JPH07231103A - Semiconductor dynamic-quantity sensor apparatus and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide the semiconductor dynamic-quantity sensor apparatus having a structure which can decrease the residual stress at a beam-shaped part without heat treatment for a long time at high temperature and the manufacturing method for forming the apparatus at low heat-treating temperature matching an IC process. CONSTITUTION:When polysilicon is formed on the main surface of a P-type silicon substrate 17, the P-type silicon substrate 17 is held at 575 deg.C or lower (the specified temperature where tensile stress is generated in the polysilicon). Thereafter, a beam-shaped movable electrode 24 is formed by partially etching out the formed polysilicon. Thereafter, heat treatment is performed for the P-type silicon substrate 17 at 950 deg.C (the temperature where the tensile stress generated in the polysilicon in film formation is alleviated until the temperature becomes substantially zero, and the temperature where the diffusion of impurities introduced into the P-type polysilicon substrate 17 is substantially suppressed). In this way, the semiconductor acceleration sensor having the beam-shaped part and the movable part comprising the polysilicon having the less residual stress, whose crystal-particle diameter is 100 nm or less, is obtained.

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 device having a displaceable movable part, and more particularly to a semiconductor dynamic quantity sensor device suitable for vehicle body control, engine control, airbag control, etc. of a moving body such as an automobile. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, as a mechanical quantity sensor device having a thin film beam structure for detecting an external force (acceleration sensor etc.), a piezoelectric type utilizing a piezoelectric effect, a magnetic type utilizing a differential transformer,
Alternatively, a semiconductor type such as a semiconductor strain gauge type, a capacitance type, or a MISFET type, which makes full use of silicon microfabrication technology, is widely known. Among them, the semiconductor type is regarded as the most promising as a method that can detect a low acceleration level and a low frequency level with high accuracy and is suitable for mass production at a low cost. In the case of the semiconductor type, it is inevitable that the movable part is made thin due to the demand for miniaturization.

As a conventional example of a semiconductor dynamic quantity sensor device having such a thin film beam structure, there is one shown in SAE910496. FIG. 20 is a diagram showing the semiconductor mechanical quantity sensor device. In this technique, a movable electrode is formed of polycrystalline silicon on a silicon substrate by using a surface micromachining technique, and the acceleration is detected by a change in capacitance between the movable electrode and the fixed electrode due to the acceleration.

[0004]

However, as shown in FIG.
The structure having the doubly supported beam-like portion as shown in (1) has a problem that the structure is deformed from the originally designed shape due to residual stress (particularly compressive stress) at the time of manufacturing. The residual stress of polycrystalline silicon can be reduced to some extent by heat treatment (annealing) at high temperature for a long time.
There is a problem that it is not compatible with the C process.
That is, when it is attempted to form another control circuit (a detection circuit of a semiconductor dynamical amount sensor device, etc.) including the semiconductor dynamical amount sensor device and a MOSFET etc. on the same substrate for downsizing, etc. There is a problem that the impurities introduced into the substrate as the MOSFET are diffused by heat and the characteristics are changed. In addition, it is not practical because it wastes a lot of time and also reduces productivity.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a semiconductor dynamic quantity sensor device having a structure capable of reducing the residual stress of a beam-like portion without performing a heat treatment at a high temperature for a long time, and at a low heat treatment temperature compatible with an IC process. It is to provide a manufacturing method for forming.

[0006]

In order to achieve the above object, the semiconductor dynamical amount sensor device according to the invention of claim 1 has a first step of forming polycrystalline silicon on a main surface of a substrate. And a second step of partially removing the polycrystalline silicon by etching to form a beam-shaped movable portion,
A semiconductor dynamical quantity sensor device for detecting the external force based on the displacement of the movable part due to the action of the external force, wherein the semiconductor dynamical quantity sensor device detects an external force and outputs a signal. M for processing this external force detection signal
A substrate is manufactured by forming a control circuit including an OSFET on at least the same substrate surface, and the substrate is provided at a predetermined temperature that causes tensile stress in the polycrystalline silicon during the first step. The polycrystalline silicon is formed while maintaining the above condition, and after the second step, the tensile stress generated in the polycrystalline silicon is further relaxed until it becomes substantially zero, and the impurities introduced into the substrate as the MOSFET are removed. It is characterized in that a third step of heat-treating the substrate is carried out at a temperature at which diffusion is substantially suppressed.

According to a second aspect of the present invention, in the first aspect, the set temperature of the substrate in the first step is set to 575 ° C. or lower, and according to the third aspect, in the first aspect, the Set the temperature of the substrate in the first step to 57
The heat treatment temperature for the substrate in the third step is 950 ° C., and according to claim 4,
In the various members forming the external force detecting unit and the control circuit, a member having a common superposition positional relationship with at least the substrate main surface and made of the same material is the substrate main surface. It is selectively formed in the same process as above.

Further, in order to achieve the above object, the method for manufacturing a semiconductor dynamical amount sensor device according to claim 5 of the present invention comprises a first step of forming an insulating film on the main surface of the substrate, and the insulating step. The second step of forming polycrystalline silicon on the film, the third step of partially etching away the polycrystalline silicon to form a beam-shaped portion, and the insulating film below the beam-shaped portion A fourth step of forming a beam structure by etching as a sacrificial layer, wherein the beam structure has a movable portion that is freely displaced by the action of an external force, and based on the displacement of the movable portion, A method for manufacturing a semiconductor dynamical amount sensor device for detecting an external force, wherein the semiconductor dynamical amount sensor device includes a control circuit including the beam structure and a MOSFET that processes an external force detection signal from the beam structure. At least the same It is manufactured by being formed on a main surface of a substrate, and the polycrystalline silicon is formed while maintaining the substrate at a predetermined temperature that causes tensile stress in the polycrystalline silicon in the second step. The tensile stress generated in the polycrystalline silicon by the subsequent fourth step is relaxed to substantially zero and the MOSFET is
As a fifth aspect, the fifth step of performing heat treatment on the substrate is performed at a temperature at which diffusion of impurities introduced into the substrate is substantially suppressed.

According to a sixth aspect of the invention, in the fifth aspect, the set temperature of the substrate in the second step is 575 ° C. or lower, and the seventh aspect is the fifth aspect. Set the temperature of the substrate in the second step to 57
The heat treatment temperature for the substrate in the fifth step is set to 0 ° C., and the heat treatment temperature to the substrate is set to 950 ° C. According to claim 8, in claim 5, various types constituting the beam structure and the control circuit are provided. Among the members, a member having the same overlapping positional relationship with the main surface of the substrate and made of the same material is formed on the main surface of the substrate in at least the same step.

According to a ninth aspect of the present invention, the movable portion and the beam structure of the semiconductor dynamical amount sensor device manufactured in the present invention are made of polycrystalline silicon and have a crystal grain size of 100.
It is characterized in that it is less than or equal to nm. In the present invention, the external force acting on the movable portion refers to any force capable of displacing the movable portion such as various pressures, electrostatic force, electromagnetic force, etc. in addition to the acceleration shown in the embodiment.

[0011]

[Operation and effects of the invention] Claim 1 constructed as described above.
According to the invention described above, when the polycrystalline silicon is formed on the main surface of the substrate (first step), the polycrystalline silicon is formed while the substrate is kept at a predetermined temperature that causes tensile stress in the polycrystalline silicon. After the polycrystalline silicon is formed and the beam-shaped movable portion is formed by partially removing the polycrystalline silicon by etching (second step), the tensile stress generated in the polycrystalline silicon becomes substantially zero. It will be alleviated
The substrate is heat-treated at a temperature at which diffusion of impurities introduced into the substrate as a MOSFET is substantially suppressed (third step). As a result, it is possible to obtain a semiconductor dynamic quantity sensor device having a structure capable of reducing the residual stress of the beam-shaped portion without performing a heat treatment at a high temperature for a long time, and the semiconductor dynamic quantity sensor device at a low heat treatment temperature compatible with the IC process. Can be manufactured.

At this time, the substrate set temperature in the first step is set to 575 ° C. or lower, or the substrate set temperature in the first step is set to 570 ° C. to form a polysilicon film, and the third film is formed. The heat treatment temperature for the substrate in the step is preferably 950 ° C., which is compatible with the IC process. By the manufacturing method as described above, the crystal grain size of the movable portion and the beam structure made of polycrystalline silicon can be 100 nm or less, and the residual stress of the beam-shaped portion can be substantially zero.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram showing a plan view of a semiconductor dynamic quantity sensor device which is manufactured by a semiconductor process and has a doubly supported beam-like portion which is displaced by the action of acceleration, for example. 2 shows a cross section taken along the line AA of FIG. 1, and FIG.
3 shows a cross section taken along line BB of FIG.

An insulating film 2 is formed on a P-type silicon substrate 1, and the insulating film 2 is made of SiO ₂ , Si ₃ N ₄ or the like.
Further, a rectangular region without the insulating film 2, that is, a void portion 3 is formed on the P-type silicon substrate 1 (see FIG. 1). On the insulating film 2, a movable electrode 4 (movable portion) having a double-supported beam structure is arranged so as to bridge the void 3.
The movable electrode 4 linearly extends in a strip shape and is made of polysilicon (polycrystalline silicon) having a crystal grain size of about 50 nm.
The insulating film 2 insulates the P-type silicon substrate 1 and the movable electrode 4 from each other.

The gap 3 below the movable electrode 4
Is formed by etching a part of the insulating film 2 as a sacrificial layer. When the sacrifice layer is etched, an etching solution that does not etch the movable electrode 4 but etches the insulating film 2 that is the sacrifice layer is used as the etching solution. An interlayer insulating film 5 is arranged on the insulating film 2, and an aluminum wiring 6 for electrically connecting to the movable electrode 4 via a contact hole 7 is arranged thereon.

In FIG. 3, fixed electrodes 8 and 9 made of impurity diffusion layers are formed on both sides of the movable electrode 4 on the P-type silicon substrate 1, and the fixed electrodes 8 and 9 are ion-implanted into the P-type silicon substrate 1. It is formed by introducing N-type impurities. Further, as shown in FIG. 1, wirings 10 and 11 made of an impurity diffusion layer are formed in the P-type silicon substrate 1, and the wirings 10 and 11 introduce N-type impurities into the P-type silicon substrate 1 by ion implantation or the like. It is formed by The fixed electrode 8 and the wiring 10 are electrically connected to each other, and the fixed electrode 9 and the wiring 11 are electrically connected to each other.

Further, the wiring 10 has a contact hole 12
It is electrically connected to the aluminum wiring 13 via.
Further, the wiring 11 is electrically connected to the aluminum wiring 15 through the contact hole 14. The aluminum wirings 13, 15 and 6 are connected to an external electronic circuit.
Further, as shown in FIG. 3, an inversion layer 16 is formed between the fixed electrodes 8 and 9 on the P-type silicon substrate 1, and the inversion layer 16 applies a voltage to the movable electrode (double-supported beam) 4. It was caused by.

Next, the manufacturing process of the semiconductor dynamical quantity sensor device thus constructed will be described with reference to FIGS.
Here, a sensor is shown on the left side of the drawing, and a process of a transistor (IC process) necessary for a processing circuit is shown on the right side. As shown in FIG. 4, a P-type silicon substrate 17 is prepared, a photolithography process is performed, and an N-type diffusion layer 1 serving as a source / drain wiring portion of a sensor or a transistor is formed by ion implantation or the like.
8, 19, 20, 21 are formed.

Then, as shown in FIG. 5, an insulating film 22, a part of which serves as a sacrifice layer, is formed in the sensor manufacturing portion. still,
At this time, the insulating film 22 may be formed over the entire substrate, and then the insulating film over the transistor formation portion may be removed. Further, as shown in FIG. 6, a gate oxide film 23 is formed on the transistor manufacturing portion by gate oxidation.

Next, while keeping the P-type silicon substrate 17 at 570 ° C. constant, polysilicon is deposited by LPCVD or the like. At this time, SiH ₄ was 80 sccm, and the deposition pressure was 167 mtoor. Then, as shown in FIG.
After the photolithography process, the movable electrode 24 of the sensor and the gate electrode 25 of the transistor are patterned by dry etching or the like.

After that, the P-type silicon substrate 17 is annealed at a temperature of 950 ° C. for 3 hours in an inert gas atmosphere. FIG. 15 is a graph showing the relationship between the annealing temperature and the residual stress. Substrate temperature 570 as shown
If the polysilicon film is formed at a temperature of 950 ° C., the residual stress in the polysilicon can be reduced to almost 0 at a heat treatment temperature as low as 950 ° C.
At H ₄ : 80 sccm, deposition pressure: 184 mtoor), it can be seen that the residual stress cannot be reduced so much at the heat treatment temperature (950 ° C.) that does not affect the IC process, and even if the high temperature heat treatment is performed, the residual stress cannot be brought close to 0. . Although there is a slight difference in the deposition pressure depending on the manufacturing conditions, the difference in the deposition pressure does not pose a problem in this process.

FIG. 16 is a TEM photograph of the region C in FIG. 7 observed after the polysilicon film is formed at 570 ° C., and FIG. 17 is a TEM photograph after annealing it at 950 ° C. for 3 hours. Is. Further, FIG. 18 is a TEM photograph after forming a polysilicon film at 580 ° C., and FIG.
3 is a TEM photograph after annealing at 150 ° C. for 3 hours. By forming a polysilicon film at a substrate temperature of 570 ° C. as described above, the crystal grain size can be reduced to 50 nm or less at a heat treatment temperature as low as 950 ° C., and the residual stress in the polysilicon is almost 0 (zero). However, the residual stress of the polysilicon film formed at a substrate temperature of 580 ° C. cannot be reduced to almost 0 even by heat treatment at a high temperature of 1150 ° C. This is because the substrate temperature is set to 570 ° C. and polysilicon is deposited to set the crystal grain size to 100 nm or less (about 50 nm in this embodiment). It is considered that this is because the volume of the (gap) becomes large and the expansion and contraction of the polysilicon due to the heat treatment can be eased easily.

As described above, it is desirable that the residual stress of the polysilicon used for the beam-shaped portion be close to 0, but in the strong sense, it is preferable that the tensile stress remains rather than the compressive stress remains. This is because in the case of compressive stress, buckling deformation occurs when the length of the structure increases, whereas in the case of tensile stress, the structure does not buckle and deform. Therefore, 570 ° C., which gives tensile stress at a heat treatment temperature of 950 ° C. or lower, is more preferable than 580 ° C., where compressive stress remains even after heat treatment.

FIG. 14 shows what kind of stress is generated during the film formation when the film formation temperature of polysilicon is variously changed. According to the figure, the stress generated at the film forming temperatures of 570 ° C. and 575 ° C. is tensile stress,
It can be seen that the stress generated at 590 ° C, 600 ° C, and 610 ° C is compressive stress. In addition, the stress at 560 ° C is tensile stress, which is approximately 200MP
It is known to be between a and 300 MPa. In the figure, the stress at 560 ° C. is estimated, and the estimated value is indicated by a broken line. Further, the stress generated between the film forming temperatures of 575 ° C. and 580 ° C. is unstable at the boundary of 0 (zero), and in this range, compressive stress may occur during film forming. There is a nature.

Therefore, as is clear from FIG. 14, in order to surely make the stress during film formation the tensile stress, the film formation temperature is set to 57.
It is necessary to set the temperature to 5 ° C or lower. If the temperature is set to such a value and a tensile stress is generated during film formation, and the tensile stress is relaxed to substantially zero in the heat treatment in the subsequent step, the structure will buckle and deform during that time. Never.

14 and 15 show the results using the same device. Subsequently, as shown in FIG. 8, in order to form a fixed electrode of the sensor composed of an N-type diffusion layer, a movable electrode 24 is formed on the insulating film 22 through a photolithography process.
The openings 26 and 27 are formed in a self-aligned manner with respect to.
Further, in order to form the source / drain of the transistor, the opening 2 is formed by the resist 28 through a photolithography process.
9 and 30 are formed.

Further, impurities are introduced into the movable electrode 24 and the gate electrode 25 from the openings 26 and 27 of the insulating film 22 and the resist 28 and the openings 29 and 30 of the resist 28 by self-alignment such as ion implantation. As shown in FIG. 9, the fixed electrodes 31, 32 of the sensor made of an N-type diffusion layer,
Source / drain regions 33 and 34 of the transistor are formed.

Next, as shown in FIG. 10, the movable electrode 2
4. An interlayer insulating film 35 for electrically insulating the gate electrode 25 and the aluminum wiring is formed. Then, as shown in FIG. 11, the wiring diffusion layers 18, 19, 2 are formed on the interlayer insulating film 35.
Contact holes 36, 37, 38, 39 for electrically connecting 0, 21 and aluminum wiring are formed through a photolithography process.

Further, as shown in FIG. 12, a film of aluminum as an electrode material is formed, and aluminum wirings 40, 41, 42, 43 and the like are formed through a photolithography process. Then, as shown in FIG. 13, the sacrificial layer that is a part of the interlayer insulating film 35 and a part of the insulating film 22 is etched. Thus, the manufacturing process of the mechanical quantity sensor device of the transistor type semiconductor is completed.

In this embodiment, the substrate temperature is 570 ° C.
Although the residual stress in the polysilicon can be reduced to almost 0 at a heat treatment temperature as low as 950 ° C. by forming the polysilicon by the method, the N-type impurity diffusion layer 18, which has been previously introduced into the P-type silicon substrate, 19, 20, 2
It is no longer possible for 1 etc. to diffuse into other regions due to heat. Therefore, as in the present embodiment, a semiconductor dynamic quantity sensor device (left side) and its processing circuit (right side) are provided on the same substrate.
Can be formed. Although the annealing time is set to 3 hours in the present embodiment, the crystal grain size of polysilicon can be 100 nm or less, that is, the residual stress can be reduced even by the heat treatment shorter than this. Although the annealing is performed in the next step of forming the beam-shaped portion by etching in this embodiment, it may be performed anywhere between the polysilicon film forming step and the electrode forming step of FIG.

The operation of the semiconductor dynamical amount sensor device having the polysilicon beam-shaped portion formed as described above will be described with reference to FIG. When a voltage is applied between the movable electrode 4 and the silicon substrate 1 and between the fixed electrodes 8 and 9, an inversion layer 16 is formed and a current flows between the fixed electrodes 8 and 9. If the movable electrode 4 is displaced in the Z direction (direction perpendicular to the substrate) shown in the figure by the acceleration of the semiconductor dynamical amount sensor device, the carrier concentration of the inversion layer 16 increases due to the change of the electric field strength, and the current is increased. Increase. As described above, the semiconductor dynamical quantity sensor device can detect acceleration by increasing or decreasing the amount of current.

As described above, in this embodiment, the insulating film 22 (sacrificial layer) is formed on the main surface of the P-type silicon substrate 17 (semiconductor substrate).
After that, polysilicon (polycrystalline silicon) was deposited on the insulating film 22 (sacrificial layer) while keeping the P-type silicon substrate 17 at 570 ° C. constant. Then, this polysilicon is partially removed by etching to remove the beam-shaped movable electrode 2
4 was formed and annealed at 950 ° C. for 3 hours in an inert gas atmosphere. Then, the impurities are diffused into the P-type silicon substrate 17 (semiconductor substrate) in a self-aligning manner with respect to the movable electrode 24 to fix the fixed electrodes 31, 32 on both sides of the movable electrode 24.
Then, the insulating film 22 (sacrificial layer) under the movable electrode 24 was removed by etching.

As a result, as shown in FIGS. 1 to 3, a P-type silicon substrate 1 (semiconductor substrate) and a P-type silicon substrate 1 are used.
A movable electrode 4 having a beam structure and made of polysilicon having a crystal grain size of about 50 nm, which is arranged above the (semiconductor substrate) with a predetermined interval, and a P-type silicon substrate 1 (semiconductor substrate).
Fixed electrodes 8 and 9 formed of impurity diffusion layers formed in self-alignment with the movable electrode 4 on both sides of the fixed electrode 8 and 9 and generated by displacement of the movable electrode 4 due to the action of acceleration. The acceleration is detected by the change (increase / decrease) in the current during the period.

As described above, in order to form the beam-shaped portion, a sacrificial layer was formed in advance and then polysilicon was formed. After forming the beam shape, the sacrificial layer was removed by etching. Here, the sacrificial layer generally refers to a thin film layer formed in advance for the purpose of finally removing and eliminating the sacrificial layer to form the movable portion. Therefore, it is possible to reduce the variation in the gap between the fixed electrode and the movable electrode. Generally, the carrier concentration of the inversion layer of the transistor is inversely proportional to the size of the air gap, and thus the current is also inversely proportional to the size of the air gap. In this example, the size of the void is controlled by the film thickness of the sacrificial layer, and since the film thickness controllability by the method is good,
The controllability of the current value between the fixed electrodes can be significantly improved. Here, the deposition substrate temperature of polysilicon is set to 57
By setting the temperature to 0 ° C., the residual stress value can be maintained on the tensile stress side.

Further, a transistor structure is provided in which a pair of fixed electrodes are provided on a silicon substrate facing in the direction perpendicular to the beam forming the movable electrodes, and a current is generated between the fixed electrodes to change the current by the displacement of the movable electrodes. And
Therefore, the displacement of the movable electrode can be detected from the change in the current between the fixed electrodes to measure the acceleration. In a transistor, normally, the drain current is changed by changing the gate (here, corresponding to the movable electrode) voltage. However, changing the gap between the gate and the substrate also changes the carrier concentration in the inversion layer, so that the drain current is changed. Change. Therefore, in this embodiment, it is possible to detect the change in the movable electrode that has been subjected to acceleration by the amount of current between the fixed electrodes. Since the current can be detected, the large electrode area required in the capacitance detection method is unnecessary, and the miniaturization of the sensor is significantly improved.

Further, the two fixed electrodes are constituted by a diffusion layer which is formed in a self-aligning manner after forming the shape of a beam which becomes a movable electrode. According to such a method, a beam shape to be a movable electrode is formed, a sacrifice layer is opened on a portion to be a fixed electrode on a silicon substrate, and then an impurity is introduced into the portion to be a fixed electrode by an ion implantation method. This can be easily achieved. Therefore, it becomes easy to always form the movable electrode in the central portion between the fixed electrodes, and the positioning accuracy in the manufacturing process can be improved.

Further, although all of these are the IC manufacturing process itself and the diversion, in this embodiment, since the residual stress can be almost zero at the heat treatment temperature as low as 950 ° C., the sensor structure can be formed at the same time in the IC manufacturing process. In addition, it is possible to remarkably easily integrate with a circuit, and cost reduction can be realized. Therefore, if it is attempted to form another control circuit (such as a detection circuit of the acceleration detection unit) including the acceleration detection unit and the MOSFET on the same substrate for the purpose of downsizing, etc., the impurities introduced into the substrate as the MOSFET will not generate heat. At the same time, it will be possible to prevent the spread. This is extremely effective in the recent semiconductor technology in which there is a strong demand for miniaturization.

In other words, a large number of circuits are required to increase the circuit scale with the same substrate area, but MO is correspondingly large.
The gate length of the SFET will be reduced. In this case, for example, a gate length of 1 μm or less is inevitably formed. Impurities introduced into the substrate in MOSFETs of this degree cannot be avoided during the high temperature processing that has been conventionally performed, and it can be said that the application of the present invention in this case is extremely effective.

In the present embodiment, the semiconductor dynamical amount sensor device having a double-supported beam structure having two beam-shaped portions has been described, but the present invention is not limited to this, and FIG. The four beam-shaped portions may be used, or the capacitance type semiconductor dynamical amount sensor device may be used. That is, the present invention may have any other configuration as long as it is a semiconductor dynamical quantity sensor device having a beam-shaped portion made of polysilicon or a movable portion (including an electrode portion).

Further, in the present invention, the external force acting on the movable portion refers to any force capable of displacing the movable portion such as various pressures, electrostatic force, electromagnetic force, etc. in addition to the acceleration shown in the above embodiment.

[Brief description of drawings]

FIG. 1 is a plan view showing a semiconductor physical quantity sensor device according to an embodiment of the present invention.

2 is an AA of the semiconductor dynamical quantity sensor device shown in FIG.
FIG.

3 is a BB of the semiconductor dynamical quantity sensor device shown in FIG.
FIG.

FIG. 4 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG.

5A to 5C are cross-sectional views showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG.

FIG. 6 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 7 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 8 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 9 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 10 is a cross-sectional view showing a manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 11 is a cross-sectional view showing a manufacturing process of the semiconductor physical quantity sensor device shown in FIG. 1.

FIG. 12 is a cross-sectional view showing a manufacturing process of the semiconductor physical quantity sensor device shown in FIG. 1.

FIG. 13 is a cross-sectional view showing the manufacturing process of the semiconductor dynamical amount sensor device shown in FIG. 1.

FIG. 14 is a diagram showing stress generated during film formation with respect to a film formation temperature of polysilicon.

FIG. 15 is a diagram showing changes in residual stress with respect to annealing temperature.

16 is a TEM photograph of a section C of the semiconductor dynamical quantity sensor device shown in FIG.

17 is a TEM photograph of a section C of the semiconductor dynamical amount sensor device shown in FIG. 1. FIG.

18 is a TEM photograph of a section C of the semiconductor dynamical amount sensor device shown in FIG. 1. FIG.

19 is a TEM photograph of a section C of the semiconductor dynamical amount sensor device shown in FIG. 1. FIG.

FIG. 20 is a perspective view showing a conventional electrostatic capacitance type semiconductor mechanical quantity sensor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 P-type silicon substrate (substrate) 4 Movable electrode (beam-shaped part, movable part, detecting means, polycrystalline silicon) 8 Fixed electrode (detecting means) 9 Fixed electrode (detecting means) 17 P-type silicon substrate (substrate) 22 Insulation Membrane (sacrificial layer) 24 Movable electrode (beam-shaped part, movable part, detection means, polycrystalline silicon) 31 Fixed electrode (detection means) 32 Fixed electrode (detection means)

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[Procedure amendment]

[Submission date] January 12, 1995

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Claims (9)

[Claims] 1. A first step of forming polycrystalline silicon on a main surface of a substrate, and a second step of partially removing the polycrystalline silicon by etching to form a beam-shaped movable portion, wherein an external force is applied. Is a semiconductor dynamical quantity sensor device configured to detect the external force based on the displacement of the movable part due to the action of the external force detection device. The semiconductor dynamical quantity sensor device includes an external force detection part that detects an external force and outputs a signal. MOS for processing external force detection signal
A substrate is manufactured by forming a control circuit composed of an FET at least on the same substrate surface, wherein the substrate is formed at a predetermined temperature that causes tensile stress in the polycrystalline silicon in the first step. The polycrystalline silicon is formed while maintaining the above condition, and after the second step, the tensile stress generated in the polycrystalline silicon is further relaxed until it becomes substantially zero, and the impurities introduced into the substrate as the MOSFET are removed. A method of manufacturing a semiconductor dynamical amount sensor device, which comprises performing a third step of performing heat treatment on the substrate at a temperature at which diffusion is substantially suppressed. 2. The method for manufacturing a semiconductor dynamical amount sensor device according to claim 1, wherein the set temperature of the substrate in the first step is set to 575 ° C. or lower. 3. The semiconductor dynamic quantity according to claim 1, wherein the set temperature of the substrate in the first step is 570 ° C., and the heat treatment temperature for the substrate in the third step is 950 ° C. Manufacturing method of sensor device. 4. Among various members forming the external force detection unit and the control circuit, a member having a common superposition positional relationship with at least the main surface of the substrate and made of the same material is The method for manufacturing a semiconductor dynamical quantity sensor device according to claim 1, wherein the method is selectively formed in the same step on the main surface of the substrate. 5. A first step of forming an insulating film on a main surface of a substrate, a second step of forming polycrystalline silicon on the insulating film, and a step of partially removing the polycrystalline silicon by etching. The method includes a third step of forming a beam-shaped portion, and a fourth step of forming a beam structure by etching the insulating film below the beam-shaped portion as a sacrifice layer, wherein the beam structure has an external force. A method for manufacturing a semiconductor dynamical quantity sensor device having a movable part that is freely displaced according to the action of, and detecting the external force based on the displacement of the movable part. The beam structure and a control circuit formed of a MOSFET that processes an external force detection signal from the beam structure are formed on at least the same main surface of the substrate, and the beam structure is manufactured. When pulled into polycrystalline silicon The polycrystalline silicon is formed while maintaining the substrate at a predetermined temperature that causes stress, and the tensile stress generated in the polycrystalline silicon by the subsequent fourth step is relaxed to substantially zero and A method of manufacturing a semiconductor dynamical amount sensor device, comprising performing a fifth step of performing heat treatment on the substrate at a temperature at which diffusion of impurities introduced into the substrate as a MOSFET is substantially suppressed. 6. The method of manufacturing a semiconductor dynamical amount sensor device according to claim 5, wherein the set temperature of the substrate in the second step is set to 575 ° C. or lower. 7. The semiconductor dynamic quantity according to claim 5, wherein the set temperature of the substrate in the second step is 570 ° C., and the heat treatment temperature for the substrate in the fifth step is 950 ° C. Manufacturing method of sensor device. 8. Among various members constituting the beam structure and the control circuit, a member having a common superposition positional relationship with the main surface of the substrate and made of the same material is
The method for manufacturing a semiconductor dynamical amount sensor device according to claim 5, wherein the main surface of the substrate is formed in at least the same steps. 9. A semiconductor dynamic quantity sensor having a beam structure including a movable portion formed on a substrate and displaced according to the action of an external force, and detecting the external force by converting the displacement of the movable portion into an electrical output. A device, wherein the movable part and the beam structure are made of polycrystalline silicon,
A semiconductor mechanical quantity sensor device having a crystal grain size of 100 nm or less.