KR970010657B1 - Semiconductor type differential pressure measurement apparatus and method for manufacturing the same - Google Patents

Abstract

No content

Description

Semiconductor type differential pressure measuring device and its manufacturing method

1 is an explanatory diagram showing the configuration of a conventional apparatus;

2 is an explanatory diagram showing the main components of an embodiment of the present invention;

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a cross-sectional view taken along the line A-A of FIG.

5 is a cross-sectional view taken along the line A-A of FIG.

6 is a detailed explanatory diagram showing the main part of FIG. 2;

7 is an explanatory diagram showing an etching process of the structure shown in FIG.

8 is an explanatory diagram of the structure shown in FIG.

9 is an explanatory diagram showing the epitaxial growth method showing the structure of FIG.

10 is an explanatory diagram showing a polishing process of the structure shown in FIG.

FIG. 11 is an explanatory diagram showing a step of forming a recess of the structure shown in FIG.

12 is an explanatory diagram showing a drilling process of the structure shown in FIG.

13 is an explanatory diagram showing an etching process of the structure shown in FIG.

14 is an explanatory diagram showing a joining process of the structure shown in FIG.

15 is an explanatory diagram showing a main part structure of another embodiment of the present invention;

16 is a detailed explanatory diagram showing the main parts of FIG.

17 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

18 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

19 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

20 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

21 is an explanatory diagram showing the operation of the structure shown in FIG.

FIG. 22 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

23 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

24 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

25 is an explanatory diagram showing the operation of the structure shown in FIG. 16;

FIG. 26 is an explanatory diagram showing a main part structure of another embodiment of the present invention; FIG.

27 is a cross-sectional view taken along the line C-C of FIG. 26,

28 is a detailed explanatory diagram showing the main part of FIG. 27;

FIG. 29 is an explanatory diagram for main parts of an embodiment of means for determining an overpressure of the structure shown in FIG. 26;

30 is an explanatory diagram showing the operation of the structure shown in FIG. 26;

FIG. 31 is an explanatory diagram showing the operation of the structure shown in FIG. 26;

32 is an explanatory diagram showing an etching hole according to another embodiment of the present invention;

33 is an explanatory diagram showing a step for forming another epitaxial growth layer 205 according to the present invention;

34 is an explanatory diagram showing a step for forming another silicon oxide layer 206 according to the present invention;

35 is an explanatory diagram showing a step for forming another epitaxial growth layer 207 according to the present invention;

36 is an explanatory diagram showing another polishing step according to the present invention;

37 is an explanatory diagram showing a step showing another step for removing the silicon oxide layer 206 according to the present invention;

38 is an explanatory diagram showing another step for forming the concave portion according to the present invention;

40 is an explanatory diagram showing another process for removing the silicon oxide layer 203 by etching according to the present invention;

41 is an explanatory diagram showing another bonding step according to the present invention;

42 is an explanatory diagram showing an etching process according to still another embodiment of the present invention;

43 is a plan view of the structure shown in FIG. 42,

44 is an explanatory diagram showing a step for forming the Daron epitaxial growth layer 305 according to the present invention;

45 is an explanatory diagram showing another polishing step according to the present invention;

FIG. 46 is an explanatory diagram showing another step for forming the concave portion 306 according to the present invention;

47 is an explanatory diagram showing another step for drilling the hole 307 according to the present invention;

48 is an explanatory diagram showing another process for removing the silicon oxide layer 303 by etching according to the present invention;

49 is an explanatory diagram showing another bonding step according to the present invention;

50 is an explanatory diagram showing an etching apparatus according to another embodiment of the present invention;

5L is an explanatory diagram showing the operation of another embodiment of the present invention;

52 is an explanatory diagram showing the operation of another embodiment according to the present invention;

53 is an explanatory diagram showing the operation of another embodiment according to the present invention.

* Explanation of symbols for main parts of the drawings

1: housing 2,3: flange

4,5: entrance 6,29: thread

7,23 partition 9: support stand

10,11: liquid separation chamber 10A, 11A: back plate

16, 17: connection part 21: first room

22: silicon substrate 24, 51: first connection hole

25: recess 26: second chamber

27: strain detection element 28: support substrate

31: Lead 32: Contact

33: groove 41: filter unit

42, 52: second connection hole 53: protrusion

61: first deformation detection element 62: second deformation detection element

65: CPU 68: judgment signal

71: detection signal 80: strain gage

82: terminal 101: wafer

102 pattern 103 silicon oxide layer

104: silicon layer 105,205,305: epitaxial growth layer

106: recess 107: hole

203: silicon oxide layer 204: silicon layer

206,304 Silicon oxide film 271,272 Strain detection device

303: oxidized sacrificial layer 307: hole

d: gap

The present invention relates to a compact and inexpensive differential pressure measuring device having a simple structure, without any special pressure-resistant casing or any protective device against overpressure before finishing, and manufactured without a pressure-resistant sealing terminal.

The present invention also relates to a semiconductor type differential pressure measuring device comprising measuring partitions provided on both sides of two measuring chambers each having a set space so that the overpressure can be immediately connected by the wall of the measuring chamber when supplied to the measuring partition. The present invention relates to a simple and economical semiconductor type differential pressure detecting element which can be put to practical use as a strain detecting element for measuring a differential pressure as an overpressure detecting element, and highly reliable for overpressure detection.

Moreover, this invention relates to the semiconductor type differential pressure measuring apparatus which can manufacture the partition which is economical and has a high precision thickness.

The present invention also relates to a semiconductor type differential pressure measuring apparatus which does not require a partition on a substrate by a sacrificial layer etching method.

1 is a perspective view showing a conventional structure. For example, reference may be made to FIG. 1 of JA-A-59-56137 (symbol JP-A represents a Japanese patent application published and unexamined here).

FIG. 1 flange 2 and flange 3 are assembled are fixed by welding or the like means in the guide for the inlet (5) for guiding the high pressure fluid to the pressure P _H, the fluid of low pressure to a pressure of P _H Inlet 4 is provided on both sides of the flange (2), (3). The pressure measurement chamber 6 formed in the center partition 7 and the silicon partition 8 is provided inside the housing 1.

The central cock 7 and the silicone compartment 8 are fixed to the wall of the pressure measuring chamber 6 for dividing the chamber 6 into two parts. The back plates 6A, 6B are provided on the wall in the pressure stacking chamber 6 in a manner opposite to the intermediate partition 7. The perimeter of the center partition is welded to the housing 1. The silicon partition 8 is made internally from a single crystal substrate. Four strain gauges 80 are formed on one side of the silicon substrate by selective diffusion of impurities such as rods, and the other is processed and etched to form recessed partitions. When the differential pressure of ΔP of the silicon substrate is reached, two of the installed strain gauges 80 are expanded by the remaining two gauges being compressed. This strain gage is connected to a Wheatstone bridge to detect a change in ΔP differential pressure as a change in electrical resistance.

The lead 81 is attached to one end of the modified gate 80 and the other end is connected to the sealed terminal 82.

The sealed terminal is held by the low zone 9. The end of the support 9 facing the pressure measuring chamber 6 is fixed to the silicon partition 8 using low melting point glass or the like, and bonded to it. The pressure guiding chambers 10, 11 are provided between the housing 1 and the respective flanges 1, 2. The liquid separation chambers 10 and 11 are installed inside the pressure guiding chambers 10 and 11, and the back plates 10A and 11A having shapes similar to the liquid separation partitions 12 and 13 are provided. Is formed on the wall of the housing 1 in a manner opposite to the liquid separation partitions 12, 13. The liquid separation partitions 12 and 13 together with the back plates 10A and 11a set a space to be connected to the pressure measuring chamber 6 via the connection holes 14 and 15. The portions 101 and 102 filled with the sealed liquid, such as silicone oil, are formed in the liquid separation partition 12, in such a manner that the sealed liquid reaches the top and bottom of the silicon partition through the connection holes 16 and 17. Between 13 is provided. The sealed liquid is separated in the portions 101, 102 by the central partition 7 and the silicon partition 8 so that both amounts are substantially the same. The structure described below transfers the pressure supplied from the high pressure side by the transfer pressure supplied from the silicon partition 8 to the liquid separation partition 13 through the sealed liquid portion 102. When pressure is supplied from the low pressure side, the pressure exerted on the liquid separation partition 12 on the opposite side is transmitted to the silicon partition 8 through the sealed liquid portion 101. Therefore, it can be seen that the silicon partition 8 is formed by the differential pressure between the high pressure side and the low pressure side pressure. The amount of deformation, ie the deformation, is electrically output by the strain gage 80 for the measurement differential pressure.

As described above, there are disadvantages as follows.

(l) Since the P _H pressure is supplied around the sensor on one side of the differential pressure measuring device, the outside of the sensor must be covered by a pressure-resistant container,

(2) A sealed withstand pressure sealing terminal is required for outputting an electrical signal to the outside of the apparatus,

(3) Since both sides of the silicon are processed, a process for making a sensor is needed in the finished manufacturing method,

(4) Since the sensor has no protection against overpressure, the overpressure protection device must be provided separately.

The present invention is to solve the above problems.

It is an object of the present invention to provide a high performance compact differential pressure measuring apparatus which is economical, does not use any pressure-tight sealed terminals, and does not have any special withstand voltage case or disconnection protection.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is an explanatory diagram showing the main components of an embodiment of the present invention.

3 is a cross-sectional view taken along line A-A outside of FIG. 2, and FIG. 4 is a cross-sectional view taken along line A-A of FIG.

In the drawings, parts having the same functions as shown in FIG. 1 are denoted by the same reference numerals. The parts different from those shown in FIG. 1 are as follows.

In FIG. 2, the first chamber 21 having a very narrow space is provided on the silicon substrate 22 so that the partition 23 is formed. A first connection hole 24 connected to one end of the first chamber 21 is formed on the silicon substrate 22, and the thin film recess 25 is partitioned on the opposite surface provided in the first chamber 21. It is formed in (23).

The second chamber 26 connected to the recess 5 is formed on the silicon substrate 22 and is surrounded by the partition 23 by the second chamber in a ring shape except for the first connection hole 24. . The deformation detection element 27 is formed on the partition 23 toward the recess 25. The support substrate 28 is connected with the recess 25 by one surface of the silicon substrate 22 formed in the recess, and forms the chamber 29 and the second chamber 26.

As shown in FIG. 5, the connection part 31 is formed by implanting impurities in the bonding surface between the silicon substrate 22 and the support substrate 28, and is connected to the deformation detection element 27 at one end. In FIG. 5, the contact 32 is formed on the support substrate 28 on the bonding surface of the silicon 22, and is connected to the connecting portion 31 at one end.

As in FIG. 5, the groove 33 is formed on the silicon substrate 22 near the contact 32. The groove 33 provides a suitable repulsive force to the connection between the silicon substrate 22 and the contact 32 in order to be properly connected between the contact 32 and the connection 31. Also, in FIG. 6, the filter part 41 is formed in the silicon substrate 32 to prevent the contents contained in the fluid, that is, the pressure medium from entering the first chamber 21 or the chamber 29. In FIG. In this embodiment two filter portions are formed on the substrate.

Undesired dust or particulate content is removed by performing a semiconductor manufacturing process so that a sufficiently small gap d for the filter portion 41 is formed. That is, the gap d of the filter part 41 is small enough to satisfy the relationship of d≤AB, where A means the space of the first chamber 21, and B is the space of the partition 23. Indicates displacement. One of the filter portions 41 is connected to the first connection hole 24, and the other is connected to the seal 29 via the second connection hole 42.

The first connection hole 51 for guiding the pressure is formed on the support substrate 28 and is connected to one side of the filter portion 41.

The other end of this hole 51 lies in the atmosphere. A second connection hole 52 for guiding pressure is formed on the support substrate 28 and connected to one side of the filter portion 41. The other end of this hole 52 lies in the atmosphere.

The protruding portion 53 is connected to the second chamber 26 and the protruding portion 53 is formed to be subjected to high pressure in the case of high pressure, thereby preventing the large stress generated from the junction between the silicon substrate 22 and the supporting substrate. do. In the above structure, the measured pressure on the high pressure side is supplied to the first chamber 21 while the low pressure side is supplied to the chamber 29.

As a result, the silicon partition 23 is formed by the differential pressure between the high and low pressure sides, and the generated strain is electrically detected by the strain detecting element 27. Therefore, the differential pressure is measured by outputting an external deformation as an electrical signal through the lead 31 and the contact 32. When the overpressure is supplied to the first chamber, the wall of the second chamber is in contact with the partition 23, while when the overpressure is supplied to the chamber 29, the wall of the first chamber 21 is connected to the protrusion 23. You will come across.

The manufacturing process of the apparatus having the structure described below will be described as follows with reference to the processes in the order shown in FIGS.

The pattern 102 required in FIG. 7 is etched onto the SOI (Si on Insulation Layer) by etching the silicon oxide layer 103 and the silicon layer 104 by RIE (reactlveion enhanced). The plan view for explaining the structure is as shown in FIG.

The epitaxial growth layer 105 is formed on the surface of the SOI wafer 101 shown in FIG. The surface of the epitaxially grown layer 105 is polished as shown in FIG. 10 to obtain a mirror surface. In FIG. 11, the epitaxially grown layer 105 is etched by RIE etching to form the recess 106.

As shown in FIG. 12, the holes 107 for etching the buried silicon oxide layer 103 are formed by either RIE etching or wet etching using potassium hydroxide. The surface of the silicon oxide layer 103 is etched with a water-soluble fluorine hydrogen solution or hydrogen fluoride gas, as shown in FIG. The silicon substrate 22 is oxidatively connected to a support substrate 28 made of pyrex gas.

The structure thus obtained is a device having the following effects as a result.

(1) The device does not need any special pressure-resistant container, since the outside of the differential pressure sensor can be exposed to atmospheric pressure,

(2) The apparatus does not require a high pressure-sealed terminal for drawing electrical signals into the vortex;

(3) The silicon wafer is mechanically formed only on one side, so the manufacturing process is simple,

(4) Since the sensor itself is processed and formed as above, the apparatus does not need to separate and protect against excess pressure,

(5) Since the extension of the external separation that deforms the partition 23 can be avoided as a result of the second chamber 26 surrounded by the first chamber 21, the chamber 29 and the partition 23, the differential pressure The measuring device is advantageous from sleeping.

From the foregoing description, the present invention can economically provide a high-efficiency small vehicle withstand pressure measurement device without using any terminal sealed with internal pressure, and without using separate protective processing or overpressure protection casing. Able to know.

In FIG. 15, which is a perspective view showing the main part of the apparatus according to another embodiment of the present invention, the structure of the apparatus is as follows.

The device according to the invention is characterized in that a third connecting hole 54 is provided on the support substrate 28 to guide the pressure and connect directly to the seal 29.

The support substrate 28 is made of silicon or polysilicon (polycrystalline silicon) instead of pytex. The silicon substrate having not only the SOI substrate but also the patterned silicon oxide film and the polysilicon growth layer is of course used in the manufacturing process. In the apparatus shown in FIG. 2, the deformation detection elements 27l and 272 are generally provided on the partition 23 in such a manner that high sensitivity is achieved. More specifically, one device is located at the center and the other device is disposed on the edge of the partition 23 to cause reverse phase operation.

The differential pressure measuring device shown in FIG. 2 is subjected to overpressure directly to the partition 23 so that the measurement partition 23 is positioned and immediately functions as a wall or both functions of the first chamber 21 such as the measurement chamber when the measured partition 23 is exceeded. Connect to the room with The deformation generated on the deformation detection elements 271 and 272 is changed non-linearly, and the relationship with the deformation detected by the deformation detection elements 271 and 272 and the pressure supplied are shown in FIG. . The curves indicated by A and B in the graphs are deformation curves obtained by the detection elements 271 and 272, respectively, and the curves indicated by C correspond to the difference between the deformations obtained by the detection elements 271 and 272, respectively. . The process of detecting the overpressure using the deformable elements 271 and 272 is as follows.

(1) As shown in FIG. 18, in the deformation detecting element 272 in which the overpressure is located at the center of the partition 23, the partition 23 is moved to the arrow D before the partition 23 touches the wall of the first chamber 21. As shown in FIG. Tensile deformations can be detected when appearing in the lanyard.

It can be seen from FIG. 19 that the cohesive deformation is detected instead of the tension deformation because the partition moves into the contact at the wall of the first chamber 2l.

In the continuous process of extending the partition 23, the wall of the first wall 21 of the partition 23 is connected to each other as shown in FIG. 20, and the deformation is deformed into tension deformation. The strain detected by the strain detecting element 272 which continuously supplies the overpressure is switched to decrease at medium weight, and is then increased again. The detected transition is shown in the graph of FIG. It can be seen from the above description that there is no one-to-one correspondence between the supply pressure and the strain detected by the strain detecting element 272 alone. Next, as can be seen from the graph of FIG. 12, the detected strain ζ cannot be limited to the set overpressure. This is because the deformation is equally handled by the subwall P1 within the measurement range tolerance or the pressure P2 within the overpressure range.

(2) The deformation detected by the deformation detection element 271 located on the edge of the partition 23 is increased equal to the supplied pressure to be increased.

The relationship between the pressure supplied and the strain corresponds to 1: 1 and the overpressure is defined from the detected strain.

However, in consideration of the practical use of the detection element 271, for example, various changes in temperature and pressure conditions are received. At this time, the state pressure is supplied in addition to the differential pressure instead of the deformation detected by the deformation detecting element 271 including an additional offset. Therefore, the characteristic of the deformation curve represented by E in the graph of FIG. 23 can be replaced by the curve F represented by the same graph.

If the initial strain under overpressure is determined as ζ, the actual overpressure is lowered from P3 to P4 which makes detection impossible.

(3) At this time, it is calculated to remove the influence distributed by the state, that is, the pressure of the state of the difference of the output signal from the deformation detection element 271, and is used to define the overpressure. However, this method cannot be executed again because the difference signal obtained from the strain detection elements 271 and 272 does not correspond 1: 1 to the pressure supplied. This can be clearly seen by FIG. The reason why there is no 1: 1 correspondence in the relationship between the supplied pressure and the detected deformed signal is considered as follows. That is, since the strain detecting element 271 recovers too quickly from the deformed state under compression, even if a difference signal is detected between the detecting elements 271 and 272, the output is equally increased or decreased in such a high pressure state. I can't. In Fig. 25, the relationship between the overpressure supplied by the strain detection element (curve indicated by G) and the detected strain and the pressure given by the strain detection element 271 (curve indicated by H) and the detected strain are given. .

It can be seen from the above description that the overpressure cannot be detected sufficiently precisely by any of the three methods described below.

In addition to the deformation detection elements 271 and 272, a means for providing a detection element for detecting an overpressure may be considered. However, the installation of additional strain detection elements for detecting overpressure requires new structures and integrated electronic circuits. This necessitates an increase in manufacturing cost and additional processing steps in which the manufacturing method must be integrated.

26 shows a perspective view of main parts of another embodiment according to the present invention.

FIG. 27 is a cross-sectional view taken along the line C-C of FIG. In the drawings, parts having the same functions as shown in FIG. 2 are denoted by the same reference numerals. The parts different from those shown in FIG. 2 are as follows.

The first deformation detection element 61 is located at the edge portion of the measurement partition 23. In the second deformation detection element 62, the difference between the output signal and the first deformation element can be converted into a single value function (i.e., the difference signal corresponds to 1 to 1 with respect to the supplied pressure). Located slightly off from

The overpressure detecting means 63 for detecting the difference signal between the signals from the first strain detecting element 61 and the second strain detecting element 62 is supplied to determine whether the overpressure is supplied or not. . For example, in Fig. 29, the overpressure detecting means 63 is composed of a CPU (central processing unit) which performs difference calculation on the signals from the first deformation detection element 61 and the second deformation detection element 62. After comparing the difference signal with respect to the standard signal using the comparator, the determined signal is output as the overpressure determination signal 68.

The detection signal 71 for the measurement pressure difference is output from the result obtained through calculation in the CPU 65. In the apparatus having the structure described below, the measured pressure on the high pressure side and the measured pressure on the low pressure side are respectively supplied to the measuring chambers 21 and 29 provided on both sides of the measurement partition 23. As a result, the silicon partition 23 is formed corresponding to the differential pressure between the supplied high and low pressures. As a result of the deformation of the partition, the signal is electrically detected by the deformation detection elements 61 and 62, and a signal corresponding to the deformation is output to the outside through the lead 31 and the contact 32 to which the differential pressure is applied. When the overpressure is supplied to the partition 23, one wall of the measurement chambers 21, 29 is connected corresponding to the deformed partition.

FIG. 30 shows the relationship between the strain detected by the supplied overpressure and strain detecting element 61 (curve denoted by I) and the detection by the supplied overpressure and strain detecting element 62 (curve denoted by J). The decision system with the given deformation is given. The graph shown in FIG. 31 shows the relationship between the overpressure and the strain difference detected by the detection elements 61 and 62.

When the deformation detecting element 272 is located at the center of the partition 23 as in the conventional structure, the difference signal in the deformation decreases rapidly from the point where the partition 23 contacts the walls of the measurement chambers 21 and 29. The characteristic curve shown is shown. This characteristic curve can be made up to 24 degrees. In contrast with the features of the present invention and the conventional apparatus and features, the present invention exhibits a constant increase curve as shown in FIG. 31, so that the strain is easily determined whether overpressure is supplied or not. It can be expressed as a single value function of the supply pressure (i.e., a 1: 1 correspondence to the supplied pressure). It can be seen that the effect of the device according to the invention is due to the fact that the reduction in the detected deformation of the deformation detection element 62 is slightly delayed by the rapid recovery in the conventional deformation detection element 272.

In particular, it can be seen that the strain recovery only occurs in the fixed portion portion of the strain detection element 62 and does not occur in the vicinity of the other fixed portion. As described above, the difference between the strains detected from the strain detecting elements 61 and 62 can supply the detected overpressure without reducing the strain curve characteristics with respect to the supply pressure. As a result, it is possible to provide a semiconductor type differential pressure measuring device which has high reliability and can detect overpressure. The differential pressure can be detected with high reliability by using a semiconductor differential pressure measuring device provided with a measuring partition 23 that can be immediately connected by the seals 21 and 29. The detection element, that is, the partition 23 One of the elements 62 slightly away from the center of is provided to calculate the difference between the strain detected by the strain detecting element 62 and the strain detecting element 61 formed at the edge portion of the partition 23.

In addition, the apparatus according to the present invention can be manufactured without a separate strain detecting element for overpressure detection, and thus a simple and highly reliable semiconductor type differential pressure measuring apparatus can be produced at low cost. The apparatus according to the present invention can be obtained by slightly changing the position of the strain detecting element in the conventional apparatus.

The device according to the invention can be manufactured by slightly changing the semiconductor manufacturing process, such as by changing the etching pattern. Therefore, it is possible to make a good yield product by fully utilizing the knowledge required in semiconductor manufacturing.

Consequently, the present invention can realize a simple and economical semiconductor type differential pressure side storage value capable of detecting a high reliability overpressure.

In the apparatus shown in FIG. 2, the precision of polishing the partition 23 to a desired thickness is based on the polishing process shown in FIG. In the general polishing method, a precision of ± 5 μm is usually obtained for a polished thickness of 500 μm, and high precision cannot be achieved. The thickness of the partitions used in the device according to the invention is usually 20 μm. However, the ± 5 μm dimensional accuracy is so large that the yield is uneven, increasing the manufacturing cost with low yield.

Another embodiment for solving the problem described above with reference to FIGS. 32 to 41 is as follows. In particular, a method of manufacturing a semiconductor differential pressure measuring device as shown in FIG. 2 will be described. The method of the present invention provides a device for forming partitions so that the dimensions of the thickness are still economically controlled with high precision. As shown in FIG. 32, the SOI wafer having the silicon oxide layer 203 and the silicon layer 204 is subjected to RIE etching to remove the set vicinity 202. As shown in FIG.

In this case, for example, the silicon substrate 204 is usually composed of 600 mu m thick, usually composed of a silicon oxide layer 203 having a thickness of 1 mu m and a silicon layer usually having a thickness of 0.5 mu m. The epitaxial growth layer 205 then grows to a thickness of approximately 20 μm on the surface of the SOI wafer 201. The thickness of the partition 23 depends on the thickness of the epitaxial growth layer 205. The silicon oxide film 206 is then patterned on the peripheral surface of the epitaxially grown layer 205, and this structure is as shown in FIG.

Thus, the patterned silicon oxide film 206 functions as a stopper for selective polishing. In Fig. 35, the epitaxial growth layer 207 is developed to a thickness set on the surface of the epitaxial growth layer 205 obtained in advance. The epitaxially grown layer 207 is formed, for example, usually 5 μm thick. In FIG. 36, the structure is a selective polishing using a silicon oxide film as a stopper, and this process is by mechanical polishing using a polishing solution composed of a weakly alkaline solution having suspended colloidal silica silicon oxide fine particles).

Since the polishing ratio of silicon to silicon oxide film is usually 100, polishing does not exceed the silicon oxide film 206.

The silicon oxide film 206 is then removed by etching given the structure of FIG. The recess 208 is etched on the epitaxial growth layer 205 by RIE etching given the structure shown in FIG. In FIG. 39, the holes 208 for using the silicon oxide layer 203 in the SIO wafer for etching are opened in the epitaxial growth layer 205 by etching using either RIE etching or potassium hydroxide. In FIG. 40, the silicon oxide layer 203 is etched using either a water soluble fluorine hydrogen solution or hydrogen fluoride gas. The silicon substrate 22 is connected to the positive electrode in the support substrate 28 made of Pyrex glass obtained in the structure shown in FIG. Therefore, it is the structure directly obtained by the semiconductor type differential pressure measuring apparatus comprised from the partition 23 which has the thickness controlled with high precision. A partition having high dimensional precision is achieved by patterning the silicon oxide film 206 on the peripheral surface of the epitaxial growth layer 205 and using a selective post-polishing treatment using the silicon oxide film 206 as a stopper.

As a result, this method significantly reduces manufacturing costs. In this case, the partition 23 has a thickness of 20 µm and high precision such as ± 05 µm.

Of course, the SOI substrate is formed by a silicon substrate obtained by forming a patterned silicon oxide film and forming a polysilicon film.

It can be seen from the above description that the present invention provides a method of manufacturing an economical semiconductor type pressure side device capable of realizing high-precision partitions. In the apparatus shown in FIG. 2, the sacrificial layer etching technique can be provided by the installation of the first chamber 21 between the partition and the silicon substrate 22.

An etching technique relating to the method of the first sacrificial layer is provided between the substrate and the structural layer (the layer serving as the construction of the structure), and finally the sacrificial layer is alone by selective etching to provide an opening between the structure and the substrate. Removed.

To explain this process in detail, for example, reference may be made to a new cooling and drying process for the sacrificial insect etching process published by the Japan Electric Association Regular Meeting No. 1992 No. 497.

However, as shown in FIG. 2, the manufacture of the apparatus has the following problems.

When the partition 23 is dried after washing, the partition 23 tends to be adsorbed into the silicon substrate 22 by the surface tension of the cleaning solution, and the partition is not easily separated from the silicon substrate 22. As a means for solving the above problems there is provided a freezing and drying process that is a configuration for freezing the washing solution before drying and sublimation of the freezing wash solution.

However, a temperature control process of the wafer is needed to prevent separation of the cleaning solution during sublimation. In addition, it is necessary to prevent dew condensation generated when the air opened when the sublimation is completed touches the wafer. Therefore, this process is difficult to implement and requires a complicated process. The surface of the partition 23 and the silicon substrate 22 are adhered to each other after etching the silicon oxide layer 103 because the hydroxyl ion (OH ⁻ ) groups are bonded to the surface silicon atoms. The silicon atoms are bonded by oxygen atoms so that these OH ⁻ groups immediately generate H ₂ O, respectively.

Another embodiment of the present invention for solving the problems constantly in FIGS. 42 to 49 is as follows. A method for manufacturing a semiconductor differential pressure measuring apparatus free from the adhesion of the partition 23 and the silicon substrate 22 to each other is as follows. In FIG. 42, the SOI wafer has a silicon oxide layer 303, where the silicon oxide layer 304 is RIE etched to remove the set portion 302. FIG. 43 shows a plan view of the structure shown in FIG. An epitaxial growth insect 305 is formed on the surface of the SOI wafer 301, and the structure is shown in FIG. 44.

In FIG. 45 the surface of the epitaxially grown layer 305 is polished to obtain a mirror surface. The epitaxial growth layer 305 thus obtained is then RIE etched to give the recess 306, the structure shown in FIG.

Holes 307 used to etch the silicon oxide layer 303 embedded in the SIO wafer in FIG. 47 are formed in the epitaxial growth layer by RIE etching or etching using potassium hydroxide.

In FIG. 48, the structure is gas phase etched with a mixed gas consisting of a total amount of hydrogen fluoride gas and wafer vapor using a silicon oxide layer as a sacrificial layer.

The gas phase etching of the victim is, for example, a mixed gas comprising 95% nitrogen gas 4.99% hydrogen fluoride gas and 0.01% steam.

However, it is to be understood that the mixing ratio of the gas components is only a given example, but that other mixed gases can be used for a long time by gas phase etching. The silicon substrate 22 is positively coupled to a support substrate 28 made of Pyrex glass to obtain the structure shown in FIG. The etching apparatus according to the invention is shown schematically in FIG. In FIG. 50 the apparatus consists of a seal K, a support L of a wafer L to be mounted and etched. In this apparatus, gas phase etching is performed by the following reaction formula.

Si0 ₂ + HF + H ₂ O → SiF ₄ ↑ + H ₂ O ↓

Nitrogen (N ₂ ) gas is circulated from this system in sufficient quantities to exit the gaseous silicon fluoride (SiF ₄ ) and water (H ₂ O).

In this manner, the partition and the silicon substrate 22 can be protected from adhesion by the surface tension of the remaining liquid, respectively. The wet etching process is performed on the silicon surface as shown in FIG. 51 by etching silicon oxide (SiO ₂ ).

It can be easily seen that the partition 23 and the silicon substrate 22 are immediately bonded to each other through a solid chemical connection as shown in Fig. 52. In the method according to the present invention, which is clearly distinguished from the wet etching process, the silicon surface is terminated with fluorine atoms to give a large number of inert surfaces even if the silicon surface is heat treated at 900 ° C.

More specifically, reference may be made to Oi Bootsley (Applied Physics) Book No. 59, No. 11 (1990), page 1509, Evaluation of Surfaces Cleaned Using HF Gas.

It can be seen from the above description that the etching of the silicon oxide white layer 303 using vapor phase etching can not only prevent adhesion of the constituent members in the etching hole but also provide an inner surface after etching. Therefore, the process has a definite effect of preventing adhesion.

The etching of silicon oxide using a gas phase etching process using hydrogenated fluorine gas can prevent adhesion of the surface of the component absorbed by the surface tension of the etching solution, and is generated by etching with fluorine atoms for surface non-adhesion. The surface silicon atoms are terminated.

According to the manufacturing method described with reference to FIGS. 42 to 49, the semiconductor differential pressure measuring device is obtained from the adhesion of the partition 23 and the silicon substrate 22 realized according to another embodiment of the present invention. There is no concern.

The present invention has been described in detail from the detailed description, and it is understood that various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims (9)

A semiconductor differential pressure measuring device comprising measuring partitions provided on both sides of a semiconductor device, comprising: a first chamber formed by a predetermined space provided between a silicon substrate and a partition formed on the silicon substrate; A first connection hole whose one end is connected to the first chamber and formed on the silicon substrate; A concave portion formed in the partition on the opposite surface formed in the first chamber; A second chamber connected to the recess, mounted in a shape such as a ring enclosing the first connection hole and enclosing the partition, and having a protrusion formed on the silicon substrate; A second connection hole having one end connected to the protrusion and formed on the silicon substrate; A deformation detecting element provided above the partition on the surface formed in the recess; And a supporting substrate having one surface connected to the surface of the silicon substrate having the recess, the second chamber and the other chamber being formed together with the recess. The semiconductor differential pressure measuring device of claim 1, wherein the support is made of Pyrex. The semiconductor differential pressure measuring device of claim 1, wherein the support is made of silicon. The semiconductor differential pressure measuring device of claim 1, wherein the support is made of polysilicon. 2. The connector of claim 1, further comprising: a connection portion formed of a conductor and formed by injection of impurities into a connection surface between the silicon substrate and the support substrate to which the connection portion is connected at one end thereof; A contact provided on the silicon substrate and having a connection portion connected to one end thereof; And a flaw formed on the silicon substrate in the vicinity of the contact giving proper repulsive force to the connection portion between the silicon substrate and the contact. The method of claim 1, wherein the gap d is sufficiently small so as to satisfy a relationship d≤ (AB), and further comprising a filter in which gaps d are formed at opposite ends of the first and second connection holes, respectively. A semiconductor differential pressure measuring device, wherein A represents a space of the first chamber, and B represents a displacement of the partition. A semiconductor differential pressure measuring device comprising measuring partitions provided on both sides of a semiconductor device, comprising: a first chamber formed by a predetermined space provided between a silicon substrate and a partition formed on the silicon substrate; A first connection hole whose one end is connected to the first chamber and formed on the silicon substrate; A recess formed in the partition on the opposing surface formed in the first chamber; A second chamber connected to the recess, mounted in a shape like a ring surrounding the partition except for the first connection hole, and having a protrusion formed on the silicon substrate; A second connection hole having one end connected to the protrusion and formed on the silicon substrate; A deformation detecting element provided above the partition on the surface formed in the recess; A supporting substrate having one surface connected to the surface of the silicon substrate having the recesses, the second chamber and the other chamber being formed together with the recesses; A first deformation detection element positioned on an edge of the partition on a surface formed on the recess; Positioned in such a way as to be able to output an antiphase signal with respect to the output signal of the first strain detection element, at least within the range permitted by measurement, and output signals of the first and second deformation detection elements as a function of a single value of the supply pressure. A second strain detection element, which is supplied as a difference between the first and second deformation detection elements on a surface formed on the concave portion, and is located at a position slightly away from the center of the measurement partitions: And an overvoltage detecting means for determining whether or not overvoltage is supplied by detecting a difference of an output signal. A method of manufacturing a semiconductor differential pressure measuring device comprising measurement partitions provided on both sides of a chamber, the method comprising: (a) etching a silicon oxide and silicon on a SOI wafer, and (b) liquid on the surface of the SOI wafer. Forming a tactical growth layer, (c) forming a second silicon oxide layer on the surface of the epitaxial growth layer, etching the set portion, and (d) forming an epitaxial growth layer on the surface of the previously formed epitaxial growth layer By forming a tactile growth layer, polysilicon is formed on the surface of the silicon oxide film, (e) selective polishing on the structure using the silicon oxide film as a stopper, and (f) concave on the surface of the epitaxial growth layer. And (g) forming a silicon oxide layer in the SOI wafer by an etching process using RIE etching or alkaline solution. And (h) etching the silicon oxide layer in the SOI wafer using a water-soluble fluorine hydrogen solution or hydrogen fluoride gas, and (i) connecting the supporting substrate to the SOI wafer with a positive electrode. Measuring device. A method of manufacturing a semiconductor differential pressure measuring device comprising measuring partitions provided on both sides of a chamber, the method comprising: (a) etching a set portion of silicon of an SOI wafer using silicon oxidation and RIE etching, and (b) SOI wafer Forming an epitaxial growth layer on the surface of (c) polishing the surface of the epitaxial growth layer to obtain a mirror finished surface, and (d) forming a recess on the surface of the epitaxial growth layer by RIE etching. And (e) forming a hole for etching the embedded silicon oxide layer by an etching process using an RIE etching or an alkaline solution, and (f) using a silicon oxide layer as a sacrificial layer and a fluorine hydrogen solution and water. Vapor-etching the structure with a medium, and (g) connecting the supporting substrate to the SOI wafer with a positive pole.