JPS6250633A - Reference pressure type semiconductor pressure transducer - Google Patents

Abstract

PURPOSE:To perform high-reliability sealing in a short time by providing a metallic cap partially with an unwelded zone and sealing the unwelded zone in a chamber of reference pressure by laser light irradiation. CONSTITUTION:A silicon chip 1 where a piezoresistance element is formed is put in the base 3 of a pressure transducer and a thin Au wire 7 is connected thereto. The unwelded zone 10 is provided to part of the metallic cap 9 which covers the base 3. This unwelded zone 10 is put in the chamber 11 set to the reference pressure and irradiated with light from a laser 13 through a transmission window 12 to perform welding in a short time, thus sealing the unwelded zone. The time required for this welding is shortened greatly and the high- reliability sealing is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a reference pressure type semiconductor pressure transducer, and more particularly to a reference pressure type semiconductor pressure transducer that can seal a reference pressure chamber at high speed.

[Background of the invention]

Conventionally, as described in Japanese Patent Application Laid-open No. 58-63826, a hole was made in the upper surface of a metal cap, and a soft brazing material was heated within a standard pressure to seal a standard pressure chamber. However, it is necessary to heat the soft filler metal to a temperature at which it melts within the standard pressure, and then cool it until the soft filler metal solidifies, and no consideration has been given to the time required for heating and cooling.

[Purpose of the invention]

An object of the present invention is to provide a highly reliable reference pressure type semiconductor pressure transducer with a can-seal structure that can perform high-speed reference pressure sealing by high-density energy irradiation.

[Summary of the invention]

The present invention has a structure in which a through hole is provided in a metal cap, the hole is heated and cooled in the normal direction, and the structure is sealed with a soft filler metal. By irradiating the unwelded portion with high-density energy, standard pressure sealing can be achieved in a short time.

[Embodiments of the invention]

Examples of the present invention will be described below.

An embodiment of the present invention is shown in FIGS. 1, 2, and 3.

In the figure, a silicon chip 1 having a piezoresistive element by diffusion on one side, a recess formed on the other side, and a thinned diaphragm is fixed to a glass die 2 with a through hole. A pressure introduction pipe 4 is connected to the base 3, and a pressure to be measured is introduced to the back surface of the silicon chip 1 through these through holes.

Furthermore, a lead pin 5 plated with Au is sealed with a glass seal 6 on the base 3. The input/output terminals on the silicon chip 1 and the lead pins 5 are bonded with Au thin wires 7.

Attach the metal cap 9 to the above base assembly at the partially unwelded part 1.
0 and then welding in the chamber 11 set at the standard pressure, as shown in FIG.

The unmelted portion 10 is sealed by welding with a laser 13 through the transmission window 12 .

According to this embodiment, the reference pressure sealing is performed by laser welding.
It is effective and can be done in a short period of time.

A second embodiment will be explained with reference to FIG.

In this embodiment, when the circumferential protrusion 8 for resistance welding is partially missing from the metal cap 9 and the base 3 is resistance welded,
Since an unwelded portion 10 is formed, the unwelded portion 10 is sealed by laser welding in a standard pressure chamber.

The third embodiment will be explained with reference to FIG.

In this embodiment, when a circumferential protrusion 8 for resistance welding is partially missing from the base 3 and resistance welded to the metal cap 9,
Since an unwelded portion 10 is formed, the unwelded portion 10 is sealed by laser welding in a standard pressure chamber.

〔Effect of the invention〕

As explained above, according to the present invention, since the reference pressure chamber is welded and sealed using high-density energy, the time required for standard pressure sealing can be shortened and highly reliable sealing can be achieved. Become.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 3 are diagrams showing an embodiment of the present invention, and FIG. 4 is a diagram showing a second embodiment of the invention. FIG. 5 is a diagram showing a third embodiment of the present invention, and FIG. 6 is a diagram showing a sealing method. 1... Silicon chip, 2... Glass die, 3...
・Base, 4...Pressure introduction pipe, 5...Lead pin,
6... Glass seal, 7... Au thin wire, 8... Resistance welding protrusion, 9... Metal cap, 1o... Unwelded part, 11... Standard pressure chamber, 12... Laser transmission window, 13...laser.

Claims (1)

[Claims] 1. An input/output lead pin is fixed by a glass seal and a base with a through hole is joined to the base with a hole communicating with the through hole, and a base is fixed on the base and has a hole on one side. It has a silicon chip on which a piezoresistive element is formed by diffusion technology and a thinned diaphragm is formed by forming a recess on the other side, and the input/output terminal of the piezoresistive element on the silicon chip and the lead pin are connected by a thin wire. A reference pressure type semiconductor pressure transducer formed by electrically connecting and welding a metal cap so as to include the silicon chip, the pedestal, the lead pins, and the thin wire, and sealing the inside of the metal cap at a reference pressure, A standard pressure type semiconductor pressure transducer, characterized in that the metal cap has a part of the unwelded part and the unwelded part is sealed within a standard pressure. 2. The reference pressure type semiconductor pressure transducer according to claim 1, characterized in that the metal cap has a portion of the resistance welded circumferential protrusion removed to provide an unwelded portion. .