JP2000131170A - Method of mounting pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the pressure resistance characteristic of a sensor, without being restricted by the parent material strength of glass by directly bonding or adhering a Si member having a diaphragm to a fixing base. SOLUTION: A single-crystal Si member 1 having a diaphragm 1a is formed by the anisotropic or dry etching, etc., of Si and is eutectic-bonded to a fixing base 4 made of Si or metal, etc., which is heat treated at about 400 deg.C, e.g. using an Au-Si alloy solder-made bonding member 5. At this time, about the Si member 1 and the fixing base 4, an Au or Au-Si metal film is metallized on the bonding face of Si or the front face at the bonding face and similarly the bonding face of the base 4 or the front face at the bonding face through plating, deposition, sputtering, etc. As a result, the bond strength is improved, and the pressure resistance characteristic restricted by the parent material of the glass base can be enhanced to improve the reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor pressure sensor used for controlling an engine of an automobile and the like.
The detection unit that detects the pressure of liquids such as gas, oil, and gasoline is mounted by eutectic bonding using lead-free solder, which simplifies the mounting structure, improves the pressure resistance against external forces, and prevents environmental pollution. More particularly, the present invention relates to a method for mounting a pressure sensor which is suitable for the present invention.

[0002]

2. Description of the Related Art As a prior art related to the present invention, a silicon member having a gauge resistor and a diaphragm is bonded to a glass pedestal by an anodic bonding technique, and is bonded and bonded to a fixed pedestal serving as a base substrate of metal or plastic. You. FIG. 2 shows a schematic structure of the prior art. In the drawing, reference numeral 10 denotes a silicon member having a strain gauge resistor 11 formed by diffusion, 12 denotes a diaphragm formed by thinning the silicon member 10 by an isotropic etching process or the like, 13 denotes a glass pedestal, 14 denotes a pressure introducing pipe 15. Is a joining member for joining or bonding the glass pedestal 13 and the fixed pedestal 14.

[0003] As described above, the silicon member is anodically bonded to the glass pedestal in order to reduce the influence of thermal distortion of the fixed pedestal, and further bonded to the fixed pedestal with a metal material such as an organic adhesive or solder.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method in which silicon and glass are anodically bonded and bonded to a fixed base by applying pressure through a pressure introducing pipe as shown in the prior art of FIG. When this is done, a force in the peeling direction is generated at the anodic joint between silicon and glass and the joint between glass and the fixing base. In particular, the anodic joint has a glass base material strength (1 kgf /
If a pressure of more than mm ² ) is applied, the joint will be damaged. Therefore, there is a need for a mounting method that improves the pressure resistance of the sensor without being restricted by the strength of the glass base material.

[0005]

In order to achieve the above object, it is possible to eliminate the anodic bonding portion between silicon and glass and to use mounting means for directly bonding a silicon member to a fixed base with metal such as solder. Further, in order to reduce the thermal effect of the fixing pedestal, the thickness of the solder or the like must be reduced as much as possible.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIG. In the figure, 1 is a single crystal silicon member having a diaphragm 1a, 2 is a strain type gauge 2a, 2b made by processing by an anisotropic etching process or the like.
A single-crystal silicon member having
Is a fixed base made of metal or ceramic or the like having a pressure introducing pipe 4a, 5 is a bonding member for bonding the silicon member 1 and the fixed base 4, and 6 is an electrode for extracting an electric signal. The pad 7 is a stem having lead pins 8. Note that elements having the same numbers, which will be described later, all have the same function.

A silicon member 1 having a diaphragm manufactured by a processing process such as anisotropic etching or dry etching of silicon is bonded to a bonding member 5, for example, a gold-silicon (Au-Si) alloy solder material at about 400 ° C. Is eutectic bonded to the fixing table 4 in the heat treatment process. At this time,
The surface of the silicon member 1 and the fixing table 4 is gold (Au) on the bonding surface or the bonding surface front side of the silicon, and similarly, the bonding surface or the bonding surface of the fixing table 4 is gold (Au) by plating, vapor deposition, sputtering, or the like. Alternatively, a metal film of (Au-Si) is metallized. In addition, Au-Si to the silicon member 1
Eutectic bonding is possible by arranging and heat-treating a preform-shaped thin plate of the same material in place of the metallization.

The connection for taking out an electric signal from the silicon member 2 having the gauge is performed by metallizing the surface of the electric pad 6 and the lead pin 8 in the same manner as described above, and simultaneously with the eutectic bonding of Au-Si during the heat treatment. An electrical connection can be obtained.

Therefore, by directly bonding silicon to the fixed base without using the glass pedestal, the bonding strength can be improved, and at the same time, electrical signals can be extracted, thereby simplifying the manufacturing process.

FIG. 3 shows another embodiment in which the joining members are changed. In the connection member, 5a is, for example, gold-tin (Au-
Sn), tin-silver (Sn-Ag), tin-antimony (Sn
-Sb), eutectic solder such as lead-tin (Pb-Sn) is used. On the other hand, the silicon member and the fixed base 4 need to be metallized as shown in the figure. Here, 5b is aluminum formed on the silicon member 1 by sputtering or vapor deposition.
Silicon / titanium / nickel / gold (Al-Si / Ti /
Ni / Au) and titanium / platinum / gold (Ti / Pt / Au)
And a metallized layer 5c on the side of the fixed pedestal 4 is nickel-plated or nickel-gold plated.

According to this embodiment, the heat treatment process temperature for the Au-Si bonding material can be realized at about 300 ° C. or less. Further, similarly to the above embodiment, the joining member 5a may be a preform-shaped thin plate. Then, the electrode pads 6b, 6
By subjecting c to the same metallization as in 5b, an electrical connection can be obtained.

FIG. 4 shows another embodiment in which the mounting method of the electrode lead portions is changed. In the figure, reference numeral 9 denotes an insulating material such as ceramic, which is a connection terminal portion; 6e, a wire bonding electrode whose surface layer is formed of aluminum or gold;
Is an electrode pad of the silicon member 2, the surface layer of which is formed of aluminum or gold as in 6e. In the embodiment, the metallization similar to that of the silicon member 1 is arranged on one of the connection terminal portions 9, so that the connection terminal portion 9 can be simultaneously bonded in the step of bonding the silicon member 1 and the fixing pedestal 4. Signal extraction can be performed by a wire bonding method.

[0013]

According to the present invention, it becomes possible to mount a silicon member having a diaphragm directly on a fixed pedestal by soldering, thereby improving the pressure resistance characteristic limited by the base material strength of a conventional glass base and improving reliability. It can be improved. In addition, the anodic bonding process using a glass table is not required, which has the effect of simplifying the manufacturing process, shortening the time, and reducing the cost.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a pressure sensor according to an embodiment of the present invention.

FIG. 2 is a side sectional view showing a conventional technique of a sensor mounting method.

FIG. 3 is a side sectional view of a pressure sensor showing another embodiment of the present invention.

FIG. 4 is a side sectional view of a pressure sensor showing another embodiment of the present invention.

[Explanation of symbols]

1,10: single-crystal silicon member, 1a: diaphragm,
2 Single crystal silicon member, 2a, 2b Strain gauge,
3 ... insulating layer film, 4, 14 ... fixed base, 4a, 15 ... pressure introduction pipe, 5, 16 ... joining member, 5a, 6a ... solder member, 5
b, 5c, 6b, 6c: metallized layer, 6: electrode pad, 6e: pad electrode, 7: stem, 8: lead pin, 8a: wire, 9: connection terminal, 11a, 11b ...
Diffusion type strain gauge, 13 ... glass stand.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshiyuki Sasada 2520 Ojitakaba, Hitachinaka City, Ibaraki Prefecture Inside the Automotive Equipment Division of Hitachi, Ltd. (72) Inventor Masanori Kubota 2477 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi Car Engineering (72) Inventor Miya Atsushi Atsushi 2520 Takaba, Hitachinaka-shi, Ibaraki Prefecture F-term (reference) 2F055 AA21 BB20 CC02 DD01 DD05 DD09 EE13 FF43 GG12 4M112 AA01 BA01 CA02 CA15 DA20 EA03 GA01

Claims (6)

[Claims] 1. A single-crystal silicon member 1 having a diaphragm that is displaced in response to an external force, a single-crystal silicon member 2 in which a resistance value of a gauge portion is changed in response to a displacement of the diaphragm, A method for mounting a pressure sensor, wherein a silicon member 1 having a diaphragm is directly bonded or bonded to a fixed pedestal in a semiconductor pressure sensor including an insulating layer arranged to be bonded and a fixed pedestal for fixing the insulating layers. 2. A single-crystal silicon member 1 having a diaphragm which is displaced in response to an external force, a single-crystal silicon member 2 in which a resistance value of a gauge section is changed in response to a displacement of the diaphragm, 2. The method for mounting a pressure sensor according to claim 1, wherein in a semiconductor pressure sensor including an insulating layer arranged so as to be joined and a fixing pedestal for fixing the insulating layer, an improvement in pressure resistance characteristics against an external force can be achieved. 3. A single-crystal silicon member 1 having a diaphragm that is displaced in response to an external force, a single-crystal silicon member 2 in which a resistance value of a gauge portion changes in response to a displacement of the diaphragm, In a semiconductor pressure sensor comprising an insulating layer arranged so as to be joined and a fixing pedestal for fixing them, the joining of the silicon member 1 having the diaphragm to the fixing pedestal is eutectic joining by solder. Item 3. A method for mounting the pressure sensor according to Item 1. 4. A single crystal silicon member 1 having a diaphragm that is displaced in response to an external force, a single crystal silicon member 2 in which a resistance value of a gauge section is changed in response to a displacement of the diaphragm, In a semiconductor pressure sensor consisting of an insulating layer arranged to be joined and a fixing pedestal for fixing them, the joining member is a lead-free solder and is made of a single material or an alloy material obtained by mixing a plurality of materials. The method for mounting a pressure sensor according to claim 1, wherein the pressure sensor is provided. 5. A single crystal silicon member 1 having a diaphragm that is displaced in response to an external force, a single crystal silicon member 2 in which a resistance value of a gauge portion is changed in response to a displacement of the diaphragm, 2. The method for mounting a pressure sensor according to claim 1, wherein in a semiconductor pressure sensor including an insulating layer arranged so as to be joined and a fixed pedestal for fixing the insulating layer, the fixed pedestal is made of a metal or ceramics. 6. A single-crystal silicon member 1 having a diaphragm that is displaced in response to an external force, a single-crystal silicon member 2 in which a resistance value of a gauge portion changes in response to a displacement of the diaphragm, The mounting of the pressure sensor according to claim 1, wherein in a semiconductor pressure sensor including an insulating layer arranged so as to be bonded and a fixing pedestal for fixing them, bonding of a relay terminal member for an electric signal can be performed in a simultaneous step. Method.