TW510924B - Surface cleaning method of sputtering target - Google Patents

Abstract

This invention relates to one type of sputtering target and its surface cleaning method, suitable for a sputtering apparatus. The method includes following steps: using the sputtering apparatus to perform a first stage sputtering process and using a first reaction gas to perform ion bombardment on the surface of the sputtering target for a first period of time; and using the sputtering apparatus to perform a second stage sputtering process and using a second reaction gas to perform ion bombardment on the surface of the sputtering target for a second period of time so that the surface of the sputtering target is cleaned, in which the kinetic energy, the atomic radius and the atomic weight of the first reaction gas are greater than the kinetic energy, the atomic radius and the atomic weight of the second reaction gas.

Description

510924 V. Description of the Invention (i) Field of the Invention This case is a money boat and its surface cleaning method, especially a sputtering target and its surface cleaning method suitable for a sputtering equipment. BACKGROUND OF THE INVENTION In the semiconductor manufacturing process or the manufacturing process of thin film transistor panels, Physical Vapor Deposition (PVD) is a commonly used thin film deposition technology, and physical vapor deposition can be mainly divided into evaporation ( Evaporation and sputtering. Please refer to the first figure, which is a common metal sputtering equipment, which mainly uses the ions generated by the reactive gas plasma to bombard the metal stem 10, so that there is a metal target in the gas phase of the plasma. Particles (such as atoms), and finally a metal thin film is formed on the substrate 11. However, when the above-mentioned sputtering equipment is in the standby time for too long (for example, entering the standby time exceeds eight hours) or the particle contamination in the reaction chamber 12 is too serious, the operator needs to formally carry out the money-spattering process. A "pre-sputter" process is performed first to remove impurities, oxides, and nodule that may be attached to the surface of the metal target 10, which may affect the quality of the sputter deposition. The "pre-sputter" procedure used today only takes the first few substrates (or wafers) entering the reaction chamber 12 as victims, and uses a single reaction gas process that is longer than the standard process time. On these substrates (or crystals

Page 4 510924 V. Description of the invention (2) Circle) Sputtering is performed to remove foreign matter that may be attached to the surface of the metal target 10, but this method cannot effectively remove the surface of the metal target 10 and control the metal target 10. The roughness of the surface is the main purpose of developing this case in order to improve the lack of the above-mentioned conventional means. SUMMARY OF THE INVENTION The present invention is a method for cleaning the surface of a sputtering target, which is applicable to a sputtering device. The method includes the following steps: the sputtering device is subjected to a first-stage sputtering process, and the sputtering is performed with a first reaction gas; The target surface is subjected to ion bombardment for a first time; and the base plating equipment is subjected to a second-stage base plating process, and the target surface is ion bombarded with a second reaction gas for a second time, and then cleaned. On the surface of the sputtering target, the kinetic energy of the first reaction gas is greater than the kinetic energy of the second reaction gas. Another aspect of the case is a method for cleaning the surface of a sputtering target, which is applicable to a sputtering equipment. The method includes the following steps: the sputtering equipment is subjected to a first-stage sputtering process, and a first reaction gas is used to The surface of the sputtering target is subjected to ion bombardment for a first time; the sputtering equipment is subjected to a second-stage sputtering process, and the surface of the sputtering target is subjected to ion bombardment with a second reaction gas for a second time, and then The surface of the sputtering target is cleaned, wherein the atomic radius and atomic weight of the first reaction gas are larger than the atomic radius and atomic weight of the second reaction gas. Another aspect of the present case is a sputtering target, which is suitable for a sputtering device, and the sputtering target is treated by the following cleaning method: the sputtering device

Page 5 510924 5. Description of the invention (3) Perform a first-stage sputtering process to ion bombard the dry surface of the coin with a first reaction gas for a first time; and make the sputtering equipment perform a first In a two-stage sputtering process, a second reaction gas is used to ion bombard the surface of the sputtering target for a second time, and then the surface of the sputtering target is cleaned. The kinetic energy of the first reaction gas is greater than that of the second reaction gas. Kinetic energy. According to the above-mentioned concept, in the method of cleaning the surface of a sputtering target, the material of the sputtering target is a conductor. The material of the sputtering target in the method of cleaning the surface of the sputtering target The reaction gas in the method of cleaning the surface of the sputtering target The material of the sputtering target in the method of cleaning the surface of the sputtering target is a metal according to the above concept. According to the above concept, it is an inert gas. According to the above idea, the substance is tungsten molybdenum. According to the above concept, in the method for cleaning the surface of a sputtering target, the first reaction gas system is krypton (Kr), and the second reaction gas system is argon (Ar). According to the above concept, in the method for cleaning the surface of a sputtering target, the length of the first time accounts for 50% to 80 ° / of the first time plus the second time. , And the length of the second time accounts for 50% to 20% of the first time plus the second time length. According to the above-mentioned concept, the flow rate of the krypton (Kr) in the sputtering target surface cleaning method is between 2 0 seem and 30 0 sccm, and the flow rate of the argon (Ar) is between 30 sccm and 8 0 s c cm. According to the above concept, the flow rate of the krypton (κ Γ) in the sputtering target surface cleaning method is 240 sccm, and the flow rate of the argon (Ar) is 50 sccm.

Page 6 510924 5. Description of the invention (4) Simple diagram description The following diagram and detailed description can be used to gain a deeper understanding: The first picture: it is a common metal coin plating (sputtering) equipment schematic diagram. The second picture: It is not intended to use the metal sputtering equipment on this case. The elements included in the drawings of this case are listed as follows: metal target 10 substrate 11 reaction chamber 12 sputtering target 20 substrate (or wafer) 2 2 reaction chamber 2 1 The preferred embodiment is described to solve the above-mentioned shortcomings in conventional technology. This case discloses a cleaning method for the surface of a sputtering target, which is applicable to the pre-sputter procedure of sputtering equipment. The sputtering equipment mainly includes a sputter ore 20 and a reaction chamber 21 for A thin film is formed on the substrate (or wafer) 2 (see the second figure). However, when the above-mentioned sputtering equipment is in the standby time for too long (for example, entering the standby time for more than eight hours) or the particle is contaminated in the reaction chamber 21

Page 7 510924 5. Description of the invention (5) When the situation is too serious, the operator can perform the method for cleaning the surface of the sputtering target disclosed in this case, and then remove the impurities and oxidation that may be attached to the surface of the sputtering target 20 Foreign matter and nodule may affect the quality of sputter deposition. The method in this case mainly includes the following steps: (1) subjecting the sputtering equipment to a first-stage sputtering process, wherein an ion bombardment is performed on the surface of the sputter bond stem 20 with a first reaction gas for a first time *, (2) The sputtering equipment is subjected to a second-stage sputtering process, in which a surface of the sputtering target 20 is subjected to ion bombardment with a second reaction gas for a first and second time, and the kinetic energy of the first reaction gas is The atomic radius and atomic weight are greater than the kinetic energy, atomic radius and atomic weight of the second reaction gas. The material of the sputtering target 20 may be a conductor, usually a metal. The reaction gas _ is an inert gas, which can be mainly an inert gas (such as krypton (Kr), argon (Ar)) or nitrogen. An example is described below, in which the material of the sputtering target 20 is molybdenum

Iron (MoW 'in which the atomic proportion' Mo accounts for 65% 'and w accounts for 35%), and today the first reaction gas and the second reaction gas are krypton (Kr) and nitrogen, respectively. Basic information about molybdenum (M), tungsten (W), krypton (Kr), and argon (Ar) is as follows: the atomic weights of molybdenum (M), tungsten (W), krypton (Kr), and argon (ΑΓ) are 95.94, 1 83.85, 83. 80, and 3 9. 9 5. The equivalent molecular weight of tungsten molybdenum (Mww) knives is 126.706. As for the krypton (Kr) and argon (Ar) atomic half furnaces, they are 112XE (-12) meters and 98χΕ (_12) meters, respectively. According to the following data, a calculation and derivation shows that the collision probability ratio (meaning the effective collision area ratio) between argon (Ar) and atmosphere (I) is the square ratio of the atomic radius. (9 8/1 1 2) 2 = 76 · 6% (assuming that the atom is approximately glassy ^ ▲ P 4 is bad). While in elastic collision

510924 V. Description of the invention (6) Under the assumption that the free charge and the electric field are the same, the effective collision kinetic energy ratio of argon (A r) and krypton (K r) is ((4X 126. 706X 39.95) / (39.95 + 126 70 6) 2) / ((4x 126. 706X83. 80) / (83-80 + 126. 706) 2) = 76.1%. It can be seen that argon (Ar) is less than krypton (Kr) in terms of collision probability or effective kinetic energy. Therefore, the deposition rate of sputtering film using argon (Ar) as the reaction gas will be less than that of krypton (Kr). For the deposition rate of the sputtered film of the reactive gas, on the other hand, under the impact of argon (Ar), the surface uniformity of the sputtering target completed with tungsten molybdenum will be more uniform than that of the sputtering target under the impact of krypton (Kr) Degree is better. In this case, argon (Ar) gas with a flow rate of 20 seem to 240 scm (preferably 240 seem) and argon (Ar flow rate of 30 seem to 80 sccm (preferably 50 sccm)) ) Gas to perform ion bombardment on the surface of the sputtering target 20 for a first time and a second time, wherein the length of the first time accounts for 50% to 80% of the first time plus the second time, and The length of the second time accounts for 50% to 20% of the first time plus the second time. Because the kinetic energy and particles of krypton (Kr) gas are larger, the bombardment effect is better. Therefore, the speed of removing foreign matter on the surface of the sputtering target 20 is faster, and although the kinetic energy and particles of argon (A r) carcass are small, However, it can reduce the rough bond on the surface of ytterbium plating and effectively repair the rough surface caused by ion bombardment in the previous stage. In order to verify that this case can indeed improve the lack of conventional methods, we conducted an experiment. After the sputtering equipment has been in standby for 24 hours, I will perform a customary pre-mine process. After the first 6 substrates (or wafers) are used as sacrifices and the customary pre-sputtering process is completed, the serial number will be 7 , 8, 9, 1 〇, 11, 1 2

Μ Page 9 510924

V. Description of the invention The tungsten molybdenum tungsten plating with a thickness of 235 angstroms is performed on the 6 substrates (or wafers) underneath. Then, after waiting for 24 hours, perform the pre-sputtering procedure disclosed in the example of this case. After the first 6 substrates (or wafers) are sacrificed and the pre-hidden plating procedure disclosed in the example is completed, Tungsten molybdenum tungsten sputtering with a thickness of 2 3 50 angstroms is also performed on 6 substrates (or wafers) numbered 19, 20, 21, 22, 23, and 24. The number of particles measured in the above sputtering process is described in the following table: Number of substrates in the reaction chamber total number of particles 94 Sputtering target table 8.90 / 〇 substrate number 19__ 〇A Total number of particles in the reaction chamber 92_ 97 87 99 ^ --- Sputtering target table 8 112! 〇.0% 9.4% Q / ς〇 / 9 78 9.3〇 / 〇v / 21__ 22 10 _ 132 9.7% 11 127 1 丨 — '_ ο π 23 101 y · 〇 / 〇9.5 % 12 〇y 1 Λ C, 9.4% 24 88 9.2% ～ average 105.3 9 ^ 58% ^ average 94 923% ^ -----

From the above table < it is clear that the method in this case is an effective

510924 V. Description of the invention (8) The improvement rate of the total number of particles and the uniformity of the sputtering target surface are 10.73% and 3.65%, which effectively improves the lack of customary methods and thus achieves the main purpose of developing this case. purpose. And this case can be applied to the manufacturing process of integrated circuit or thin-film transistor liquid crystal display according to demand. Therefore, the invention of this case can be modified by people skilled in this technology as any craftsman. The scope wants to protect. Page 11 510924 Brief description of the diagram The first picture: It is a schematic diagram of the common metal sputtering equipment. The second picture: it is a schematic diagram of the metal sputtering equipment used in this case.

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Claims (1)

510924p______ _I ά: I_______________ VI. 1. A method for cleaning the surface of a sputtering target, which is suitable for use on a sputtering equipment. The method includes the following steps: The sputtering equipment is subjected to a first-stage sputtering process with a first reaction gas. Performing ion bombardment on the surface of the sputtering target for a first time; and performing a second-stage sputtering process on the sputtering equipment to perform ion bombardment on the surface of the sputtering target with a second reaction gas for a second time And further clean the surface of the sputtering target, wherein the kinetic energy of the first reaction gas is greater than the kinetic energy of the second reaction gas. 2. The method for cleaning the surface of a sputtering target as described in item 1 of the scope of patent application, wherein the material of the sputtering target is a conductor. 3. The method for cleaning the surface of a sputtering target as described in item 2 of the scope of patent application, wherein the material of the sputtering target is metal. 4. The method for cleaning the surface of a sputtering target as described in item 1 of the scope of the patent application, wherein the reaction gas system is an inert gas. 5. The method for cleaning the surface of a sputtered target as described in item 1 of the scope of patent application, wherein the dried material is keyed iron. 6. The method for cleaning the surface of a sputtering target according to item 5 of the scope of the patent application, wherein the first reaction gas system is krypton (Kr) and the second reaction gas system is argon (Ar). 7. The method for cleaning the surface of a sputtering target according to item 6 of the scope of patent application, wherein the length of the first time accounts for 50% to 80% of the first time plus the second time, and the length of the second time 50% to 20% of the first time plus the second time length. 8 · The method for cleaning the surface of a sputtering target as described in item 6 of the scope of patent application, which Page 13 510924 6. In the scope of patent application, the flow rate of the krypton (Kr) is between 200 seem and 300 sccm, and the flow rate of the argon (Ar) is between 30 s c cm and 80 s c cm. 9. The method for cleaning the surface of a sputtering target according to item 8 in the scope of the patent application, wherein the flow rate of the krypton (Kr) is 240 sccm, and the flow rate of the argon (Ar) is 5 Oseem 〇 1 0. The method for cleaning the surface of a sputtering target according to item 1, wherein the atomic radius and atomic weight of the first reaction gas are larger than the atomic radius and atomic weight of the second reaction gas. 11. A method for cleaning the surface of a sputtering target, which is applicable to a sputtering device, the method includes the following steps: the sputtering device is subjected to a first-stage sputtering process, and the surface of the sputtering target is reacted with a first reaction gas; Performing ion bombardment for a first time; and performing a second-stage sputtering process on the sputtering equipment, performing ion bombardment of the coin key dry surface with a second reaction gas for a second time, and then cleaning the sputtering The target surface is plated, wherein the atomic radius and atomic weight of the first reaction gas are larger than the atomic radius and atomic weight of the second reaction gas. 1 2. The method for cleaning the surface of a sputtering target according to item 11 of the scope of patent application, wherein the material of the sputtering target is a conductor. 13. The method for cleaning the surface of a sputtering target according to item 11 of the scope of patent application, wherein the dry material of the sputtering is metal. 14 · The method for cleaning the surface of a sputtering target as described in item 11 of the scope of patent application, wherein the reaction gas system is an inert gas. 15 · The method for cleaning the surface of a sputtering target according to item 11 of the scope of patent application, wherein the material of the sputtering target is tungsten molybdenum. Page 14 510924 6. Application patent scope 1 6. The method for cleaning the sputtering target surface as described in item 15 of the patent application scope, wherein the first reaction gas system is krypton (Kr) and the second reaction gas system is Argon (Ar). 1 7. The method for cleaning the surface of a sputtering target according to item 16 of the scope of patent application, wherein the length of the first time accounts for 50% to 80% of the first time plus the second time length, and the second time The length of time accounts for 50% to 20% of the first time plus the second time. 1 8. A sputtering target suitable for a sputtering device, the sputtering target is processed through the following steps: The sputtering device is subjected to a first-stage sputtering process, and the sputtering is performed with a first reaction gas. The target surface is subjected to ion bombardment for a first time; and the sputtering equipment is subjected to a second-stage sputtering process, and the target surface is subjected to ion bombardment with a second reaction gas for a second time, and then cleaned. On the surface of the sputtering target, the kinetic energy of the first reaction gas is greater than the kinetic energy of the second reaction gas. 19. The sputtering target according to item 1 of the scope of patent application, wherein the material of the sputtering target is a conductor. 20. The sputtering target according to item 19 of the scope of patent application, wherein the sputtering target is made of metal. 2 1. The sputtering target as described in item 18 of the scope of patent application, wherein the reaction gas system is an inert gas. 2 2 · The sputtering target as described in item 18 of the scope of the patent application, wherein the material of the sputtering target is keyed hafnium. 23. The sputtering target as described in item 22 of the scope of patent application, wherein the first Page 15 510924 6. Scope of patent application The reaction gas system is krypton (Kr), and the second reaction gas system is argon (Ar). 24. The sputtering target as described in item 23 of the scope of patent application, wherein the length of the first time accounts for 50% to 80% of the first time plus the second time, and the length of the second time accounts for the first Time plus 50% of the second time length to 20/20 ° 25. The sputtering target as described in item 23 of the scope of patent application, wherein the flow rate of the krypton (Kr) is 2 0 sccm to 3 0 0 Between sccm, the flow rate of the argon (A r) is between 30 seem and 8 Osccm. 26. The sputtering target as described in item 25 of the scope of patent application, wherein the flow rate of the krypton (Kr) is 24 0 s c c m, and the flow rate of the argon (A r) is 50 0 s c c m. 27. The sputtering target as described in item 18 of the scope of the patent application, wherein the atomic radius and atomic weight of the first reaction gas are larger than the atomic radius and atomic weight of the second reaction gas. Page 16