JPH03218428A - Semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To improve reliability by coupling a semiconductor sensor chip and a pedestal to each other with a silicone basis adhesive agent. CONSTITUTION:The pedestal 2 consisting of silicon is die-bonded by silica paste 5 to a metallic stem 3 and the adhesive agent 6 of a silicone basis is applied atop this pedestal 2. The sensor chip 1 is then die-bonded. The chip 1 and a source 4 are thereafter wire-bonded by using a wire 7. The bonding of the pedestal 2 and the chip 1 is executed by the adhesive agent 6 of the silicone basis having a good thermal characteristic with the semiconductor pressure sensor having such structure and, therefore, thermal strains are hardly generated.

Description

[Detailed description of the invention] of The present invention relates to semiconductor pressure sensors.

Shikadate 11 The semiconductor pressure sensor is shown in the front view in Figure 2 (a) and in the same figure (
As shown in the side view of b), it has a circular thin film diaphragm 11 formed by etching or the like on a silicon substrate 10, and the gauge resistors R1 to R4 made of piezoresistive layers provided on this diaphragm 11 are A or R4. The resistance value changes by receiving pressure in direction B. FIG. 3 shows the connection relationship of these resistors R1 to R4, and the resistor Rl
-R4 is connected to the illustrated rewheatstone bridge. The diaphragm l1 is strained when subjected to pressure, and the resistance values of the resistors R2 and R3 in the central part become large due to tensile stress, and conversely, the resistance values of the resistors R2 and R3 in the peripheral part become small due to compressive stress.

Therefore, the magnitude of the pressure appears in the form of an electrical signal between terminals 12 and 13 in FIG. Note that the resistors R1 to R4 are connected to the power supply Vcc as shown.

In the sensor chip 1 having such a diaphragm 11, when distortion occurs between the diaphragm 11 and its support member, an offset voltage is generated correspondingly.

To avoid this, it is common practice to provide a pedestal between the sensor chip 1 and the metal stem to which it is attached. Conventionally, the pedestal and the sensor chip have been connected using low-melting glass or the like.

However, this has the problem that heat causes distortion between the pedestal and the sensor chip due to the low melting point glass used as the adhesive.

The present invention has been made in view of these points, and it is an object of the present invention to provide a semiconductor pressure sensor that is devised so that thermal strain is less likely to occur.

In order to achieve the above object, the present invention provides a semiconductor sensor comprising a semiconductor sensor chip having a diaphragm provided with a piezoresistive layer, a pedestal to which the semiconductor sensor chip is attached, and a metal stem to which the pedestal is attached. In the pressure sensor, the semiconductor sensor chip is bonded to the pedestal using a silicon adhesive.

With this configuration, the adhesive between the pedestal and the semiconductor sensor chip is resistant to heat, making it difficult for thermal distortion to occur.

EXAMPLE 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, a pedestal 2 made of silicon is attached to a metal slam 3.
die-bonded with silica paste 5, and the pedestal 2
A silicon adhesive 6 is applied to the upper surface of the sensor chip 1, and the sensor chip 1 is die-bonded. After that, sensor chip 1
and sort 4 are wire bonded using wire 7.

The semiconductor pressure sensor having such a structure is resistant to thermal strain because the pedestal 2 and the sensor chip 1 are bonded by a silicon adhesive 6 having good thermal properties.

According to the present invention, since the semiconductor sensor chip and the pedestal are bonded using a silicone adhesive, thermal strain is less likely to occur and reliability is improved. do.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a semiconductor pressure sensor embodying the present invention. FIGS. 2 and 3 are explanatory diagrams of semiconductor sensor chips used therein. 1... Semiconductor sensor chip, 2... Pedestal, 3...
...Metal stem, 4...So6...Silicone adhesive, 11...Diaphragm. Application Population Co., Ltd.

Claims (1)

[Claims] (1) A semiconductor pressure sensor comprising a semiconductor sensor chip having a diaphragm with a piezoresistive layer, a pedestal to which the semiconductor sensor chip is attached, and a metal stem to which the pedestal is attached, in which the semiconductor sensor chip is attached to the pedestal. On the other hand, a semiconductor pressure sensor is characterized by being bonded with a silicone adhesive.