Boron-aluminum common gettering method for silicon slice

A technology of boron-aluminum and silicon wafers, which is applied in the field of aluminum-boron co-gettering of silicon wafers, to achieve the effects of easy operation, low secondary pollution and good repeatability

Active Publication Date: 2011-01-12
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Therefore, the existing gettering process can no longer meet the technical development requirements of the integrated circuit industry and the photovoltaic industry. If a more effective external gettering process than phosphorus gettering, boron gettering, and aluminum gettering can be invented, it will be It will strongly promote the rapid development of these two industries and related industries

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] (1) Purchase the aluminum paste of the RX8 model from Guangzhou Ruxing Technology Co., Ltd., add diboron trioxide in the aluminum paste, stir evenly, and obtain the mixed slurry; wherein, the particle size of diboron trioxide is 1- 4μm, the mass fraction of boron in the mixed slurry is 3%;

[0036] (2) silicon chip is cleaned with RCA liquid, dry, and wherein RCA liquid comprises No. 1 liquid and No. 2 liquid, and No. 1 liquid is made of ammonia (mass percentage concentration is 30%), hydrogen peroxide (mass percentage concentration is 30%) and remove Ionized water is mixed at a volume ratio of 1:1:5, and the No. 2 liquid is mixed with hydrochloric acid (mass percentage concentration of 36%), hydrogen peroxide (mass percentage concentration of 30%) and deionized water at a volume ratio of 1:1:6 It is made; cleaning with RCA solution, that is, cleaning with No. 1 solution and No. 2 solution in sequence;

[0037] (3) screen-print or spin-coat the mixed slurry prepared in...

Embodiment 2

[0045] Same as embodiment 1, its difference is only: heat treatment takes rapid heat treatment, that is, step (4) is:

[0046] The silicon wafer obtained in step (3) was placed in a rapid heat treatment furnace and heated at 950° C. for 2 minutes under the protection of argon, and the silicon wafer was naturally cooled along with the furnace.

[0047] Carry out performance test to embodiment sample, test method and condition are the same as embodiment one, test result is: the metal impurity content before test is 5.6 * 10 13 atoms / cm 3 ; The metal impurity content after the test was 7.7×10 12 atoms / cm 3 .

Embodiment 3

[0049] (1) buy the aluminum paste of AL53-110 model from Fu Lu (Ferro) new material company, add diboron trioxide in aluminum paste, stir, obtain mixed slurry; Wherein, the particle size of diboron trioxide is 2-5μm, the mass fraction of boron in the mixed slurry is 2.8%;

[0050] (2) silicon chip is cleaned with RCA liquid, dry, and wherein RCA liquid comprises No. 1 liquid and No. 2 liquid, and No. 1 liquid is made of ammonia (mass percentage concentration is 30%), hydrogen peroxide (mass percentage concentration is 30%) and remove Ionized water is mixed at a volume ratio of 1:1:5, and the No. 2 liquid is mixed with hydrochloric acid (mass percentage concentration of 36%), hydrogen peroxide (mass percentage concentration of 30%) and deionized water at a volume ratio of 1:1:6 It is made; cleaning with RCA solution, that is, cleaning with No. 1 solution and No. 2 solution in sequence;

[0051] (3) screen printing or spin-coating the mixed slurry prepared in step (1) on both s...

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Abstract

The invention discloses an aluminum-boron common gettering method for a silicon slice, which comprises the following steps of: preparing a boron-doped aluminum source, cleaning the silicon slice, forming a boron aluminum layer on the surface of the silicon slice by using screen printing or spin coating technology, performing annealing with one or more steps, and removing the surface layer of the silicon slice. The boron is doped into the aluminum by using the characteristic that the boron has high solid solubility in silicon compared with the aluminum, and the boron is doped into a heavy doped layer on the back of the silicon by using an alloying process of the aluminum and the silicon to obtain an aluminum-boron common gettering layer with high doping concentration. The aluminum-boron common gettering method can form a deeper and uniform gettering layer with higher doping concentration at the same annealing temperature, achieve the gettering effect of other processes at a low temperature, and reduce the influence of high temperature on the performance of the silicon slice. The aluminum-boron common gettering method has the characteristics of low cost, easy operation and good gettering effect, and has great application prospect.

Description

technical field [0001] The invention belongs to the field of integrated circuits and solar energy applications, in particular to a method for co-absorbing aluminum and boron on a silicon wafer. Background technique [0002] With the development of integrated circuit technology, its line width has gradually decreased from hundreds of nanometers to about 30 nanometers, and it is likely to follow Moore's law for further reduction. Therefore, the device has higher and higher quality requirements for the clean area on the surface of the silicon wafer. A general integrated circuit level silicon wafer will form a large amount of oxygen precipitation in the silicon wafer, and use the oxygen precipitation as a gettering center to bind metal impurities around it to form a clean area on the surface. However, this gettering method is only available when the concentration of metal impurities is high (>10 13 atoms / cm 3 ) is more effective; and when the concentration of metal impurit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L31/18
CPCY02P70/50
Inventor 杨德仁顾鑫樊瑞新余学功
Owner ZHEJIANG UNIV
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