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Annealing method of tungsten disilicide 

Release time :2022/11/28

(19) State Intellectual Property Office of the People's Republic of China


(12) Application for invention patent



(21) Application No.: 201010605215.8


(22) Application date: December 27, 2010



(71) Applicant Wuxi China Resources Shanghua Semiconductor Co., Ltd



Address 214028 National High tech Industry, Wuxi, Jiangsu Province



No. 5, Hanjiang Road, Industrial Development Zone



(72) Inventor: Zhang Huawei, Sun Xiaofeng, Gao Yongliang



(51)Int.Cl.



C01B 33/06 (2006.01)




*CN102530955A*



(10) Application Publication No.: CN 102530955 A



(43) Publication date of application: July 4, 2012



(54) Title of the invention


Annealing method of tungsten disilicide



(57) Summary




Text box: CN 102530955 A The invention provides a method for annealing tungsten disilicide, which includes the following steps: annealing, and controlling the temperature of entering the boat to be lower than 600 ℃. Compared with the prior art, the invention has the beneficial effect of changing the stripping phenomenon of the tungsten disilicide film caused by thermal stress, and fundamentally eliminating the influence of the film stripping on the device.



1. An annealing method of tungsten disilicide, which is characterized in that it includes the following steps: annealing, and controlling the temperature of entering the boat below 600 ℃.




2. The tungsten disilicide annealing method according to claim 1, which is characterized in that before annealing WSi2, it includes the following steps:




Tungsten disilicide was first deposited by LPCVD method, and its x value was 2.6 ~ 2.8; After the first annealing, the x value is reduced to 2.2~2.3, and tungsten disilicide is obtained.




3. The tungsten disilicide annealing method according to claim 2, which is characterized in that when the x value is 2.6~2.8, the resistivity is 700~900 μ Ω·cm。




4. The tungsten disilicide annealing method according to claim 2, which is characterized in that when x value is 2.2~2.3, the resistivity is less than 70 μ Ω·cm。




5. The tungsten disilicide annealing method according to claim 1, which is characterized in that the annealing is completed in the furnace tube.



Annealing method of tungsten disilicide



[Technical field]



[0001] The invention relates to an annealing method of tungsten disilicide, in particular to an annealing method which can eliminate the stripping of tungsten disilicide films.



[Background Technology]



[0002] Because of its high melting point, good stability and low resistivity, tungsten disilicide (WSi2) has become more and more widely used in the CMOS process, mainly used to improve the ohmic contact between metal aluminum and silicon, and used together with polysilicon as the conductive material of gate to reduce the resistivity of gate.




[0003] At present, it is common to deposit tungsten disilicide by LPCVD method. Its x value is about 2.6~2.8. At this time, the resistivity is still high, about 700~900 μ Ω · cm, the resistivity can be reduced to 70 only after another annealing μ Below Ω · cm, the x value is 2.2~2.3, which plays a role in reducing the resistivity of polysilicon.



[0004] In the semiconductor manufacturing process, tungsten disilicide will undergo multi-channel annealing, and the lattice damaged by ion implantation will be repaired through the high-temperature process of annealing, so as to activate doping, and then the device can be formed. Therefore, the later annealing is crucial to the device, and the temperature and time of its thermal process cannot be changed at will. As the annealing needs to be completed in the furnace tube, the boat inlet temperature is generally above 700 ℃, and the standard boat inlet temperature of the company is about 750 ℃. However, the thermal stress generated by such a thermal process may cause the peeling of the film, such as the peeling of tungsten disilicide, so as to affect the device.




[Contents of the Invention]




[0005] In view of the shortcomings of the prior art, the technical problem solved by the invention is to provide a tungsten disilicide annealing method that can eliminate film peeling.




[0006]


The purpose of the invention is achieved by providing the following technical solutions:




[0007]


The invention relates to a tungsten disilicide annealing method, which comprises the following steps:




[0008]


Annealing, and control the boat inlet temperature below 600 ℃.




[0009]


Optionally, before annealing tungsten disilicide, the following steps are included:




[0010]


Tungsten disilicide was first deposited by LPCVD method, and its x value was 2.6 ~ 2.8;




[0011]


After the first annealing, the x value is reduced to 2.2~2.3, and tungsten disilicide is obtained.



[0012]


Optionally, when x value is 2.6~2.8, the resistivity is 700~900 μ Ω·cm。




[0013]


Optionally, when x value is 2.2~2.3, the resistivity is less than 70 μ Ω·cm。




[0014]


Optionally, the annealing is completed in the furnace tube.




[0015]


Compared with the prior art, the invention has the beneficial effect of changing the stripping of tungsten disilicide film caused by thermal stress




Phenomenon, fundamentally eliminating the impact of film peeling on devices.


[Specific embodiment]




[0016] The following is the best embodiment of the invention.



[0017] Annealing is a metal heat treatment process that slowly heats the metal to a certain temperature, maintains it for a sufficient time, and then cools it at an appropriate rate (usually slow cooling, sometimes controlled cooling).



[0018] It is used to soften materials or workpieces after casting, forging, rolling, welding or cutting, improve plasticity and toughness, homogenize chemical composition, remove residual stress, or obtain expected physical properties. Annealing processes vary with different purposes, such as recrystallization annealing, isothermal annealing, homogenization annealing, spheroidizing annealing, stress relief annealing, recrystallization annealing, stabilization annealing, magnetic field annealing, etc.



[0019] The purpose of general returns is to:



[0020] (1) Reduce hardness and improve machinability;



[0021] (2) Eliminate residual stress, stabilize size, and reduce deformation and crack tendency;



[0022] (3) Refine the grain, adjust the structure and eliminate the structural defects.



[0023] Annealing process is widely used in production. According to different purposes of workpiece annealing, there are many kinds of annealing process specifications, including complete annealing, spheroidizing annealing, and stress relief annealing.




[0024] The tungsten disilicide annealing method of the present invention reduces the thermal budget in the annealing process, thereby eliminating the possibility of film peeling caused by thermal stress.




[0025] The present invention includes the following steps before annealing tungsten disilicide:




[0026] First of all, tungsten disilicide is formed by LPCVD method. Its x value is about 2.6~2.8. At this time, the resistivity is still high, about 700~900 μ Ω·cm ;




[0027] After the first annealing, the resistivity is reduced to 70 μ Below Ω · cm, the x value is 2.2~2.3, which plays a role in reducing the resistivity of polysilicon and getting tungsten disilicide.




[0028] At this time, the tungsten disilicide generated from tungsten disilicide can be subsequently annealed:




[0029] Subsequent annealing needs to be completed in the furnace tube, and the boat inlet temperature is generally lower than 600 ℃.




[0030] Through experiments, it is known that for the same process time and temperature, only changing the boat inlet temperature and controlling the boat inlet temperature below 600 ℃ can avoid film peeling. The invention overcomes the peeling phenomenon of the tungsten disilicide film caused by the traditional concept that the boat entering temperature is above 700 ℃ in the prior art.




[0031] By means of low-temperature boat entry, the phenomenon of tungsten disilicide film peeling caused by thermal stress is changed, and the influence of film peeling on devices is fundamentally eliminated.




[0032] Although the preferred embodiments of the invention have been disclosed for example purposes, those skilled in the art will realize that various improvements, additions and substitutions are possible without departing from the scope and spirit of the invention disclosed by the appended claims.