CN1279592C

CN1279592C - A method for preparing high power thyristor core

Info

Publication number: CN1279592C
Application number: CN 200410049712
Authority: CN
Inventors: 沈首良
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-06-25
Filing date: 2004-06-25
Publication date: 2006-10-11
Anticipated expiration: 2024-06-25
Also published as: CN1595623A

Abstract

The present invention relates to a method for preparing a high power thyristor core, which belongs to the technical field of semiconductor device manufacture. The method comprises the following steps: a silicon chip, aluminum foil containing silicon and a molybdenum chip are firstly and orderly arranged in a mold according to design thickness; the mold is put in a sintering furnace; vacuum pumping is implemented to 2*10<-2>Pa, and heat insulation is implemented for a period after temperature rise; when temperature is slowly decreased to 480 DEG C, heating stops; the temperature is continuously decreased below 400 DEG C, and heating stops; when the temperature is decreased to 250 DEG C, the vacuum pumping stops; when the temperature is decreased to normal temperature, the high power thyristor core can be obtained. The method for preparing a high power thyristor core of the present invention adopts the aluminum foil containing silicon so that the silicon and molybdenum are sintered together. Thus, the melting point of aluminum foil solder containing silicon can be decreased, and the flowability and the moisture performance of the solder can be enhanced. The interdiffusion and penetration capability among the solder, the silicon chip and the molybdenum chip can also be intensified. Thereby, the thermal stress among silicon, aluminum and molybdenum is decreased, and pipe pressure drop is decreased. The sintering rate of finished products of the thyristor core is enhanced by at least 10%.

Description

A kind of manufacture method of large-powered thyristor die

Technical field

The present invention relates to manufacture method of large-powered thyristor die, belong to the semiconductor device processing technology field.

Background technology

In the production of high-power thyristor; silicon chip through a p type impurity diffusion, oxidation, photoetching, secondary N type diffusion of impurities after; need with the molybdenum sheet sintering together; just become thyristor core through the angle lap corrosion protection again, can wherein last sintering process be the critical process that make a good thyristor core.

The method of existing production thyristor core is that the highly purified aluminium foil of pad a slice is heated to 700 ℃ of left and right sides sintering then under vacuum, make the mutual sintering of silicon chip and molybdenum sheet together between silicon chip and molybdenum sheet after diffusion and the photoetching.The existing methods shortcoming is, rafifinal at high temperature flowability is bigger, combine easily in the heating process and form alusil alloy with silicon, be that the part silicon chip " is eaten up " by aluminium, making in the tube core of last formation does not have aluminium between the silicon chip and molybdenum sheet, forms the cavity in the middle of the perhaps last tube core that forms, and makes tube core thoroughly become waste product, or the change of tube core thermal resistance is big, reduces the capacity of device.

Summary of the invention

The objective of the invention is to propose a kind of manufacture method of large-powered thyristor die, change the sintering process of silicon chip and molybdenum sheet, to improve the quality and the rate of finished products of high-power thyristor.

The manufacture method of large-powered thyristor die that the present invention proposes may further comprise the steps:

(1) silicon chip, siliceous aluminium foil and molybdenum sheet are packed in the mould successively by design thickness, the silicone content in the siliceous aluminium foil is lower than 11.7%, and the thickness of siliceous aluminium foil is 0.025～0.03mm;

(2) above-mentioned mould is put in the sintering furnace, be evacuated to 2 * 10 ^-2Pa is warming up to 700 ℃, is incubated 30～65 minutes;

(3) press 1～2 ℃ of per minute cooling, stop heating when being cooled to 480 ℃;

When (4) furnace temperature is reduced to below 400 ℃, body of heater is removed, stopped to vacuumize when reducing to 250 ℃, be cooled to normal temperature, obtain the high-power thyristor tube core.

The manufacture method of large-powered thyristor die that the present invention proposes, adopt siliceous aluminium foil to make silicon, molybdenum sintering together, both can reduce the fusing point of siliceous aluminium foil scolder, can improve the flowability of scolder again and be stained with the lubricant nature energy, can also strengthen the counterdiffusion mutually between scolder and silicon chip and the molybdenum sheet and the ability of infiltration, thereby improve the sintering quality of silicon, molybdenum.Adopt siliceous aluminium foil sintering, be stained with profit well, be difficult for stream aluminium, thereby reduced the thermal stress between silicon, aluminium, the molybdenum, and reduced tube voltage drop.The sintering finished rate of tube core has improved more than 10%.

Description of drawings

Charging schematic diagram when Fig. 1 is the preparation tube core.

Among Fig. 1, the 1st, briquetting, the 2nd, graphite crucible, the 3rd, molybdenum sheet, the 4th, siliceous aluminium foil, the 5th, silicon chip, the 6th, Graphite pad.

Embodiment

The manufacture method of large-powered thyristor die that the present invention proposes, its charging process be referring to Fig. 1, and at first that clean is good silicon chip 5, siliceous aluminium foil 4, molybdenum sheet 3 and Graphite pad 6 require successively to pack in the graphite crucible 2 as figure according to design thickness.In order to enhance productivity, after many group raw materials of can packing into treat that graphite crucible is filled, put a stainless steel briquetting 1 above again.Graphite crucible 2 after the charging is pushed the flat-temperature zone of sintering equipment, and blow-on heats up and opens mechanical pump and vacuumizes then.

Introduce one embodiment of the present of invention below:

(1) adopt the rafifinal sintering that contains 11% silicon to replace original rafifinal sintering process.

(2) siliceous aluminum foil thickness: 0.028mm.

(3) silicon chip, sial sheet, molybdenum sheet, graphite flake that clean is the good graphite mo(u)ld of packing into.

(4) graphite mo(u)ld is put a stainless steel briquetting above filling the back again.

(5) graphite mo(u)ld that installs is pushed the quartz ampoule flat-temperature zone, inspection is also set and is stablized control program, and blow-on heats up and opens mechanical pump and vacuumizes then.

(6) when vacuum degree reaches 2 * 10-2Pa, advance body of heater, entangle quartz ampoule.

(7) body of heater is entangled quartz ampoule fully, be warmed up to 700 ℃, constant temperature 50 clocks begin cooling.

(8) slow cool-down method is adopted in cooling, and per minute falls 1～2 ℃ and stops heating up to 480 ℃.

When (9) furnace temperature is reduced to below 400 ℃, body of heater is removed, closed diffusion pump when reducing to 250 ℃, close high valve when reducing to 160 ℃, open vacuum chamber and take out tube core.

In the used siliceous aluminium foil of the inventive method, the content of silicon can not be higher than 11.7%, if the content of silicon is higher than 11.7%, then can run counter to desire, and influences the sintering effect of silicon, molybdenum.

Claims

1, a kind of manufacture method of large-powered thyristor die is characterized in that this method may further comprise the steps:

When (4) reducing to below 400 ℃, body of heater is removed, closed diffusion pump when reducing to 250 ℃, close high valve when reducing to 160 ℃, open vacuum chamber and take out tube core.