JPH11101701A - Pressure sensor chip, its manufacture and catheter with sensor mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor chip being suitable for, for example, a catheter with a sensor mechanism where the machining and forming of a back pressure hole for a pedestal is unnecessary. SOLUTION: A pressure sensor chip 11 has a diaphragm part 13 being formed on a silicon substrate by an etching technique. The surface and rear surface of the diaphragm part 13 function as a pressure-sensitive surface 13a and a back pressure operation surface 13b, respectively. A groove part 21 is formed to connect an etching recessed part 14 at the side of the back pressure operation surface 13b to a side surface 12a of the silicon substrate. When the pressure sensor chip 11 is used for the catheter, the groove 21 becomes a back pressure hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a pressure sensor chip, a method of manufacturing the same, and a catheter having a sensor mechanism.

[0002]

2. Description of the Related Art Conventionally, a catheter using a pressure sensor chip in a sensor section has been known. This type of catheter is classified into a relative pressure type and an absolute pressure type. FIG. 15 shows an example of a conventional relative pressure catheter.

[0003] A distal end opening of a catheter tube 42 constituting the catheter 41 is sealed by a sealing plug 43. Sealing stopper 43 in catheter tube 42
A pedestal 44 made of a silicon substrate is fixed at a position closer to the base end of the tube. A chip mounting recess 45 is formed on the upper surface of the pedestal 44, and a pressure sensor chip 46 is joined thereto. Pressure sensor chip 46
The strain gauge (not shown) formed above is connected to a lead wire 48 via a bonding wire 47 or a wiring pattern (not shown). A diaphragm 49 is formed on the pressure sensor chip 46. Such a diaphragm portion 49 is formed by etching the silicon substrate from the back surface side. The surface of the diaphragm portion 49, which is a pressure-sensitive surface, is arranged so as to face a pressure guiding port 50 provided on the peripheral surface of the catheter tube 42. The pressure guiding port 50 is sealed with a soft material. An etching concave portion 51 exists on the back surface side of the diaphragm portion 49. In the chip mounting concave portion 45 of the pedestal 44, a back pressure hole 52 for communicating the etching concave portion 51 with the region inside the tube (that is, the atmospheric pressure region) is formed. Accordingly, a back pressure acts on the back surface of the diaphragm 49 via the back pressure hole 52.

[0004]

However, in the case of the conventional relative pressure type catheter 41, it is necessary to form the back pressure hole 52 by etching the pedestal 44 as described above. There is a problem that manufacturing becomes more difficult as the process proceeds.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a catheter having a sensor mechanism suitable for miniaturization because it is not necessary to form a back pressure hole in a pedestal. .

Another object of the present invention is to provide a pressure sensor chip suitable for promoting downsizing of a catheter and the like, and a method for manufacturing the same.

[0007]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a silicon substrate is formed by an etching technique, the surface of the silicon substrate functions as a pressure-sensitive surface, and the back surface of the silicon substrate is formed. In a pressure sensor chip having a diaphragm functioning as a back pressure action surface, a pressure sensor is provided, wherein a groove communicating with an etching recess on the back pressure action side and a side surface of the silicon substrate is formed. The chip is the gist. In this case, it is preferable that step portions are formed at both lower side edges of the silicon substrate.

According to the second aspect of the present invention, there is provided a diaphragm formed on the silicon substrate by an etching technique, the surface of which functions as a pressure-sensitive surface, and the back surface of which functions as a back pressure acting surface. A method for manufacturing a pressure sensor chip in which a groove communicating with an etching concave portion on a working surface and a side surface of the silicon substrate is formed, by etching a back surface side of the silicon substrate after a strain gauge forming step. A gist of the present invention is a method of manufacturing a pressure sensor chip, wherein the groove is formed simultaneously with the formation of the etching recess.

According to a third aspect of the present invention, in the semiconductor device according to the second aspect, an opening for exposing a portion corresponding to the etching concave portion and the groove portion is provided on a back surface side of the silicon substrate after the strain gauge forming step. A step of forming a mask, a step of forming a first mask having an opening for exposing a portion corresponding to the etching recess on the second mask, and a step of exposing a portion exposed from the first mask. A first etching step of dissolving and removing with an alkali, a step of removing a first mask after the first etching step, and a second etching of dissolving and removing a portion exposed from the second mask with an alkali And a process.

According to a fourth aspect of the present invention, in the third aspect, when the second etching step is performed, step portions are simultaneously formed on both lower side edges of the silicon substrate. According to the fifth aspect of the present invention, the pressure sensor chip according to the first aspect has the pressure-sensitive surface directed toward the pressure guiding port in the catheter tube provided with the pressure guiding port on the peripheral surface of the catheter tube. In addition, the gist of the present invention is a catheter having a sensor mechanism, characterized in that the steps formed on both lower edges of the silicon substrate are fixed so as to be directly supported by the inner wall surface of the catheter tube.

Hereinafter, the "action" of the present invention will be described. According to the first aspect of the present invention, since the back pressure acts on the back pressure acting surface via the groove which is the back pressure hole, even if the pressure sensor chip is mounted on the pedestal, for example, the back with respect to the pedestal is not affected. Processing and forming of the pressure hole becomes unnecessary. In addition, when a step is formed on both lower side edges of the silicon substrate, for example, even when the pressure sensor chip is fixed inside the cylinder, the step should be directly and stably supported on the inner wall surface of the cylinder. Becomes possible. Therefore, the pedestal itself can be omitted.

According to the second aspect of the present invention, since the groove is formed at the same time as the formation of the etching concave portion, the method is not accompanied by a decrease in productivity and an increase in cost.
Fine grooves can be accurately formed.

According to the third aspect of the present invention, by performing the first etching step, an etching concave portion is formed at a predetermined position on the silicon substrate to a certain depth. Next, by removing the unnecessary first mask, a second mask below the first mask appears. By performing the second etching step in this state, an etching concave portion is completely formed at a predetermined position on the silicon substrate, and a groove is formed at the same time.

According to the fourth aspect of the present invention, since the step is formed at the same time when the etching concave portion is formed, the method is not accompanied by a decrease in productivity and an increase in cost.
A fine step can be accurately formed.

According to the sixth aspect of the present invention, the pressure in the vicinity of the pressure introducing port acts on the pressure-sensitive surface of the diaphragm portion, and the pressure (ie, the back pressure) in the region inside the catheter tube passes through the groove portion. Acts on the opposite back pressure acting surface. Therefore, a deflection corresponding to the difference between the pressures acting on the both surfaces occurs in the diaphragm portion. The pressure sensor chip outputs an electric signal corresponding to the degree of the deflection to the outside.

Further, with this configuration, since the back pressure acts on the back pressure acting surface via the groove as the back pressure hole, even if the pressure sensor chip is mounted on the pedestal, the back of the pedestal with respect to the pedestal is not affected. Processing and forming of the pressure hole becomes unnecessary. Therefore, a pedestal having a simple structure is sufficient, and a structure that can be manufactured relatively easily even if the diameter of the catheter tube is reduced is achieved. Further, with this configuration, when the pressure sensor chip is fixed inside the catheter tube, the step can be directly and stably supported on the inner wall surface of the tube. Therefore, the pedestal itself can be omitted, and as a result, a catheter tube having a smaller diameter can be employed. Therefore, it is possible to further reduce the diameter of the catheter.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment in which the pressure sensor chip of the present invention is embodied in a vascular catheter will be described below with reference to FIGS.
This will be described in detail with reference to FIG.

As shown in FIGS. 1 and 2, the vascular catheter 1 of the present embodiment has a sensor section for sensing blood pressure at a distal end thereof. The catheter tube 2 constituting the catheter 1 is a flexible cylindrical member having a circular cross section, and is formed of a biocompatible resin such as nylon. The distal end opening of the catheter tube 2 is sealed with a sealing plug 3 made of a biocompatible material such as silicone rubber. On the other hand, the inner region of the catheter tube 2 communicates with the atmospheric pressure region at the base end of the tube.

The peripheral surface of the catheter tube 2 and the sealing plug 3
A pressure guiding port 4 is provided at a position closer to the base end of the tube. The portion of the pressure guiding port 4 is sealed by first and second sealing layers 5 and 6 made of a material that is relatively softer than the catheter tube 2. The first sealing layer 5 is
Is formed below the sealing layer 6. In this embodiment,
The first sealing layer 5 is made of silicone rubber, and the second sealing layer 6 is made of relatively soft silicone rubber. The second sealing layer 6 is exposed to an inner region of the catheter tube 2 via an opening formed in the first sealing layer 5.

In the catheter tube 2, a sealing plug 3
The pedestal 7 is fixed at a position closer to the base end of the tube with an adhesive or the like. As the base 7, a bulk silicon substrate or the like is used. Instead of a metal material such as a silicon substrate, for example, a hard glass such as Pyrex glass or the like may be used. The pedestal 7 has a rectangular parallelepiped shape, and both lower side edges thereof are chamfered. The reason for performing such chamfering is to stably fix the pedestal 7 to the concave portion by increasing the area of contact with the inner wall surface of the catheter tube 2.

The upper surface of the pedestal 7 is flat, and the pressure sensor chip 11 is joined thereto using an adhesive.
When glass is used as the pedestal 7, the two 7, 11 may be joined by anodic joining.

The pressure sensor chip 11 of the present embodiment is made of a silicon substrate one size smaller than the pedestal 7. Specifically, a p-type single crystal silicon substrate 12 having a plane orientation of (110) is used as a base, and an n-type single crystal epitaxial growth layer 23 is laminated thereon. At the center of the silicon substrate, a diaphragm portion 13 which is thinner than other portions is formed. The thickness of the diaphragm 13 corresponds to the thickness of the epitaxial growth layer 23. The surface of the diaphragm portion 13 is a pressure-sensitive surface 13a, and the back surface is a back pressure acting surface 13b. Diaphragm part 1
Reference numeral 3 denotes a pressure-sensitive surface 13a arranged so as to face the pressure-guiding port 4, and the second sealing layer 6 is in contact with the pressure-sensitive surface 13a. Accordingly, the pressure-sensitive surface 13a is not exposed on the blood vessel side. The diaphragm part 13 is formed by processing the etching concave part 14 by etching. The diaphragm section 13 has a plurality of diffusion strain gauges 15.
Are formed.

As shown schematically in FIG. 10, on the upper surface of the epitaxial growth layer 23, a thin oxide film (SiO ₂ film) 24 as an interlayer insulating layer is formed. The wiring pattern 1 made of aluminum is formed on the upper surface of the oxide film 24 by a physical film forming method such as sputtering or vacuum evaporation.
6 and bonding pads 17 are formed. Further, a predetermined portion of the oxide film 24, that is, the diffusion strain gauge 1
5, a contact hole 25 for interlayer connection is formed. The contact hole 25 electrically connects the wiring pattern 16 and the diffusion strain gauge 15 under the wiring pattern 16. These wiring patterns 16 are electrically connected to bonding pads 17 arranged on the upper surface of the outer edge of the silicon substrate.
On the upper surface of the oxide film 24, a passivation film (SiN film) 26 for insulating the surface layer is formed by the above-described physical film forming method. Passivation film 2
The bonding pad 17 is exposed from an opening provided in a predetermined portion of No. 6.

Each bonding pad 17 is connected via a bonding wire 18 to a bonding pad (not shown) on the pedestal 7 side. Further, the bonding pad is soldered to a lead wire 19 via a wiring pattern (not shown) formed on the upper surface of the base 7.

The pressure sensor chip 11 has a groove 21 serving as a back pressure hole. The groove 21 extends along the longitudinal direction of the silicon substrate (that is, the longitudinal direction of the tube). The groove 21 allows the etching recess 14 on the back pressure acting surface 13b side to be formed.
And the side surface 12a of the silicon substrate.

Next, a procedure for manufacturing the pressure sensor chip 11 will be described in detail with reference to FIGS. First, a rectangular parallelepiped p-type single crystal silicon substrate 12 having a plane orientation (110) is prepared. Next, an epitaxial growth layer 23 of n-type single crystal silicon is formed on the upper surface of the p-type single crystal silicon substrate 12 by vapor phase growth. Thereafter, an impurity (boron or the like) is implanted and thermally diffused according to a conventional method, and a diffusion strain gauge 15 is formed in a portion to be the diaphragm 13 later. Further, the oxide layer 2 is formed according to a conventional method.
4, the formation of the contact hole 25, the formation of the wiring pattern 16 and the bonding pad 17, the formation of the passivation film 26, etc., to obtain the state shown in FIG. 3.

A layer made of a material for forming a mask is laminated by CVD or the like on the entire back surface side of the silicon substrate after forming the diffusion strain gauge 15 and the like (see FIG. 4). After that, photolithography is performed on the same layer,
A second mask 27 having an opening 27a is formed (see FIG. 5). The opening 27a is provided in the etching recess 1
Only portions corresponding to 4 and the groove 21 are exposed.

A layer made of a material for forming a mask is similarly laminated on the entire back surface of the silicon substrate after the first mask forming step by CVD or the like (see FIG. 6). afterwards,
As a result of the photolithography performed on the same layer, the first mask 28 having the opening 28a becomes the second mask 27
(See FIG. 7). The opening 28a exposes only a portion corresponding to the etching concave portion 14. The material for forming the second mask 27 and the first mask 28 includes, for example, SiN and SiO ₂ .

After the second mask forming step, the portion of the first mask 28 exposed from the opening 28a is subjected to wet etching using alkali as an etchant (first etching).
Etching process). As an etchant, for example, T
MAH (tetramethylammonium hydroxide) or the like is used. As a result, as shown in FIG. 8, the p-type single-crystal silicon substrate 12 is dissolved and removed from the rear surface side, and the etching concave portion 14 is formed to a certain depth.

After the first etching step, the unnecessary first mask 28 is removed, so that the second mask 27 below the first mask 28 appears (see FIG. 9). Examples of the mask removing method include dry etching and shot blast. In that case, the second mask 27
It is desirable to select a mask removal method that has little effect on the mask.

After the mask removing step, the portion of the second mask 27 exposed from the opening 27a is etched using an alkali such as TMAH as an etchant (second etching step). As a result, as shown in FIG. 10, the p-type single-crystal silicon substrate 12 is dissolved and removed from the back surface side, thereby completely forming the etching recess 14 and simultaneously forming the groove 21 having a predetermined depth. . In addition,
At this time, the presence of the epitaxial growth layer 23 causes an electrochemical etch stop.

Here, the amount dissolved and removed in the first etching step is T2, and the amount dissolved and removed in the second etching step is T3. Further, the thickness of the epitaxial growth layer 23 (that is, the thickness of the diaphragm portion 13) is T1 and the total thickness of the silicon substrate is T. Since the etching concave portion 14 is formed through both etching steps, its depth is T2 + T3. This depth (T2 + T
3) is equivalent to a value (T-T1) obtained by subtracting the thickness of the epitaxial growth layer 23 from the total thickness of the silicon substrate. Since the groove 21 serving as the back pressure hole is formed only through the second etching step, the depth thereof is T3.

Next, the sensing operation of the catheter 1 of the present embodiment will be described. When the catheter tube 2 is inserted into a blood vessel, blood pressure acts on the entire sensor unit. At this time, the sealing layers 5 and 6 provided in the inlet 4 are deformed in accordance with the fluctuation of the blood pressure.
Blood pressure acts indirectly on 3a. On the other hand, the pressure-sensitive surface 13a
The back pressure acts on the back pressure acting surface 13b on the side opposite to the back pressure through a groove 21 which is a back pressure hole. Accordingly, the diaphragm 13 is bent corresponding to the difference between the pressures acting on the both surfaces 13a and 13b. Such bending is caused by the strain gauge 15.
Causes a change in the resistance value. Pressure sensor chip 11
Is designed to output an electric signal corresponding to the degree of the bending to the outside via the bonding wire 18 or the lead wire 19.

Now, the characteristic effects of this embodiment will be listed below. (A) In the pressure sensor chip 11 of the catheter 1 of the present embodiment, the back pressure acting surface 13b of the diaphragm 13
Etching recess 14 on the side and side surface 12 of the silicon substrate
and a groove 21 communicating with a. Therefore, the back pressure acts on the back pressure acting surface 13b through the groove 21 which is a back pressure hole. Therefore, even when the pressure sensor chip 11 is mounted on the pedestal 7,
It is not necessary to form a back pressure hole. Therefore, the pedestal 7 having a simple structure as in the present embodiment is sufficient, and a structure that can be manufactured relatively easily even if the diameter of the catheter tube 2 is reduced. Therefore, it is possible to realize a catheter 1 that is smaller than before.

(B) Pressure sensor chip 11 of this embodiment
In the manufacturing method of (1), the groove 21 is formed at the same time in the second etching step for forming the etching recess 14. Further, in this etching step, since the mask 27 for forming the both 14 and 21 is shared, the fine groove 21 can be formed at an accurate position with respect to the etching recess 14. In addition, according to this method, no special process or device is required for forming the groove 21, so that productivity is not deteriorated and cost is not increased. That is, this manufacturing method is extremely suitable for promoting downsizing of the catheter 1.

(C) Pressure sensor chip 11 of the present embodiment
In the manufacturing method, the etching concave portion 14 is formed by the first etching step and the second etching step.
With such a two-stage etching, it is possible to obtain an etched concave portion 14 which is deeper and has excellent dimensional accuracy as compared with the case where the one-stage etching is performed. In addition, the fact that an electrochemical etch stop works due to the presence of the epitaxial growth layer 23 also contributes to facilitating the control of the depth of the etching recess 14.

The present invention is not limited only to the above embodiment, but can be modified as follows, for example. ◎ p-type single crystal silicon substrate 1 other than plane orientation (110)
As (2), for example, a (111) substrate or a (100) substrate may be used. 11 and 12 show the plane orientation (10
0) Another example of the pressure sensor chip 31 using the p-type single crystal silicon substrate 32 is shown. In the pressure sensor chip 31, when the wet etching is performed with an alkali due to the crystal direction, an etching concave portion 14 having a slope as shown in FIG. 11 is formed. Also in this pressure sensor chip 31, the groove 21 as the back pressure hole is formed by the etching recess 1
4 and the side surface 12a of the silicon substrate.

◎ The pedestal 7 may be omitted, as in another example of the blood vessel catheter 36 shown in FIGS. The pressure sensor chip 37 constituting the catheter 36 has a step 38 in addition to the etching recess 14 and the groove 21. A pair of steps 38 are formed on both lower side edges of the p-type single crystal silicon substrate 12. The depth of the step 38 is equal to the depth of the groove 21. Such a step portion 38 is formed at the same time as the second etching step for forming the etching concave portion 14 and the groove portion 21. Therefore, the stepped portion 3 can be formed without deteriorating productivity or increasing costs.
8 can be finely and accurately processed and formed. Further, such another example of the pressure sensor chip 37 can be directly and stably supported on the inner wall surface of the catheter tube 2. That is, if the pressure sensor chip 37 having the step portion 38 is used, the catheter tube 2 having a concave shape is formed.
This is because the area that comes into contact with the inner wall surface increases. As a result, the pedestal 7 itself can be omitted as described above, and the catheter tube 2 having a smaller diameter can be employed. Therefore, the diameter of the catheter 36 can be further reduced.

The sensor section having the pressure sensor chips 11 and 37 may not be directly formed inside the distal end of the catheter tube 2. For example, a sensor unit using the pressure sensor chips 11 and 37 may be formed in a tube member (for example, a stainless steel tube or the like) separate from the catheter tube 2 and attached to the distal end opening of the catheter tube 2.

◎ TM for performing wet etching
As an alkaline etchant other than AH, for example, KO
H, hydrazine, EPW (ethylenediamine-pyrocatechol-water) and the like may be used.

The groove 21 together with the etching recess 14
As a method of forming the steps 38, for example, dry etching may be employed instead of wet etching as in the embodiment.

As the metal material for forming the wiring pattern 16 and the bonding pad 17, for example, gold or the like may be selected in addition to aluminum. When the pressure sensor chip 11 is manufactured, for example, an n-type polycrystalline silicon layer or an amorphous silicon layer may be formed instead of the n-type single crystal silicon epitaxial growth layer 23. However, the configuration of the embodiment using the epitaxial growth layer 23 of n-type single crystal silicon is most preferable from the viewpoint of improving the detection sensitivity.

In place of the diffusion type strain gauge 15 as in the embodiment, a thin film strain gauge made of, for example, chromium or polycrystalline silicon may be formed. The pressure sensor chips 11 and 37 of the present invention may be applied not only to the catheters for blood vessels 1 and 36, but also to catheters for uses other than blood vessels, and may be applied to tactile pressure sensors and the like. .

Here, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below together with their effects. (1) In claim 5, the pressure guiding port portion is a first sealing layer made of a material that is relatively softer than the catheter tube, and is relatively softer than the first sealing layer. A second sealing layer made of the material described above, wherein the first sealing layer is formed below the second sealing layer, and the pressure-sensitive surface is formed on the first sealing layer. A catheter having a sensor mechanism comprising: being in contact with the second sealing layer exposed to an inner region of the catheter tube through the formed opening. With this configuration, the pressure fluctuation in the outer tube region can be reliably transmitted to the pressure-sensitive surface of the pressure sensor chip via the two sealing layers, and the pressure-sensitive surface itself is not exposed to the outer tube region. it can.

(2) The catheter according to the technical concept 1, wherein the catheter tube, the first sealing layer, and the second sealing layer are both made of a biocompatible material. With this configuration, a catheter suitable for use in a living body can be realized.

The technical terms used in this specification are defined as follows. "Biocompatible material: A material having low reactivity with blood, body fluid, lymph, and other biological substances. For example, resins such as silicone resin, epoxy resin, polyvinyl chloride, and nylon; metals such as stainless steel and gold; There are ceramics such as alumina and zirconia. "

[0047]

As described in detail above, according to the first aspect of the present invention, it is possible to provide a pressure sensor chip suitable for promoting downsizing of a catheter or the like.

According to the second to fourth aspects of the present invention, it is possible to provide a method of manufacturing a pressure sensor chip suitable for promoting downsizing of a catheter or the like. According to the fifth aspect of the present invention, since there is no need to form a back pressure hole in the pedestal, it is possible to provide a catheter which is relatively simple to manufacture despite its small diameter. Further, since the pedestal itself can be omitted, the diameter of the catheter can be further reduced.

[Brief description of the drawings]

FIG. 1 is a partial schematic cross-sectional view showing a sensor section of a vascular catheter according to one embodiment of the present invention.

FIG. 2 is a schematic sectional view taken along line AA of FIG.

FIG. 3 is a schematic cross-sectional view of a silicon substrate for explaining a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 4 is a schematic cross-sectional view of a silicon substrate for explaining a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 5A is a schematic cross-sectional view of a silicon substrate for describing a manufacturing procedure of the pressure sensor chip of the embodiment, and FIG.
Is a bottom view, and (c) is a schematic cross-sectional view taken along line BB of (b).

FIG. 6 is a schematic cross-sectional view of a silicon substrate for explaining a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 7 is a schematic cross-sectional view of a silicon substrate for describing a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 8 is a schematic cross-sectional view of a silicon substrate for explaining a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 9 is a schematic cross-sectional view of a silicon substrate for describing a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 10 is a schematic cross-sectional view of a silicon substrate for describing a manufacturing procedure of the pressure sensor chip of the embodiment.

FIG. 11 is a bottom view of another example of a pressure sensor chip.

FIG. 12 is a schematic side view of the pressure sensor chip of FIG. 11;

FIG. 13 is a partial schematic cross-sectional view showing a sensor section of another example of a vascular catheter.

FIG. 14 is a schematic sectional view taken along line CC of FIG. 13;

FIG. 15 is a partial schematic cross-sectional view showing a sensor section of a conventional catheter.

[Explanation of symbols]

1, 36: a catheter having a sensor mechanism; 2, a catheter tube; 4, a pressure guiding port; 11, 37, a pressure sensor chip; 12, a p-type single crystal silicon substrate, which is a main part of a silicon substrate; Side surface, 13: diaphragm portion, 13a: pressure-sensitive surface, 13b: back pressure acting surface, 1
4 Etching recess, 15 Diffusion strain gauge, 21 Groove, 27 Second mask, 27a, 28a Opening, 2
8 first mask, 38 step.

Claims (5)

[Claims] 1. A pressure sensor chip having a diaphragm formed on a silicon substrate by an etching technique and having a surface functioning as a pressure-sensitive surface and a back surface functioning as a back-pressure acting surface, wherein the back-pressure acting surface is A pressure sensor chip, wherein a groove communicating with an etching concave portion on the side and a side surface of the silicon substrate is formed. 2. An etching recess formed on a silicon substrate by an etching technique, the surface of which functions as a pressure-sensitive surface, and the back surface of which functions as a back-pressure acting surface. A method of manufacturing a pressure sensor chip in which a groove communicating with a side surface of the silicon substrate is formed, wherein the etching concave portion is formed by etching a back surface side of the silicon substrate after a strain gauge forming step. And forming the groove at the same time. 3. A step of forming a second mask having an opening for exposing a portion corresponding to the etching recess and the groove on the back surface side of the silicon substrate after the strain gauge forming step; Forming a first mask having an opening exposing a portion to be formed on the second mask; a first etching step of dissolving and removing a portion exposed from the first mask with an alkali; 3. The method according to claim 2, further comprising: a step of removing the first mask after the first etching step; and a second etching step of dissolving and removing a portion exposed from the second mask with an alkali. 3. The method for manufacturing a pressure sensor chip according to claim 1. 4. When the second etching step is performed,
4. The method according to claim 3, wherein a step is formed at both lower side edges of the silicon substrate. 5. The pressure sensor chip according to claim 1, wherein the pressure sensing surface is directed to the pressure guiding port side in a catheter tube having a pressure guiding port provided on a peripheral surface of the catheter tube, and a silicon substrate is provided. A catheter having a sensor mechanism, characterized in that steps formed on both lower side edges of the catheter tube are fixed so as to be directly supported by the inner wall surface of the catheter tube.