Boron and aluminum common gettering method for silicon wafer

A boron-aluminum and silicon wafer technology, applied in the field of aluminum-boron co-gettering of silicon wafers, to achieve the effects of low energy consumption, low secondary pollution, and uniform gettering layer

Active Publication Date: 2012-05-09
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

[0032] (1) 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 water (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;

[0033] (2) The boron-aluminum target is made of boron-doped aluminum according to the conventional method, and the mass fraction of boron in the boron-aluminum target is 2.5%;

[0034] (3) Utilize the boron-aluminum target material in (2) to form the boron-aluminum layer with a thickness of 8 μm respectively on both sides of the silicon chip by sputtering, a...

Embodiment 2

[0042] (1) 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 water (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;

[0043] (2) making a boron-aluminum mixture with boron-doped aluminum, the mass fraction of boron element in the boron-aluminum mixture is 2%;

[0044] (3) Utilizing the boron-aluminum mixture in (2) to form a boron-aluminum layer with a thickness of 10 μm respectively on both sides of the silicon wafer by thermal evaporation method, the mass fraction of boro...

Embodiment 3

[0049] Same as embodiment 1, its difference is only: heat treatment takes rapid heat treatment, that is, step (4) is:

[0050] The silicon wafer obtained in step (3) is placed in a rapid heat treatment furnace under the protection of clean and dry air and heated at 900° C. for 3 minutes, and the silicon wafer is rapidly cooled.

[0051] The sample that this embodiment makes is carried out performance test, and test condition is the same as embodiment 1, and test result is: the metal impurity content before test is 5.5 * 10 13 atoms / cm 3 ; After the test, the metal impurity content is 7.5×10 12 atoms / cm 3 .

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Abstract

The invention discloses an aluminum and boron common gettering method for a silicon wafer, which comprises the following steps of: preparing a boron-doped aluminum source; cleaning a silicon wafer; forming a boron-aluminum layer on the surface of the silicon wafer by utilizing a film plating technology; annealing at one step or multiple steps; and removing the surface layer of the silicon wafer. The invention utilizes the characteristic that the boron has higher solid solubility in silicon relative to aluminum, dopes the boron into the aluminum and dopes the boron into a heavy doped layer in the alloying process of the aluminum and silicon to obtain an aluminum-boron common gettering layer with high doping concentration. The aluminum and boron common gettering method of the invention can form the gettering layer which is deeper and even and has higher doping concentration at same annealing temperature and achieve the gettering effect of other processes at lower temperature and reduce the influence of high temperature on the performance of the silicon wafer. The aluminum and boron common getteirng method of the invention has the characteristics of low cost, easy operation and good gettering effect and has wider 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 chip. 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 impuriti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01L31/18
CPCY02P70/50
Inventor 杨德仁樊瑞新顾鑫余学功
Owner ZHEJIANG UNIV
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