TW201343329A - Method for increasing sputtering rate of metal target - Google Patents

Abstract

A method for increasing a sputtering rate of a metal target is described, which includes the following steps. A metal target is provided, wherein a surface of the metal target processed by a milling treatment has a strained layer, and the milling treatment has a spindle speed and a feed rate. A polishing step is performed on the strained layer to thin the strained layer, wherein both the spindle speed and the feed rate are positively correlated to a polishing depth of the polishing step.

Description

Method for increasing the sputtering rate of a metal target

This invention relates to a metal target, and more particularly to a method of increasing the sputtering rate of a metal target.

With the development of the technology industry, the sputtering process has been widely used in the manufacture of various products, such as LCD, hard disk, solar cells and so on.

In general, the target used in the sputtering process, in addition to affecting the rate of sputtering, also affects the quality of the film produced by sputtering. For example, the metal target used in the production of the LCD must be subjected to cutting, surface processing, etc. after the initial embossing, in order to conform to the shape of the target required for the sputtering machine of each generation panel.

However, after the processed target, the sputtering rate at the initial stage of sputtering (ie, the surface of the target) is lower than the sputtering rate after the initial sputtering (ie, the internal quality of the target). The sputtering rate of the surface of the target is lower than the sputtering rate of the internal material of the target, which will result in a high resistance value of the film of the LCD panel produced per unit time. Therefore, the current panel manufacturers mostly solve the problem of poor sputtering quality on the surface of the target by washing the target (ie, pre-sputtering).

However, this washing process usually requires about 5 to 10 batches, and a total loss of about 120 to 240 glass substrates is required to solve the problem that the resistance value of the film of the aforementioned LCD panel is high. Such a large number of target washing batches not only reduces the target utilization rate, but also increases the manufacturing cost of the panel.

There are currently three methods for increasing the target sputtering rate, which are disclosed in the following three documents. The first document was published in 1956 by Gottfried K. Wehner in the journal Physical Review, Vol. 102, p. 690. The second document was published by H. Tsuge and S. Esho in the Journal of Applied Physics, Vol. 52, page 4391, 1981. The third document is U.S. Patent No. 5,427,732. The first method is mainly to increase the sputtering rate by controlling the grain size. In general, the finer the grains, the more grain boundaries and the higher the sputtering rate. The second method is mainly to increase the sputtering rate by controlling the aggregate structure or atomic bulk density of the sputter surface. Generally, the higher the atomic bulk density of the sputtered surface, the greater the chance of being sputtered and the higher the sputtering rate. The third method is mainly to increase the atomic kinetic energy of the target by applying energy to the sputtering atom on the surface of the target, thereby increasing the ability of the atom to detach from the surface of the target, thereby achieving the purpose of increasing the sputtering rate.

However, the first method and the second method described above have problems in that the rolling temperature, the amount of reduction, and the reduction of the metal target in the rolling process have determined the microstructure of the target and the overall target (surface addition). Sputter rate of the upper end. However, the main cause of the sputtering rate of the target surface is lower than the sputtering rate of the target material. After the target rolling is completed, the residual stress and strain layer generated by the processing of the target surface will cause the target surface. The sputtering rate is low. Therefore, it is impossible to solve the problem that the sputtering rate of the target surface is low and the number of washing targets is large, because the target microstructure control is not effectively removed, and the surface strain layer of the target is not effectively removed.

The problem with the third method is that although the atomic kinetic energy of the target is increased by heating or vibration to increase the probability of the atom leaving the surface of the target, or the surface stress of the target is released by heat treatment or wave oscillation of the target. The method can improve the quality of the target surface. However, these methods will destroy the microstructure of the target internal matter, but affect the overall sputtering performance of the target.

Therefore, an aspect of the present invention is to provide a method for increasing the sputtering rate of a metal target, which is mainly for grinding a strain layer generated on a surface of a metal target by a milling machine to thin the strain. Layer thickness and reduce stress on the surface of the metal target. Therefore, the sputtering rate of the surface of the metal target can be increased and the batch washing target can be reduced without destroying the texture characteristics of the internal material of the metal target. Moreover, this additional grinding treatment can also improve the smoothness and flatness of the surface of the metal target, and increase the visual perception.

In accordance with the above objects of the present invention, a method of increasing the sputtering rate of a metal target is provided, which comprises the following steps. A metal target is provided in which the surface of the metal target is subjected to a milling process to have a strained layer, and the milling process has a milling speed and a feed speed. The strain layer is subjected to a grinding step to thin the strained layer, wherein the grinding depth of the grinding step is positively correlated with the milling speed and the feed speed.

According to an embodiment of the present invention, the grinding step is performed by using the abrasive paper, and the number of the abrasive paper is from 400 to 800.

According to another embodiment of the present invention, the milling machine has a rotational speed of 1592 rpm, an infeed speed of 318 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.3 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 398 rpm, an infeed speed of 224 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.15 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 796 rpm, an infeed speed of 224 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.2 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 4500 rpm, an infeed speed of 900 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.5 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 4500 rpm, an infeed speed of 2250 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.55 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 1592 rpm, a feed rate of 318 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.2 mm.

According to still another embodiment of the present invention, the milling machine has a rotational speed of 1592 rpm, an infeed speed of 318 mm/min, a grinding sandpaper number of 400, and a grinding depth of 0.4 mm.

According to still another embodiment of the present invention, the metal target has a purity of from 3N to 6N.

Please refer to Fig. 1, Fig. 2A and Fig. 2B. 1 is a flow chart showing a method of increasing the sputtering rate of a metal target according to an embodiment of the present invention. Figure 2A is a schematic diagram showing a metal target that has not been processed by a milling machine. Figure 2B is a schematic view showing that the surface of the metal target is not ground after being processed by a milling machine. In general, in the processing of the metal target 204, the surface 202 of the metal substrate 200 needs to be subjected to a milling process. As shown in FIG. 2B, after the metal target 204 is processed by the milling machine, a strained layer 206 is generated on the surface of the metal target 204. At the same time, the milling process also increases the residual stress on the surface of the metal target 204, so that the sputtering rate of the target surface 204 is lowered and a large number of wash targets are caused.

Therefore, in the present embodiment, when the method 100 of increasing the sputtering rate of the metal target is performed, as described in step 102, the metal target 204 is first provided. As shown in FIG. 2B, the surface of the metal target 204 has a strained layer 206 through a milling process. The metal target 204 can be, for example, an aluminum target having a purity of 3N to 6N.

Next, as described in step 104, the strained layer 206 of the metal target 204 is ground to thin the strained layer 206 of the metal target 204.

Please refer to FIG. 2C and FIG. 2D , wherein the 2C and 2D drawings respectively show the surface of the metal target after being processed by a milling machine and then ground at a grinding depth of 0.1 mm and 0.5 mm. As can be seen from these figures, the above-mentioned grinding depth refers to the thickness of the metal target which is abraded in the grinding step.

Further, in the present embodiment, the polishing step may be performed using abrasive sandpaper. In general, if the abrasive paper is too thick, it is likely that the surface of the metal target 204 is too rough, but too thin, and the grinding time is too long. Therefore, in some embodiments, the number of abrasive papers used is from 400 to 800.

It is worth mentioning that the method 100 for improving the sputtering rate of a metal target of the present invention can be applied to various targets of current target manufacturers, such as metal targets for LCDs, magnetic targets for hard disks, and solar cells. A transparent conductive oxide (TCO) target or the like.

Please refer to Table 1, which records the residual stress, grain size, sputtering rate and the required wash target batch of the aluminum target after the 5N aluminum target is processed under different processing conditions.

If the value of the residual stress is negative, it means that the residual stress is compressive stress. On the other hand, if the value of the residual stress is positive, it means that the residual stress is the tensile pressure. In addition, the residual stress can be measured by X-ray diffraction analyzer (XRD), and the residual stress in Table 1 is obtained by the D8 advance X-ray diffraction analyzer provided by Bruker. Measured.

It can be seen from Table 1 that the surface of the aluminum target after rolling is milled under the processing conditions of milling machine speed (S) of 1592 rpm and milling machine feed rate (F) of 318 mm/min, and no grinding is applied ( That is, the grinding depth is 0). A large amount of residual compressive stress of about -0.40 kg/mm ² will exist on the surface of the aluminum target, so that the sputtering rate of the surface of the aluminum target is only 27 /s, resulting in a large number of wash target batches of 10 times.

However, as can be seen from Table 1, after the milling machine is processed, the surface of the aluminum target is ground with a No. 400 abrasive paper. As the depth of the grinding increases, the residual stress on the surface of the aluminum target is gradually reduced, so that the sputtering rate on the surface of the aluminum target can be increased, thereby greatly reducing the batch washing target. In addition, target utilization will increase. However, it can be observed from Table 1 that if the grinding depth is too large, the residual stress on the surface of the aluminum target will change from compressive stress to tensile stress, which will reduce the sputtering rate and increase the number of washing targets, which is not conducive to the target. Quality.

Further, as can be seen from Table 1, in one embodiment, the milling machine has a rotational speed of 1592 rpm, the milling machine has a feed speed of 318 mm/min, the abrasive sandpaper has a number of 400, and the grinding depth is 0.3 mm. The residual stress on the surface of the aluminum target can be reduced to 0.02 kg/mm ² , and has 30 The maximum sputtering rate of /s, and only one wash batch is required.

In another embodiment, the milling machine has a rotational speed of 1592 rpm, the milling machine has a feed rate of 318 mm/min, the abrasive sandpaper has a number of 400, and the grinding depth is 0.2 mm. The residual stress on the surface of this aluminum target can be reduced to -0.13kg/mm ² with 28.5 /s maximum sputter rate and 3 wash target batches.

In yet another embodiment, the milling machine has a rotational speed of 1592 rpm, the milling machine has a feed rate of 318 mm/min, the abrasive sandpaper has a number of 400, and the grinding depth is 0.4 mm. The residual stress on the surface of this aluminum target can be reduced to 0.19kg/mm ² with 27.6 /s maximum sputter rate and 3 wash target batches.

On the other hand, different milling machine processing conditions, the required grinding depth is also different. Please refer to Table 2, which records various milling machine processing conditions, grinding depth and washing target batch.

It can be seen from Table 2 that after the surface of the metal target after rolling is milled under various processing conditions, it needs to be ground with different grinding depths to reduce the number of times of washing the metal target to one time.

In other words, in one embodiment, the milling machine was milled at a milling speed of 398 rpm and an infeed speed of 224 mm/min, and the surface of the metal target was ground to a depth of 0.15 mm using a No. 400 abrasive paper. In another embodiment, the milling machine is milled at a milling speed of 796 rpm and a feed rate of 224 mm/min, and the surface of the metal target is ground to a depth of 0.2 mm using a 400 grit sandpaper. In still another embodiment, the milling machine is milled at a mill speed of 1592 rpm and a feed rate of 318 mm/min, and the surface of the metal target is ground to a depth of 0.3 mm using a 400 gauge abrasive paper. In still another embodiment, the milling machine is milled at a milling speed of 4500 rpm and an infeed speed of 900 mm/min, and the surface of the metal target is ground to a depth of 0.5 mm using a No. 400 abrasive paper. In still another embodiment, the milling machine is operated at a milling machine speed of 4500 rpm and a feed rate of 2250 mm/min, and the surface of the metal target is ground to a grinding depth of 0.55 mm using a No. 400 abrasive paper. With the processing conditions of the milling machine and the grinding of the above embodiments, the number of times of washing the target of the metal target can be reduced to one.

It is understood from the above that the grinding depth of the grinding step is positively correlated with the milling machine speed and the milling machine feed rate. Therefore, as the speed of the milling machine or the feed rate decreases, the thickness of the strain layer and the residual stress on the surface of the target can be reduced, thereby reducing the depth of the grinding. However, the reduction of the milling machine speed and the feed rate will also increase the processing time of the target, which will reduce the production efficiency of the target. Therefore, if it is suitable for mass production in the factory, it should be balanced.

According to the results of many experiments, the most suitable processing conditions for the mass production process of the factory are milling machine speed S=1592 rpm, and the feed speed F=318 mm/mm, and grinding with a grinding depth of 0.3 mm using 400-grinding sandpaper.

It can be seen from the above embodiments that an advantage of the method for improving the sputtering rate of the metal target of the present invention is that a suitable grinding step is performed on the strain layer generated on the surface of the metal target after the milling processing. Strain the layer thickness and reduce the stress on the surface of the metal target. Therefore, the sputtering rate of the surface of the metal target can be increased and the batch of the target can be reduced without destroying the texture characteristics of the internal material of the metal target. Moreover, this additional grinding treatment can also improve the smoothness and flatness of the surface of the metal target, and increase the visual perception.

While the present invention has been described above by way of example, it is not intended to be construed as a limitation of the scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100. . . method

102. . . step

104. . . step

200. . . Metal substrate

202. . . surface

204. . . Metal target

206. . . Strain layer

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

1 is a flow chart showing a method of increasing the sputtering rate of a metal target in accordance with an embodiment of the present invention.

Figure 2A is a schematic diagram showing a metal target that has not been processed by a milling machine.

Figure 2B is a schematic view showing the surface of the metal target is not ground after being processed by a milling machine.

Fig. 2C is a schematic view showing the surface of the metal target after grinding by a milling machine and then grinding at a depth of 0.1 mm.

The 2D figure shows a schematic view of the surface of the metal target after grinding by a milling machine and then grinding at a grinding depth of 0.5 mm.

100. . . method

102. . . step

104. . . step

Claims (10)

A method for increasing a sputtering rate of a metal target, comprising: providing a metal target, wherein a surface of the metal target has a strained layer processed by a milling machine, and the milling processing has a milling speed and a Feeding speed; and performing a grinding step on the strained layer to thin the strained layer, wherein one of the grinding steps is positively correlated with both the milling speed and the feed speed. The method of increasing the sputtering rate of a metal target according to claim 1, wherein the grinding step comprises using a sandpaper, and the number of the sandpaper is from 400 to 800. A method for increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 1592 rpm; the feed speed is 318 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.3 mm . The method of increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 398 rpm; the feed speed is 224 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.15 mm . A method for increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 796 rpm; the feed speed is 224 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.2 mm . The method of increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 4500 rpm; the feed speed is 900 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.5 mm . The method of increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 4500 rpm; the feed speed is 2250 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.55 mm . The method of increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 1592 rpm; the feed speed is 318 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.2 mm . The method of increasing the sputtering rate of a metal target according to claim 2, wherein the milling speed is 1592 rpm; the feed speed is 318 mm/min; the number of the abrasive paper is 400; and the grinding depth is 0.4 mm . A method of increasing the sputtering rate of a metal target as claimed in claim 1, wherein the metal target has a purity of from 3N to 6N.