configured to be supported by the two anchor portions 3a, 3b, 3c, and 3d, and to have a predetermined gap with the base substrate 1. In addition, the anchor parts 3a, 3b, 3
c and 3d are made of a polysilicon thin film doped with an impurity such as phosphorus.

In the beam structure 2, two parallel beams 2
The beams 4 and 5 are provided between the anchors 3a and 3b and between the anchors 3c and 3d, and a rectangular mass (mass) is provided between the centers of the beams 4 and 5. A portion 6 is provided integrally with the beam portions 4 and 5 in a form orthogonal to the beam portions 4 and 5. Further, from both side surfaces of the mass portion 6, for example, four movable electrodes 7a and 7b arranged at equal intervals,
The projections are integrally formed so as to be directed in a direction parallel to the beams 4 and 5. The movable electrodes 7a and 7b are formed in a rod shape having a rectangular cross section, and the mass portion 6 is provided with a group of through-holes 6a for facilitating infiltration of an etching solution in a sacrificial layer etching step described later. ing.

On the base substrate 1, four first fixed electrodes 8 and 9 each having one end supported by anchor portions 8a and 9a are provided with the movable electrodes 7a and 7 respectively.
b are arranged in parallel with one side surface at a predetermined interval, and four second fixed electrodes 10 and 11 each having one end supported by the anchor portions 10a and 11a, Each of the movable electrodes 7a and 7b is arranged in parallel with the other side surface at a predetermined interval. The first fixed electrodes 8 and 9 and the second fixed electrodes 10 and 11 are formed in a rod shape having a rectangular cross section from single crystal silicon doped with an impurity such as phosphorus.

On the base substrate 1, there are provided a total of four electrode extraction portions 12, 13, 14, and 15 made of single crystal silicon doped with an impurity such as phosphorus.
These are anchor portions 12 protruding from the base substrate 1 side.
a, 13a, 14a, and 15a, respectively. The anchor portions 12a to 15a are made of a polysilicon thin film doped with impurities such as phosphorus.

The base substrate 1 uses single crystal silicon (semiconductor material) as its substrate material.
As shown in FIG. 5, a lower insulating thin film 1 is formed on the upper surface.
6, the conductive thin film 17 and the upper insulating thin film 18 are laminated in this order. In this case, the lower insulating thin film 16 is made of a silicon oxide film, and the upper insulating thin film 18 is made of a silicon nitride film. Further, the conductive thin film 1
Numeral 7 is a polysilicon thin film doped with impurities such as phosphorus.

The conductive thin film 17 is used to make the 4 shown in FIG.
One wiring pattern 19, 20, 21, 22 is formed, and a lower electrode 23 for canceling electrostatic force is formed.
In this case, the wiring patterns 19 and 20 are respectively the first
Wiring for the fixed electrodes 8 and 9 of FIG.
And 21 are wirings for the second fixed electrodes 10 and 11, respectively. Further, the lower electrode 23 is formed in a region facing the beam structure 2 and the fixed electrodes 8 to 11 from the lower surface side. The electrostatic force generated between the base substrate 1 and the base substrate 1 is offset.

Openings 18a (only a portion is shown in FIG. 5) are formed in the upper insulating thin film 18 at respective positions corresponding to the anchor portions 3a to 3d and 8a to 15a. Anchor portions 3a to 3d and 8a to 15a made of impurity-doped polysilicon and conductive thin film 1
7 are connected through the opening 18a.

In this case, the first fixed electrode group 8 is electrically connected to the electrode take-out section 12 through the anchor section 8a, the wiring pattern 19 and the anchor section 12a, and the first fixed electrode 9 group is connected to the anchor section 9a. , Is electrically connected to the electrode extraction portion 13 through the wiring pattern 20 and the anchor portion 13a. The second group of fixed electrodes 10 includes an anchor 10
a, the second fixed electrode 11 is electrically connected to the electrode extraction portion 14 through the wiring pattern 21 and the anchor portion 14a.
The group is electrically connected to the electrode extraction unit 15 through the anchor unit 11a, the wiring pattern 22, and the anchor unit 15a.

An electrode (bonding pad) 24 made of an aluminum thin film is provided at a position above the anchor portion 3a in the beam structure 2. In addition, the electrode extraction sections 12, 1
Electrodes (bonding pads) 25, 26, 27, and 28 made of an aluminum thin film are also provided on the upper surfaces of 3, 14, and 15, respectively.

With the above structure, a first capacitor is formed between the movable electrodes 7a and 7b of the beam structure 2 and the first fixed electrodes 8 and 9. Further, a second capacitor is formed between the movable electrodes 7 a and 7 b of the beam structure 2 and the second fixed electrodes 10 and 11. The capacitance of these first and second capacitors changes in accordance with the displacement of the movable electrodes 7a and 7b due to the acceleration acting on the beam structure 2, and such a change in the capacitance Is extracted through the electrode 24 provided on the anchor portion 3a of the beam structure 2 and the electrodes 25 to 28 provided on the electrode extraction portions 12, 13, 14, and 15, so that the acceleration can be detected.

FIGS. 1 to 3 show an example of a manufacturing process of the above-described semiconductor acceleration sensor, which will be described below. 1 to 3 are schematic cross-sectional views schematically showing the manufacturing steps in the cross section shown in FIG.

First, in a first film forming step shown in FIG. 1A, a silicon film for the lower insulating thin film 16 is formed on a single crystal silicon substrate 31 for the base substrate 1 by thermal oxidation or CVD. An oxide film 32 is formed, and a polysilicon thin film 33 (corresponding to the first conductive layer thin film in the present invention) for the conductive thin film 17 is formed on the silicon oxide film 32 by a CVD method or the like. After the film is formed, impurities are introduced by diffusion of phosphorus or the like.

In the second film forming step shown in FIG. 1B, the polysilicon thin film 33 is patterned by using photolithography, so that the wiring pattern 19 is finally formed.
To 22 and a region to be the lower electrode 23, and thereafter, a silicon nitride film 34 and a silicon oxide film 35 (corresponding to a thin film for a sacrifice layer in the present invention) for the upper insulating thin film 18 by CVD or the like. Is formed. The silicon nitride film 34 functions as an etching stopper film when the silicon oxide film 35 serving as a sacrificial layer is wet-etched.

In the opening step shown in FIG. 1C, the stacked body of the silicon oxide film 35 and the silicon nitride film 34 is
By performing an etching process through photolithography, openings 36 are formed in regions where the anchor portions 3a to 3d and 8a to 15a are formed.

In the third film forming step shown in FIG. 1D, the polysilicon thin film 37 (the second
, The impurity is introduced by phosphorus diffusion or the like, and a polysilicon thin film 38 as a bonding thin film is formed on the polysilicon thin film 37 and the silicon oxide film 34. And flattened by mechanical polishing. Thus, the polysilicon thin film 37 is electrically connected to the polysilicon thin film 33 for the conductive thin film 17 through the opening 36.
Since the diffusion of impurities from the polysilicon thin film 37 side can be expected with the subsequent heat treatment or the like, the step of introducing impurities into the polysilicon thin film 38 may be performed as necessary. good.

In the ion implantation step shown in FIG. 1E, one surface of a single crystal silicon substrate 39 (corresponding to a single crystal semiconductor substrate in the present invention) prepared separately from the single crystal silicon substrate 31 is formed. A silicon oxide film 40 functioning as a contamination protection film is previously formed to have a uniform film thickness (for example, about 0.1 μm) by thermal oxidation or a CVD method, and as shown by an arrow in FIG. By implanting hydrogen ions or rare gas ions to a predetermined depth through the silicon oxide film 40, an ion implantation layer 41 having a distribution parallel to the surface of the single crystal silicon substrate 39 is formed.

Here, the single crystal silicon substrate 39 is
This is for finally forming the beam structure 2 and the first and second fixed electrodes 8, 9 and 10, 11 and the like. In the present embodiment, the beam structure 2 and the first and second fixed electrodes 8 and 9 are used. Ion implantation is performed to a depth position corresponding to the thickness dimension of the fixed electrodes 8, 9, 10, and 11.

The dose in the above ion implantation step is hydrogen.
1 × 10 for ions¹⁶atoms / cm²Above
Or 5 × 10¹⁶atoms / cm²~ 1 × 10¹⁷toms / c
m² Set to. Also, the beam structure 2 and the first and second beams
Of the fixed electrodes 8, 9 and 10, 11
Assuming μm, hydrogen ion implantation energy is 1M
It will be set to a value exceeding eV.

In the bonding step shown in FIG. 2F, after the silicon oxide film 40 of the single crystal silicon substrate 39 is removed by, for example, chemical etching using a hydrofluoric acid aqueous solution, the surface thereof is subjected to a hydrophilic treatment and The surface of the single-crystal silicon substrate 31 on the side of the polysilicon thin film 38 is also subjected to a hydrophilic treatment, and both are adhered to each other on the hydrophilic treatment surface.

In this embodiment, the silicon oxide film 40
Is completely removed, but the silicon oxide film 40
May be left as it is, or a certain film thickness may be left by removing only the surface layer portion of the silicon oxide film 40 by a predetermined thickness.

In the peeling step shown in FIG. 2G, the single crystal silicon substrates 31 and 39 are subjected to a heat treatment so that the single crystal silicon substrate 39 is converted into a defect layer region formed by the ion implantation layer 41. As a result, an SOI structure in which a single-crystal silicon thin film 39a is stacked on a single-crystal silicon substrate 39 with a silicon oxide film 32 interposed therebetween is formed.

In this case, specifically, the ion implantation layer 41
Is formed by hydrogen ions,
Preferably, heat treatment is performed at about 400 to 600 ° C.
In response to such a heat treatment, microbubbles are aggregated in the defect layer region formed by the ion-implanted layer 41 to form macro bubbles, thereby causing separation at the defect layer region as a boundary. Become. The single crystal silicon substrate 39
After the heat treatment for peeling the single-crystal silicon thin film 39a from the silicon thin film 39a, the polysilicon thin film 38 and the single-crystal silicon thin film are further subjected to a heat treatment at a temperature higher than the heat treatment temperature (preferably about 1000 ° C. to 1200 ° C.). The bonding strength of the bonding surface with 39a is strengthened.

The single crystal silicon thin film 3 as described above
A defect layer formed due to ion implantation remains on the peeled surface 9a, and a minute step of about several nm to several tens of nm is generated (FIG. 2 (g) ignores this minute step). Therefore, in the present embodiment, the step of removing and smoothing the defect layer and the minute step formed on the single-crystal silicon thin film 39a by mechanical polishing is performed after the peeling step. I have to. However, removal and smoothing of such a defect layer and a minute step may be performed as needed.

After this, FIG. 2 (h) and FIG.
The shaping step shown in (k) is performed. That is, first, FIG.
As shown in (h), the single-crystal silicon thin film 39a having the SOI structure is subjected to trench etching using photolithography to form a beam structure 2, first fixed electrodes 8 and 9, and a second fixed electrode. 10 and 11, electrode extraction unit 1
A groove pattern 42 defining 2, 13, 14, 15 is formed. In this case, the trench etching is performed to a depth at which the groove pattern 42 reaches the silicon oxide film 35 for the sacrificial layer. Further, at this stage, impurities are introduced into the single-crystal silicon thin film 39a by phosphorus diffusion or the like in order to impart conductivity for the electrode function or the like to the single-crystal silicon thin film 39a.

Next, as shown in FIG. 3I, a silicon oxide film 43 is formed by a CVD method or the like, and the substrate surface is flattened by performing etch-back by dry etching or the like.

Further, as shown in FIG. 3 (j), an interlayer insulating film 44 is formed, a contact hole 45 is formed by photolithography and dry etching, etc., and a silicon nitride film is formed in a predetermined region on the interlayer insulating film 44. 46 is formed.

Thereafter, as shown in FIG. 3K, an aluminum thin film 47 for the aluminum electrodes 24 to 28 (see FIG. 4) is formed through a film forming step and a photolithography step, and thereafter, a passivation film 48 is formed. Is formed through a film forming step and photolithography.

Then, from the state shown in FIG. 3K, the silicon oxide films 35 and 43 are etched with a hydrofluoric acid-based etchant.
As a result, as shown in FIG. 5, the beam structure 2 having the movable electrodes 7a and 7b becomes a movable structure.
That is, the shaping process described above (see FIG. 2 (h) and FIG.
According to the execution of (i) to (k)), the anchor portions 3a to 3
The movable beam structure 2 supported by d, the first fixed electrodes 8, 9 and the second fixed electrodes 10, 11 supported by the anchor portions 8a to 11a are formed.

During the wet etching of the silicon oxide films 35 and 43 using the above-mentioned hydrofluoric acid-based etchant, the silicon nitride film 34 and the polysilicons 37 and 38 function as etching stoppers.

According to the above-described embodiment, the following effects can be obtained. That is, the beam structure 2
Is made of single-crystal silicon having stable physical properties, so that the mechanical reliability of the beam structure 2 is improved, and good sensor output characteristics can be obtained.

In this case, the thickness of the beam structure 2 is
The thickness of the single-crystal silicon thin film 39a separated from the single-crystal silicon substrate 39 through the separation step, that is, the thickness depends on the ion implantation depth in the ion implantation step. This eliminates the need for performing mechanical polishing by lapping over a long period of time as in the conventional configuration, and enables the film thickness to be controlled with high accuracy (accuracy with a film thickness variation of about several tens nm or less). As a result, the thickness dimension of the beam structure 2 can be strictly controlled, and stabilization of sensor output characteristics and improvement in yield can be reliably realized.

In this embodiment, the single-crystal silicon thin film 3
Although the mechanical polishing is performed on the peeled surface of 9a, the mechanical polishing is performed on several nm to several tens nm generated on the peeled surface.
Since it is sufficient to perform the process only to the extent that the minute step is flattened, there is no adverse effect on the film thickness accuracy.

The base substrate 1 is composed of the single crystal silicon substrate 31 having the same physical characteristics as the single crystal silicon substrate 39 constituting the beam structure 2 and the fixed electrodes 8 to 11. Then, the thermal stress generated between the substrate and the single crystal silicon substrate 39 bonded thereto can be reduced. As a result, the occurrence of distortion in the beam structure 2 or the like due to the thermal stress can be suppressed, and deterioration of the sensor output characteristics can be prevented.

(Second Embodiment) FIG. 6 schematically shows an example of a manufacturing process of a semiconductor acceleration sensor according to a second embodiment of the present invention. The differences will be mainly described.

In the second embodiment, the first film forming step (see FIG. 1A), the second film forming step (see FIG. 1B), and the opening step (FIG. c)) and the third film forming step (see FIG. 1D) are performed in the same manner as in the first embodiment.

In the ion implantation step shown in FIG. 6A, a silicon oxide film 40 functioning as a contamination protection film is formed on one surface of a single crystal silicon substrate 39 prepared separately from the single crystal silicon substrate 31 by heat. A film having a uniform thickness (for example, about 0.1 μm) is formed in advance by oxidation or CVD, and hydrogen ions or rare gas ions are passed through the silicon oxide film 40 to a predetermined depth (beam structure 2).
Depth position shallower than the thickness dimension of, for example, about several μm or less)
To form an ion implanted layer 41 '.

The dose in the ion implantation step is 1 × 10 ¹⁶ at, as in the first embodiment, in the case of hydrogen ions.
oms / cm ² or more, preferably 5 × 10 ¹⁶ atoms / cm ²
~ 1 × 10 ¹⁷ toms / cm ²
In addition, assuming that the ion implantation depth is about several nm, the implantation energy of hydrogen ions is set to about several hundred KeV.

Thereafter, a bonding step shown in FIG. 6B is performed. In this step, basically the same procedure as in the bonding step in the first embodiment (see FIG. 2F) is performed. Step, the single crystal silicon substrate 39 is bonded to the polysilicon thin film 38 on the single crystal silicon substrate 31 side.

In the peeling step shown in FIG. 6C, the single crystal silicon substrates 31 and 39 are subjected to the same heat treatment as in the first embodiment so that the single crystal silicon substrates 39 and 39 are ion-implanted. ′, And a heat treatment for strengthening the bonding strength of the bonding surface is performed, whereby the silicon oxide film 32 is formed on the single crystal silicon substrate 39 via the silicon oxide film 32. SOI in the form of laminated single crystal silicon thin film 39a '
A structure will be formed.

In the growth step shown in FIG. 6D, after the defect layer on the single-crystal silicon thin film 39a 'is removed by mechanical polishing or etching after the formation of a silicon oxide film, for example, a silane-based material is used as a raw material. By epitaxially growing a single-crystal silicon film by a CVD method or the like, a single-crystal silicon layer 49 (corresponding to a single-crystal semiconductor layer in the present invention) having a thickness corresponding to the thickness of the beam structure 2 is formed.

Thereafter, the semiconductor accelerometer is completed by executing the same shaping process (see FIGS. 2 (h) and 3 (i) to 3 (k)) as in the first embodiment.

According to the present embodiment thus configured, the single-crystal silicon layer 49 has a thickness of 10 μm in the growth process.
m, when epitaxial growth is performed
The film thickness variation can be suppressed to about several hundred nm or less. Accordingly, similarly to the first embodiment, the thickness dimension of the beam structure 2 can be controlled with sufficiently high accuracy, so that the sensor output characteristics can be stabilized and the yield can be improved.

In particular, according to the present embodiment, in the ion implantation step, it is only necessary to perform ion implantation to the single crystal silicon substrate 39 to a relatively shallow depth position, so that it is not necessary to increase the ion implantation energy. Things,
As a result, there is no need for a large-sized ion implantation apparatus, and there is no danger of increasing the scale of the manufacturing equipment.

(Third Embodiment) FIG. 7 schematically shows an example of a manufacturing process of a semiconductor acceleration sensor according to a third embodiment of the present invention. The following description focuses on the differences from the embodiment.

In the third embodiment, a first film forming step (see FIG. 1A), a second film forming step (see FIG. 1B), and an opening step (FIG. c)
3) (see FIG. 1 (d)).
This is performed in the same manner as in the embodiment. In the ion implantation step shown in FIG. 7A, the ion implantation for the single crystal silicon substrate 39 prepared separately from the single crystal silicon substrate 31 is performed by the second ion implantation.
This is performed in the same manner as in the ion implantation step (see FIG. 6A) in the embodiment.

In the growth step shown in FIG. 7B, a silicon oxide film 40 (contamination protection film) on a single crystal silicon substrate 39 is formed.
Is removed by, for example, chemical etching using an aqueous solution of hydrofluoric acid, and then single-crystal silicon is epitaxially grown on the surface of the single-crystal silicon substrate 39 to obtain a single-crystal silicon film having a thickness corresponding to the thickness of the beam structure 2. A silicon layer 50 (corresponding to a single crystal semiconductor layer in the present invention) is formed.

In this case, the single crystal silicon is grown, for example, by the molecular beam epitaxy method, and the growth temperature at this time is, for example, about 400 ° C., which is lower than the temperature at which the separation in the ion implantation layer 41 ′ occurs. It is set low.

Thereafter, the bonding step shown in FIG. 7C is performed. In this step, the procedure is basically the same as that of the bonding step in the first embodiment (see FIG. 2F). Step, the single crystal silicon substrate 39 is bonded to the polysilicon thin film 38 on the single crystal silicon substrate 31 side.

After the bonding step, the peeling step (see FIG. 2 (g)) and the shaping step (FIG. 2 (h) and FIGS. 3 (i)-(k)) are performed in the same manner as in the first embodiment. 2) to complete the semiconductor acceleration sensor.

According to the present embodiment configured as described above,
The same effects as in the second embodiment can be obtained. In particular, in the present embodiment, after performing the ion implantation step for the single crystal silicon substrate 39, the single crystal silicon layer 50 is formed by epitaxial growth of single crystal silicon using the surface thereof. Since the surface of the single crystal silicon layer 50 on the ion implantation side can be removed, a portion damaged or contaminated by the ion implantation can be removed, and as a result, the single crystal silicon layer 50 with excellent quality can be obtained. is there.

(Fourth Embodiment) FIGS. 8 and 9 show
A fourth embodiment of the present invention is shown, and the following description will focus on differences from the first embodiment. FIG.
9 schematically shows an example of a manufacturing process of the semiconductor acceleration sensor according to the fourth embodiment, and FIG. 9 is a sectional view showing a basic structure of the acceleration sensor.

In the fourth embodiment, the first film forming step (see FIG. 1A), the second film forming step (see FIG. 1B), and the opening step (FIG. c)) is performed in the same manner as in the first embodiment, but the third film forming step is performed as shown in FIG.

That is, after the opening 36 is formed in the stacked body of the silicon oxide film 35 and the silicon nitride film 34 by performing the opening step, the opening is formed in the third film forming step shown in FIG. After the polysilicon thin film 37 is embedded in the portion 36, impurities are introduced by phosphorus diffusion or the like.

In this case, in the third film forming step, a material of the same material as that of the polysilicon thin film 37 is formed on the silicon oxide film 34 and the polysilicon thin film 37 in order to flatten an embedded step of the polysilicon thin film 37. By performing flattening polishing using the silicon oxide film 34 as a stopper in a state where the polysilicon film (non-doped) is deposited,
The surface to be bonded to the single crystal silicon substrate 39 is made flat as shown in FIG.

After performing the third film forming step as described above,
The bonding step shown in FIG. 8B is performed. In this bonding step, the same ion implantation step as in the first embodiment (FIG.
After the silicon oxide film 40 of the single-crystal silicon substrate 39 that has passed through (e) is removed by chemical etching using a hydrofluoric acid aqueous solution, the surface thereof is subjected to a hydrophilic treatment, and the silicon on the single-crystal silicon substrate 31 is removed. The surface on the side of the oxide film 34 and the polysilicon thin film 37 is also subjected to a hydrophilic treatment, and both are brought into close contact with each other on the hydrophilic treatment surface and are bonded.

Next, the single crystal silicon substrate 39 is formed by the ion implantation layer 41 by performing the peeling step shown in FIG. 8C in the same manner as the peeling step in the first embodiment (see FIG. 2G). And mechanical polishing for removing and smoothing a defect layer and a minute step generated on the separated single-crystal silicon thin film 39a as necessary, thereby performing single-crystal silicon Substrate 3
An SOI structure having a form in which a single crystal silicon thin film 39a is stacked on a silicon oxide film 32 via a silicon oxide film 32 is formed.

Thereafter, the same shaping process (see FIG. 2 (h) and FIGS. 3 (i) to 3 (k)) as in the first embodiment is carried out to obtain a sectional structure as shown in FIG. Beam structure 2 '(one beam portion is denoted by reference numeral 4'), first fixed electrode (only one side is denoted by reference numeral 8 '), second fixed electrode (only one side is denoted by reference numeral) 10 ′) is completed.

According to the fourth embodiment constructed as described above, the same effects as those of the first embodiment can be obtained. In particular, according to this embodiment, the entire beam structure 2 'is formed of single crystal silicon. Therefore, the physical properties of the beam structure 2 'can be further stabilized than the beam structure 2 of the first embodiment having a two-layer structure of single crystal silicon and polysilicon, and the sensor output can be improved. This can contribute to a significant improvement in characteristics.

(Fifth Embodiment) FIG. 10 schematically shows an example of a manufacturing process of a semiconductor acceleration sensor according to a fifth embodiment of the present invention. The differences will be mainly described.

In the fifth embodiment, the first film forming step (see FIG. 1A), the second film forming step (see FIG. 1B), and the opening step (FIG. c)) and the third film forming step (see FIG. 1D) are performed in the same manner as in the first embodiment.

In the ion implantation step shown in FIG.
On one surface of a single-crystal silicon substrate 39 prepared separately from the single-crystal silicon substrate 31, a silicon oxide film 40 as a contamination protection film is previously formed to a uniform film thickness (for example, 0. A photoresist 51 having a predetermined shape is formed on the silicon oxide film 40 by patterning using photolithography (corresponding to a resist layer in the present invention).
From this state, hydrogen ions or rare gas ions are implanted through the silicon oxide film 40 to a predetermined depth (depth position corresponding to the thickness dimension of the beam structure 2) to thereby form the ion implantation layer 41. ″ Is formed.

In this case, due to the existence of the photoresist 51, the ion-implanted layer 41 ″ is
1, the shape of the deficient region (that is, the shape of the photoresist 51) is finally formed on the single crystal silicon substrate 39 by the beam structure 2,
The shapes are the same as the shapes of the regions other than the portions that become the first fixed electrodes 8 and 9, the second fixed electrodes 10 and 11, and the electrode extraction portions 12, 13, 14, and 15.

Thereafter, with the photoresist 51 removed, the bonding step shown in FIG. 10B is performed. In this step, the bonding step in the first embodiment (FIG. 2F )), The single crystal silicon substrate 39 is bonded to the polysilicon thin film 38 on the single crystal silicon substrate 31 side by basically following the same procedure.

In the peeling step shown in FIG. 10C, the single crystal silicon substrates 31 and 39 are subjected to the same heat treatment as in the first embodiment, so that the single crystal silicon substrates 39 and 39 are ion-implanted. The single-crystal silicon substrate 31 is peeled off at the defect layer region formed by
A single-crystal silicon thin film 3 is formed on a silicon oxide film 32
9a "is formed in a stacked structure. However, in this case, a portion corresponding to the defect region of the ion implantation layer 41" in the single crystal silicon substrate 39 is bonded to the polysilicon thin film 38. Is released and the state is left on the single-crystal silicon substrate 39 side. Therefore, the single-crystal silicon thin film 39a ″ includes:
The beam structure 2, the first fixed electrodes 8 and 9, the second fixed electrodes 10 and 11, and the groove patterns 42 that define the electrode extraction portions 12, 13, 14, and 15 are equivalent to the groove patterns 42 (see FIG. 2H). A groove pattern 42 'will be formed. After the heat treatment for peeling as described above, a heat treatment for strengthening the bonding strength of the bonding surface is performed, and the beam structure 2 is formed.
This is a process for introducing impurities into the single-crystal silicon thin film 39a for forming the above by phosphorus diffusion or the like.

Thereafter, as shown in FIG.
After performing a process of removing the polysilicon film 38 at a portion corresponding to the groove pattern 42 'by dry etching or the like, a shaping process is performed.

In this shaping step, the semiconductor acceleration sensor is completed by performing the same steps as those shown in FIGS. 3 (i) to 3 (k) in the first embodiment. When it is necessary to remove and smooth a defect layer and a minute step generated on the single-crystal silicon thin film 39a ″ by mechanical polishing, the mechanical polishing step is performed during the step shown in FIG. This may be performed in a state where the silicon oxide film 43 shown in FIG.

According to the present embodiment having such a configuration,
A step of performing trench etching on the single crystal silicon thin film 39a having a relatively large thickness as in the first embodiment;
In other words, there is an advantage that it is not necessary to perform a step that requires a significantly long time.

(Sixth Embodiment) FIG. 11 schematically shows an example of a manufacturing process of a semiconductor acceleration sensor according to a sixth embodiment of the present invention. The differences will be mainly described.

In the sixth embodiment, a first film forming step (see FIG. 1A), a second film forming step (see FIG. 1B), and an opening step (FIG. c)) and the third film forming step (see FIG. 1D) are performed in the same manner as in the first embodiment.

After the execution of the third film forming step, FIG.
As shown in (a), the region that becomes the groove pattern 42 (see FIG. 2 (h)), that is, the beam structure 2, the first fixed electrodes 8, 9 and the second fixed electrodes 10, 11 is finally obtained. Then, a step of forming the concave portion 38a by removing the portion of the polysilicon film 38 corresponding to the region other than the portions serving as the electrode extraction portions 12, 13, 14, 15 by dry etching.

Thereafter, a bonding step shown in FIG. 11B is performed. In this step, the single crystal silicon substrate 31 having undergone the ion implantation step (see FIG. 1E) in the first embodiment is performed. The single-crystal silicon substrate 39 is converted into a polysilicon thin film on the single-crystal silicon substrate 31 side by basically following the same procedure as the bonding step (see FIG. 2F) in the first embodiment. Attach to 38.

In the peeling step shown in FIG. 11C, the single crystal silicon substrate 31 and 39 are subjected to the same heat treatment as in the first embodiment, so that the single crystal silicon substrate 39 is ion-implanted. The single-crystal silicon thin film 39 is separated from the single-crystal silicon substrate 31 via the silicon oxide film 32
a ″ is formed to form an SOI structure having a stacked structure.
In this case, the recess 3 in the single crystal silicon substrate 39
8a, the polysilicon thin film 38
Single-crystal silicon substrate 39
Thus, the beam structure 2, the first fixed electrodes 8 and 9, the second fixed electrodes 10 and 11, and the electrode extraction portion 12 are provided on the single-crystal silicon thin film 39a ″. , 13, 14, and 15 are formed, and after the heat treatment for peeling as described above, a heat treatment for strengthening the bonding strength of the bonded surface is performed. At the same time, a process for introducing impurities into the single crystal silicon thin film 39a for forming the beam structure 2 and the like by phosphorus diffusion or the like is performed.

Thereafter, the semiconductor acceleration sensor is completed by performing the same steps as the shaping steps (FIGS. 3I to 3K) in the first embodiment. When it is necessary to remove and smooth a defect layer and a minute step generated on the single-crystal silicon thin film 39a ″ by mechanical polishing, the mechanical polishing step is performed during the step shown in FIG. This may be performed in a state where the silicon oxide film 43 shown in FIG.

According to the present embodiment having such a structure, the step of performing trench etching on the single crystal silicon thin film 39a having a relatively large thickness, that is, the step of significantly increasing the required time is not required. There is.

(Seventh Embodiment) FIG. 12 schematically shows an example of a manufacturing process of a semiconductor acceleration sensor according to a seventh embodiment of the present invention. The differences will be mainly described.

In the first film forming step shown in FIGS. 12A and 12B, a single crystal silicon substrate 31 for the base substrate 1 is formed.
A silicon oxide film 32 for the lower insulating thin film 16 is formed thereon by thermal oxidation or a CVD method, and the regions that will eventually become the wiring patterns 19 to 22 and the lower electrode 23 are removed by dry etching. Thereby, a step portion 32a thinner than other portions is formed (FIG. 12A).
reference). Next, a polysilicon thin film 33 for the conductive thin film 17 is formed on the silicon oxide film 32 by a CVD method or the like.
Is formed, the upper surface is flattened by performing mechanical polishing using the silicon oxide film 32 as a stopper, and then an impurity is introduced into the polysilicon film 33 by phosphorus diffusion or the like (see FIG. 12B).

In the second film forming step shown in FIG. 12C, a C film is formed on the silicon oxide film 32 and the polysilicon oxide film 33.
A silicon nitride film 34 and a silicon oxide film 35 for the upper insulating thin film 18 are formed by a VD method or the like.

In the opening step shown in FIG. 12D, the stacked body of the silicon oxide film 35 and the silicon nitride film 34 is subjected to an etching process through photolithography, so that the anchor portions 3a to 3d and 8a to 15a The opening 36 is formed in the formation region of. The third shown in FIG.
In the film forming process, the polysilicon thin film 37 is
Then, an impurity is introduced by phosphorus diffusion or the like, and a polysilicon thin film 38 for bonding is formed on the polysilicon thin film 37 and the silicon oxide film 34, and is planarized by mechanical polishing. Thus, the polysilicon thin film 37 is electrically connected to the polysilicon thin film 33 for the conductive thin film 17 through the opening 36.

Thereafter, the same ion implantation step as in the first embodiment (see FIG. 1E) and the bonding step (FIG. 2)
(F)), a peeling step (see FIG. 2 (g)), and a shaping step (see FIG. 2 (h) and FIGS. 3 (i) to (k)) to complete the semiconductor acceleration sensor.

(Other Embodiments) The present invention is not limited to the above-described embodiment, but can be modified or expanded as follows. The semiconductor material of the semiconductor substrate and the semiconductor layer formed in the growth step is not limited to single-crystal silicon as described in the embodiment, and any semiconductor material mainly containing a group 4 element, such as Ge A polycrystalline semiconductor substrate made of (germanium), SiC (silicon carbide), SiGe (silicon germanium), or the like, a semiconductor substrate on which a polycrystalline film is grown, or a substrate such as diamond can be used.

The base substrate 1 is not limited to the single crystal silicon substrate 31, but may be another semiconductor substrate or a ceramic substrate or a glass substrate having an insulating property. In this case, if the base substrate itself has insulating properties, it is not necessary to perform a step of separately forming an insulating thin film (the silicon oxide film 32 in the embodiment) on the base substrate.

In the second embodiment, the single-crystal silicon layer 49 is formed by epitaxial growth on the surface of the single-crystal silicon substrate 39 (single-crystal silicon thin film 39 a ′) after the separation step. A single crystal silicon layer may be formed by forming an amorphous layer on the surface of the substrate and subjecting the amorphous layer to solid phase growth by heat treatment.

In the third embodiment, the single crystal silicon layer 50 is formed by epitaxial growth on the surface of the single crystal silicon substrate 39 before the execution of the bonding step.
A bonding step and a peeling step are sequentially performed in a state where an amorphous layer is formed on the surface of the single crystal silicon substrate 39, and thereafter, a heat treatment is performed, so that the amorphous state in a state bonded to the single crystal silicon substrate 31 side is obtained. A structure in which a single crystal silicon layer is formed by solid phase growth of a layer may be employed.

Although the embodiment applied to the method of manufacturing the capacitive type semiconductor acceleration sensor has been described, the invention can also be applied to a sensor for detecting a physical quantity such as yaw rate, vibration, angular velocity, and the like. Further, the acceleration sensor having the movable electrode in the beam structure has been described. However, the present invention can be applied to a piezoresistive semiconductor acceleration sensor having a strain gauge resistance in the beam structure.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a manufacturing process according to a first embodiment of the present invention;

FIG. 2 is a sectional view schematically showing the same manufacturing process.

FIG. 3 is a cross-sectional view schematically showing the same manufacturing process.

FIG. 4 is a plan view of a main part of the semiconductor acceleration sensor.

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

FIG. 6 is a sectional view schematically showing a manufacturing process according to a second embodiment of the present invention.

FIG. 7 is a sectional view schematically showing a manufacturing process according to a third embodiment of the present invention.

FIG. 8 is a sectional view schematically showing a manufacturing process according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view showing a basic structure of a semiconductor acceleration sensor.

FIG. 10 is a sectional view schematically showing a manufacturing process according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view schematically showing a manufacturing process according to a sixth embodiment of the present invention.

FIG. 12 is a sectional view schematically showing a manufacturing process according to a seventh embodiment of the present invention.

[Explanation of symbols]

1 is a base substrate, 2 and 2 'are beam structures, 3a to 3d are anchor portions, 7a and 7b are movable electrodes, 8, 8' and 9 are first electrodes.
Fixed electrodes, 8a, 9a are anchor portions, 10, 10 ',
11 is a first fixed electrode, 10a and 11a are anchor portions,
16 is a lower insulating thin film, 17 is a conductive thin film, 18 is an upper insulating thin film, 19 to 22 are wiring patterns, 31 is a single crystal silicon substrate (base substrate), 32 is a silicon oxide film (insulating thin film). , 32a are steps, 33 is a polysilicon thin film (thin film for the first conductive layer), 34 is a silicon nitride film (etching stopper film), 35 is a silicon oxide film (thin film for a sacrificial layer), 36 is an opening, 37 Is a polysilicon thin film (thin film for the second conductive layer), 38a is a concave portion, 39 is a single crystal silicon substrate (semiconductor substrate), 39a, 39a ', 39
a ″ is a single crystal silicon thin film, 41, 41 ′ and 41 ″ are ion implantation layers, 42 is a groove pattern, 49 and 50 are single crystal silicon layers (semiconductor layers), and 51 is a photoresist (resist layer).

Claims (22)

[Claims] 1. A base substrate (1, 31), and anchor portions (3a, 3b, 3c, 3b, 3c, 3d) on the base substrate (1, 31) in a state electrically insulated from the base substrate.
3d), and a beam structure (2, 2 ′) made of a semiconductor material that is displaced in response to the action of the mechanical quantity. '), Wherein the displacement of the semiconductor dynamic quantity sensor is taken out as a sensor output, wherein the anchor portion (3) is provided on the base substrate (1, 31).
a, 3b, 3c, 3d) and a film forming step of forming a layer including the sacrificial layer thin film (35) located around the anchor portion; a semiconductor prepared separately from the base substrate (1, 31) An ion implantation step of performing ion implantation to the substrate (39) to a predetermined depth to form an ion implantation layer (41, 41 ′, 41 ″); and an ion implantation side of the semiconductor substrate (39) having undergone the ion implantation step. Surface and the base substrate (1,
31) a bonding step of bonding the film-forming side to the film-forming side; and performing heat treatment to form the semiconductor substrate (39) in the defect layer region formed by the ion-implanted layers (41, 41 ′, 41 ″). The semiconductor substrate (39) bonded to the base substrate (1, 31) side is processed into a predetermined shape, and the sacrificial layer thin film (35) is removed by wet etching. The anchor portions (3a, 3b, 3c,
3d) forming a beam structure (2, 2 ') supported by 3d). 2. In the ion implantation step, an ion implantation is performed on the semiconductor substrate (39) to a depth position corresponding to a thickness dimension of the beam structure (2, 2 ′). The method according to claim 1, wherein (41) is formed. 3. In the ion implantation step, the semiconductor substrate (39) is ion-implanted to a depth position shallower than a thickness dimension of the beam structure (2, 2 ′) to thereby form an ion implantation layer ( 41 ′), and after the peeling step is performed, the base substrate (1,
31) The semiconductor substrate (3) bonded to the side
A growth step of forming a semiconductor layer (49) having a thickness corresponding to the thickness dimension of the beam structure (2, 2 ') by growing a semiconductor on the surface of the peeled portion of 9); 2. The method according to claim 1, wherein the shaping step is performed later. 4. In the ion implantation step, ion implantation is performed on the semiconductor substrate (39) to a depth position shallower than a thickness dimension of the beam structure (2, 2 ′), thereby forming an ion implantation layer ( 41 ′), and before the bonding step is performed, the semiconductor substrate (39) has a temperature on the ion-implanted side of the semiconductor substrate (39) at a temperature at which delamination of the semiconductor in the ion-implanted layer (41 ′) occurs. Performing a growth step of forming a semiconductor layer (50) having a thickness corresponding to the thickness dimension of the beam structure (2, 2 ') by growing at a lower temperature; 2. The method according to claim 1, wherein a peeling step and a shaping step are performed. 5. The method according to claim 3, wherein in the growing step, the semiconductor layers (49, 50) are formed by epitaxial growth. 6. A semiconductor material is used as a material of said base substrate (1, 31). In said film forming step, after forming an insulating thin film (32) on said base substrate (1, 31), The sacrificial layer thin film (3) is formed on the insulator thin film (32).
The method for manufacturing a semiconductor physical quantity sensor according to any one of claims 1 to 5, wherein a layer containing (5) is formed. 7. A base substrate (1, 31), and anchor portions (3a, 3b, 3c, 3b, 3c, 3b) on the base substrate (1, 31) in a state of being electrically insulated from the base substrate.
3d), a beam structure (2, 2 ') made of a semiconductor material and integrally having movable electrodes (7a, 7b), and electrically connected to the base substrate (1, 31) on the base substrate (1, 31). The movable electrodes (7a, 7a) are formed in an insulated state.
b) and fixed electrodes (8, 8 ', 9, 10, 10', 11) made of a semiconductor material opposed to each other with a predetermined distance therebetween, and the beam structure in a state where a mechanical quantity acts thereon A change in capacitance between the movable electrode (7a, 7b) and the fixed electrode (8, 8 ', 9, 10, 10', 11) accompanying the displacement of (2, 2 ') is taken out as a sensor output. In the method for manufacturing a capacitive semiconductor dynamic quantity sensor, a wiring pattern (1) is formed on the base substrate (1, 31).
A first film forming step of forming a first conductive layer thin film (33) for forming (9, 20, 21, 22) in a state of being electrically insulated from the base substrate (1, 31); The thin film for a sacrificial layer (3) is formed on the first thin film for a conductive layer (33).
5) a second film forming step, wherein the anchor portion (3) in the sacrificial layer thin film (35) is formed.
a, 3b, 3c, 3d) and fixed electrodes (8, 8 ', 9,
An opening step of forming a plurality of openings (36) facing the first conductive layer thin film (33) in respective formation regions of (10, 10 ', 11), for the sacrificial layer including the openings (36); A second conductive thin film (37) electrically connected to the first conductive layer thin film (33) through the opening (36) is formed in a predetermined region on the thin film (35). A third film forming step, in which a semiconductor substrate (39) prepared separately from the base substrate (1, 31) is ion-implanted to a predetermined depth to form ion-implanted layers (41, 41 ', 41 "). An ion implantation step to be performed; an ion implantation side surface of the semiconductor substrate (39) having undergone the ion implantation step; and a second conductive thin film (37) side of the base substrate (1, 31) having undergone the third film formation step. Bonding process, heat treatment And a peeling step of peeling the semiconductor substrate (39) at a defect layer region formed by the ion-implanted layers (41, 41 ', 41 "), in a state of being bonded to the base substrate (1, 31) side. To the semiconductor substrate (39), the beam structure (2,
2 ') and fixed electrodes (8, 8', 9, 10, 10 ',
Processing such as forming a groove pattern (42) defining 11) is performed, and the sacrificial layer thin film (35) is removed by wet etching to be supported by the anchor portions (3a, 3b, 3c, 3d). Beam structure (2, 2 ') and the fixed electrodes (8, 8',
9. A method of manufacturing a semiconductor physical quantity sensor, comprising performing a shaping step of forming 9, 10, 10 ', and 11). 8. In the third film forming step, only the region corresponding to the opening (36) in the thin film for sacrificial layer (35) is electrically connected to the first thin film for conductive layer (33). The method according to claim 7, wherein the second conductive thin film (37) is formed in a separated state. 9. In the third film forming step, after the second conductive layer thin film (37) is embedded in the opening (36) formed in the opening step, the second conductive layer thin film is formed. The same material as the thin film (37) is deposited, and in this state, the first material is deposited.
9. The method for manufacturing a semiconductor dynamic quantity sensor according to claim 8, wherein a flattening polishing for flattening a step of burying the thin film for a conductive layer (37) is performed. 10. An etching stopper film (3) interposed between the first conductive layer thin film (33) and the sacrificial layer thin film (35) before performing the second film forming step.
The method of manufacturing a semiconductor dynamic quantity sensor according to any one of claims 7 to 9, wherein the step (4) is performed. 11. In the ion implantation step, the semiconductor substrate (39) is ion-implanted to a depth corresponding to a thickness dimension of the beam structure (2, 2 ′). The method according to any one of claims 7 to 10, wherein (41) is formed. 12. In the ion implantation step, the semiconductor substrate (39) is ion-implanted to a depth position shallower than a thickness dimension of the beam structure (2, 2 ′) to thereby form an ion implantation layer ( 41 ′), and after the peeling step is performed, the base substrate (1,
31) The semiconductor substrate (3) bonded to the side
A growth step of forming a semiconductor layer (49) having a thickness corresponding to the thickness dimension of the beam structure (2, 2 ') by growing a semiconductor on the surface of the peeled portion of 9); The method according to any one of claims 7 to 10, wherein the shaping step is performed later. 13. In the ion implantation step, the semiconductor substrate (39) is ion-implanted to a depth position shallower than a thickness dimension of the beam structure (2, 2 ′), thereby forming an ion-implanted layer (39). 41 ′), and before the bonding step is performed, the semiconductor substrate (39) has a temperature on the ion-implanted side of the semiconductor substrate (39) at a temperature at which separation of the semiconductor in the ion-implanted layer (41 ′) occurs. Performing a growth step of forming a semiconductor layer (50) having a thickness corresponding to the thickness dimension of the beam structure (2, 2 ') by growing at a lower temperature; The method for manufacturing a semiconductor physical quantity sensor according to claim 7, wherein a peeling step and a shaping step are performed. 14. The method according to claim 12, wherein in the growing step, the semiconductor layers (49, 50) are formed by epitaxial growth. 15. In the ion implantation step, finally, a beam structure (2, 2 ′) and fixed electrodes (8, 8 ′, 9, 10) are formed on a surface of the semiconductor substrate (39) on an ion implantation side. ,
A resist layer (51) having a shape corresponding to a region other than the portions to be 10 ', 11) is formed, and from this state, a depth position corresponding to the thickness dimension of the beam structure (2, 2') is formed. Ion implantation layer (41 ″) by performing ion implantation up to
The method for manufacturing a semiconductor dynamic quantity sensor according to claim 7, wherein: 16. In the third film forming step, an opening is formed in a predetermined region on the sacrificial layer thin film (35) including the opening (36) with respect to the first conductive layer thin film (33). The second conductive thin film (37) electrically connected through the portion (36) and the bonding thin film (3) covering the second conductive thin film (37).
8), and after the execution of the third film forming step, finally, the beam structure (2, 2) is formed.
2 ') and fixed electrodes (8, 8', 9, 10, 10 ', 1).
The method according to claim 1, wherein the bonding step is performed after performing a step of forming a concave portion (38a) by removing the bonding thin film (38) in a part corresponding to a region other than the part to be 1). A method for manufacturing a semiconductor dynamic quantity sensor according to any one of 7 to 15. 17. In the first film forming step, an insulating thin film (32) is formed on a base substrate (1, 31), and an insulating thin film (32) for the wiring patterns (19, 20, 21, 22) is formed. By removing the region, a step portion (32a) thinner than other portions is formed, and the first conductive layer thin film (33) is formed on the step portion (32a). 17. The method of manufacturing a semiconductor physical quantity sensor according to claim 7, wherein: 18. Before or after execution of the shaping step, impurities are added to at least a semiconductor portion constituting the movable electrodes (7a, 7b) and the fixed electrodes (8, 8 ', 9, 10, 10', 11). 8. The method of claim 7, wherein
18. The method for manufacturing a semiconductor dynamic quantity sensor according to any one of claims 17 to 17. 19. A semiconductor material is used as a material of the base substrate (1, 31), and in the first film forming step, after forming an insulator thin film (32) on the base substrate (1, 31). The thin film for a first conductive layer (33) is formed on the insulating thin film (32).
19. The method for manufacturing a semiconductor physical quantity sensor according to any one of claims 18 to 18. 20. The semiconductor dynamic quantity sensor according to claim 7, wherein said first and second conductive thin films are formed by introducing impurities into polycrystalline silicon. Production method. 21. The method according to claim 1, wherein the semiconductor substrate is a single-crystal semiconductor substrate. 22. The method according to claim 3, wherein the semiconductor layer is a single-crystal semiconductor layer.