JPH0328732A - Pressure detector and its manufacture - Google Patents

Abstract

PURPOSE:To obtain superior coupling strength and to enable detection with stable output sensitivity by constituting a device with a glass layer of a flat surface coupled with a semiconductor chip and a swelling part which is formed at the peripheral edge of the flat part and holds the chip. CONSTITUTION:A sensing body 2 is made of Fe-Ni-Co alloy, its upper end surface center part is a diaphragm 21 for pressure reception, and an oxide layer 23 is formed over its entire top surface. Paste of low-fusion-point glass is printed on the layer 23 and calcined temporarily to form the glass layer 24 which is about 40 - 60 mum thickness. The swelling part which is about 10 mum height and about 0.75mm wideness is formed at the peripheral edge part of the layer 24. When the size of the semiconductor chip 3 and the size of the layer 24 are denoted as (a) and (b) respectively and the position shift of the chip 3 is set to about <=0.35mm, the chip 3 satisfying the relation of a+1.5<b<a+2.2 mm is placed on the center flat part of the layer 24 and sintered (at about 450 deg.C) and then the chip 3 is pressed by the swelling part and coupled tightly on the body 2. Further, the reverse surface of the chip 3 is coated with an organic binder to preclude the chip shift.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pressure detector suitable for detecting the pressure of high-pressure fluid and a method for manufacturing the same.

[Conventional technology]

Conventionally, pressure detectors for high-pressure fluids have generally been constructed by using a metal diaphragm with excellent pressure resistance in the pressure-receiving diaphragm, and having a strain gauge bonded to the metal diaphragm. .

2. As a strain gauge, a semiconductor strain cage is suitable since it can provide high output sensitivity.
As proposed in Japanese Patent No. 33, it is constructed by glass-bonding a semiconductor chip on which a semiconductor strain gauge is formed onto a metal diaphragm.

(Problem to be solved by the invention) The glass bonding of this semiconductor chip is a metal diaphragm.
After printing a paste-like low-melting glass powder on the second layer and calcining it at a temperature slightly lower than the final firing temperature, a semiconductor chip is placed on the second base and the final firing process is performed to convert the semiconductor chip into a metal diaphragm.
This is a strong bond between the two parts.

Here, when we analyze the state of the glass layer after calcination, we find that the fourth
As shown in the figure, it became clear that the cross section of the glass layer had a thick bulge at the periphery and a flat depression at the center. This occurs when the glass melted at the temperature during calcination hardens due to its inherent viscosity. The glass layer is made of glass pb〇1B2O, and filler PbTj03,Z
Finished thickness of nSI04 glass paste is 40~6.
When the glass layer was formed with a thickness of 0 μm, the peripheral edge of the glass layer had a raised height of about 10 μm and a raised width of about 0.75 mm, as shown in FIG.

Therefore, when a semiconductor chip is bonded onto this glass layer, the following problems arise depending on the size of the glass layer.

That is, as shown in FIG. 5(a), if the flat part size at the center of the glass layer 24 is smaller than the size of the semiconductor chip 3, the semiconductor chip 3 will not sit well, and furthermore, the final firing (bonding) Sometimes, air enters the gap between the semiconductor chip 3 and the glass layer 24, causing air bubbles to form in the glass layer 24, resulting in a problem in that desired bonding strength cannot be obtained.

Further, as shown in FIG. 5(C), if the flat portion size is larger than the size of the semiconductor chip 3, the position of the semiconductor chip 3 may shift due to vibration during the Honshōkai, and the As shown in FIG. 6, there is a problem in that the output sensitivity of the semiconductor chip 3 changes due to this positional deviation.

In addition, Fig. 6(a). (b) is a semiconductor strain gauge 31~
34. In the diagrams showing the positional relationship between the semiconductor chip 3 and the metal diaphragm 2l, (a) is a plan view, (bl is a front view). Also, FIG. 6(C) is not shown in FIG.
FIG. 3 is a characteristic diagram showing the relationship between positional deviation in the y direction and output sensitivity.

The present invention has been made in view of the above facts, and an object of the present invention is to provide a pressure detector that has excellent bonding strength and no variation in output sensitivity, and a method for manufacturing the same.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a pressure sensor in which a semiconductor chip having a semiconductor strain gauge is bonded to the end surface of a pressure receiving metal diaphragm opposite to the pressure introduction side via a glass layer. The glass layer is characterized by having a flat surface to be bonded to the semiconductor chip, and a raised portion formed around the periphery of the flat portion to hold the semiconductor chip, and further comprising: a metal guide for receiving pressure; 1. A glass layer having a flat surface and a raised portion at the periphery of the flat surface is placed on the end surface of the flam on the opposite side to the pressure introduction side, and a semiconductor chip is bonded to the flat surface, and the glass layer is attached to the raised portion. holding the semiconductor chip in a predetermined area determined according to the size of the semiconductor chip; placing the semiconductor chip on the flat surface of the glass layer; There is provided a method for manufacturing a pressure sensor, comprising the step of bonding the semiconductor chip to the end surface G via the glass layer while holding the semiconductor chip.

[Action/Effect]

In the above structure, the semiconductor chips are bonded on the flat surface of the glass layer, and the bonding strength thereof can be made strong.

Furthermore, since the conductor chip is held in the raised area formed at the periphery of the glass layer, it is prevented from shifting, and has the excellent effect of suppressing variations in output sensitivity due to positional shift. There is.

Further, according to the manufacturing method described in Section 12, JX having the above effects
This has the interesting effect of making it possible to manufacture a force detector.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 9 shows the overall configuration of a pressure sensor to which the present invention is applied. Note that FIG. 9(a) is a plan view of the pressure sensor, and FIG. 9(b) is a front sectional view.

In FIG. 9, the pressure sensor's hanging 1 is a cylindrical body having a through hole in the center, and has a flange structure.

There is a sensing body 2 inside the penetrating label of the housing 1.
is inserted through it. The sensing body 2 is a cylindrical body whose upper end is closed and whose lower end is open DL, and the nozzle of the cylindrical body 2 is a pressure introduction path. A tapered stepped portion 22 is provided on the outer periphery of the sensing body 2, and is fitted into a tapered L-snap 11 provided on the inner periphery of the housing 1. An O-ring 2 is attached to the upper part of the stepped portion 22 of the sensing body 2.
6. A groove 25 is provided for inserting the hunk up ring 27.

The sensing body 2 is made of Fe-N, which has a small coefficient of thermal expansion.
It is composed of an i-Co alloy, and its -L end face has a thinner center section as a pressure-receiving diaphragm 2 (see Fig. 1).
b)). The entire L surface of the diaphragm 21 is oxidized to form an oxide layer 23. The semiconductor chip 3 is bonded onto the oxide layer 23 with a low melting point glass layer 24 interposed therebetween.

Note that, assuming that the size of the glass layer 24 is b and the size of the semiconductor chip 3 is a (see FIG. 1(a)), in this embodiment, as described later, a +1.5<b<a+2. 2 (mm) - (1)
It becomes.

As shown in FIG. 2, the semiconductor chip 3
P-type semiconductor strain cages 31, 32, 33, and 34 are formed by doping boron (B) in these locations, and the strain gauges 31, 33 are located directly above the center of the diaphragm 21, and Gauges 32, 34 are located directly above the periphery of diaphragm 21. And these strain gauges 31
34 are connected to each other by electrode leads (not shown) formed on the sil board to form a full bridge as shown in FIG.

In FIG. 9, the L semiconductor chip 3 is connected to a signal processing IC circuit (not shown) formed on a ring-shaped ceramic substrate 5 provided on the upper surface of the housing 1 so as to surround it, and a wire 4. It is connected.

The signal processing circuit is connected to the outside via a seat frame 51, a feedthrough capacitor 52 for removing electrical noise, and a lead wire 53.

A cylindrical cover 6 is fitted onto the outer peripheral edge of the upper surface of the housing 1 via an O-ring 6l. A lead holder 65 is tightly fitted into the opening end of the cylindrical cover 6 on the left side, and the lead wire 53 passes through this lead holder 65 and extends outside the sensor.

In addition, in FIG. 9, 62 is a plate to which the above-mentioned through-hole capacitor 52 is fixed by brazing, 63 is a seal ring,
64 is an upper play 1, 66 is a lead holder, 67 is a spring screw, 7 is a silicon shell that protects the semiconductor chip 3 from the outside air, and 8 is a botting agent that protects the through capacitor 52 and the lead wire 53.

Furthermore, since the sensing body 2 is inserted into the housing 1 by being driven into the housing 1, it is possible to prevent the sensing body 2 from slipping or slipping out, and furthermore, the stress during driving is reduced by the O-ring 26 and the groove 25 for the hack ambling 27, which allows the semiconductor chip to be inserted. 3 can be prevented from acting directly.

FIG. 10 is a cross-sectional view showing an example of how the main pressure sensor is installed. A seal pipe 201 is installed on the inner circumference of the housing 1 in order to introduce high-pressure fluid into the pressure introduction path of the sensing body 2 from the pressure sensor to the no. It is fitted into the detection target 200 and fixed with a bolt 206 and a washer 207. Note that the seal pipe 201 ensures sealing performance with the pressure sensor and the object to be detected 200 by the O-rings 202 and 204 and the hack-up rings 203 and 205, respectively.

Next, the joining mechanism 11I for connecting the sensing body 2 and the semiconductor chip 3 will be explained with reference to FIG.

First, the surface of the sensing body 2 is cleaned with acid and degreased.

The decarburization treatment of the sensing body 2 is carried out by supplying water vapor into a reducing or weakly reducing atmosphere containing a mixture of H2 and N2, and is carried out at 800°C to 1100°C for about 1 hour.

Next, the sensing body 2 is subjected to oxidation treatment.

Oxidation treatment was carried out in 02 atmosphere for 10 minutes in so-o-c.
Or exposed to O at 1000°C for 5 minutes, 1.5 μm
The oxide layer 23 is formed at a depth of ~5.5 μm.

The glass layer 24 is formed by applying a glass paste of low melting point glass (for example, glass paste P b O ) on the oxide layer 23 .
Filler PbTi03 or ZnSiO4 in B203 series)
This is done by printing and calcining (approximately 450"C), and the finished thickness of the glass is 40μm to 60μm.
shall be. The above glass paste is obtained by mixing glass powder into an organic solvent. The semiconductor chip 3 is placed on the above-mentioned calcined glass layer 24 and the semiconductor chip 3 is firmly bonded onto the sensing body 2 by main baking (approximately 450° C.).

However, as described above, the glass layer 24 after calcination is formed with a thick raised portion at the peripheral edge, and the bonding strength and sensor output sensitivity vary depending on the size relationship between the glass layer 24 and the semiconductor chimney 3.

Therefore, as shown in FIG. 5(b), it is necessary to make the size of the central flat portion of the glass layer 24 and the size of the semiconductor chip 3 approximately the same, so that the chip 3 can sit comfortably.

That is, in this embodiment, since the size of the peripheral raised part of the glass layer 24 is 10 μm in height and 0.75 mm in width (see FIG. 4), the size a of the semiconductor chip 3 and the size of the glass layer 24 are 10 μm in height and 0.75 mm in width.
The relationship between the size b of b=a+2XO. '+5 (mm)
- (2).

Further, if the output sensitivity decreases by up to 50%, it can be compensated for by a compensation resistor of an amplifier circuit (not shown) formed on the Cera short link substrate 5 (FIG. 9). That is, the sixth
From the analysis results in Figure (C), in this example, the semiconductor chip 3
The positional deviation is set to 0.35 or less, and the output sensitivity is guaranteed to be 50% or more.

That is, in this embodiment, the size b of the glass layer 24 is set to the size a of the semiconductor chip 3 by a+2X0.75<
Formula (1) is obtained by setting b<a+2 Is going.

Note that in the chip placement step after calcination shown in FIG. 8, a chip guide jig shown in FIG. 7 is used.

In the figure, 701 is an upper guide plate, 702 is a pedestal, and as shown in FIG. 7, the sensing body 2 and the semiconductor chip 3 are accurately positioned.

At this time, the displacement of the semiconductor chip 3 is suppressed by the raised part at the periphery of the glass layer 24, as shown in FIG. By coating and fixing the chip 3 by its surface tension, chip displacement is further prevented. Incidentally, as the organic binder, for example, ethanol, acetone, TVol, hexanol, etc. are used, and this binder volatilizes due to the heat during wood burning.

After the sensing body 2 and the semiconductor chip 3 are bonded as described above, the sensing body 2 with the semiconductor chip 3 bonded thereto is inserted into the housing 1 by driving as described above, and the pressure shown in FIG. Kasensa is in trouble.

In a pressure sensor having such a structure, when the diaphragm 21 is deformed by the introduced pressure, the positioning is controlled by the diaphragm 21, and a strain l3 14 stress is applied to the semiconductor chip 3 which is integrally bonded, and the l-'-conductor strain on the chip 3 is reduced. Gauge 3
The resistance value of 1.33 changes greatly, and a linear and highly sensitive output signal corresponding to the measured pressure can be obtained.

Furthermore, since the semiconductor chimney 3 and the sensing body 2 are bonded as shown in FIG. 5 (t1), the bonding strength is strong and variations in output sensitivity can be suppressed.

13. In the above example, the shape of the glass layer is the same as the one side b)
However, the present invention uses the bulge at the peripheral edge of the glass layer that occurs during glass paste calcination to prevent the semiconductor number from shifting and to position it, and is not limited to the above-mentioned square shape, but may have other shapes as well. Good too. In that case, it is necessary to set the size of the glass layer according to its shape.

Furthermore, the bulge at the peripheral edge of the glass layer varies somewhat depending on the length and thickness of the glass used. Therefore, the numerical value used in the formula ( ) in the above embodiment is not limited to the above value, but can be arbitrarily set depending on the thickness of the glass component used, etc.

[Brief explanation of drawings]

Fig. 1(a) is a plan view showing the main parts of the pressure sensor to which the present invention is applied, and Fig. 1(1) is a front cross-sectional view of the same pressure sensor, with section A in Fig. 9(b) being enlarged. and show. 2 is a plan view of the semiconductor chip, FIG. 3 is a connection diagram of the semiconductor strain gauge, FIG. 4 is a sectional view of the glass layer 24, and FIG. 5(a). (I1
))． (C) is a diagram showing the glass bonding state of the semiconductor dinobu to the sensing body, Figure 6 (a), (
b) is a plan view and a front sectional view showing the relationship between the semiconductor strain gauge and the diaphragm part, respectively, and FIG. 6(C) is the same as FIG. 6(a).
Figure 7 is an explanatory diagram of the main parts of the chip guide jig, Figure 8 is a process diagram showing the glass bonding procedure, Figure 9 (a) 9(b) is a front sectional view of the pressure sensor shown in FIG. 9(a), and FIG. 10 is a diagram showing an example of mounting the pressure sensor shown in FIG. 9. 1... Housing, 2... Sensing body, 3...
・Semiconductor chip, 21...Diaphragm part, 24...
Glass layer. 31-34 semiconductor strain gauge.

Claims (2)

[Claims] (1) In a pressure sensor in which a semiconductor chip having a semiconductor strain gauge is bonded to the end surface of a metal diaphragm for receiving pressure opposite to the pressure introduction side through a glass layer, the glass layer is bonded to the semiconductor chip. 1. A pressure detector comprising: a flat surface; and a raised portion formed around the periphery of the flat portion to hold the semiconductor chip. (2) A glass layer having a flat surface and a raised portion at the periphery of the flat surface is attached to the end surface of the pressure-receiving metal diaphragm on the opposite side to the pressure introduction side, and a semiconductor chip is bonded to the flat surface. forming a predetermined area determined according to the size of the semiconductor chip in order to hold the semiconductor chip in the raised portion; arranging the semiconductor chip on a flat surface of the glass layer; A method for manufacturing a pressure sensor, comprising the step of bonding the semiconductor chip to the end surface via the glass layer so as to hold the semiconductor chip at the raised portion.