KR20200028371A - DLC coating product including DLC coating layer obtained by coating method for highly adherent graphite - Google Patents

Abstract

The present invention relates to a DLC coating method, and more specifically, to a DLC-coated product including a DLC coating layer which is coated by a high adhesion graphite coating method, wherein adhesion is improved to prevent a coating from being peeled off even under an internal compressive stress of 9-14 GPa or more.

Description

DLC coating product including DLC coating layer obtained by coating method for highly adherent graphite}

The present invention relates to a DLC coating method, and more specifically, to a DLC coating product comprising a DLC coating layer coated with a high adhesion graphite coating method with improved adhesion so that the coating does not peel even under an internal compressive stress of 9-14 GPa or more. .

DLC (Diamond-Like Carbon) has excellent mechanical properties such as high hardness, wear resistance and low friction, and it is especially useful in tribological applications. Is widely used. DLC coating has been mainly researched and developed by PECVD.

The PECVD method uses a hydrocarbon gas such as C ₂ H ₂ or CH _4, and decomposes the hydrocarbon gas strongly with a negative voltage applied to the substrate, so that the gas ions charged with + are negatively charged, and have strong energy and It is known that the process of forming a DLC thin film by pulling it to have an acceleration occurs, and the strong energy spike generated thereby increases the internal density and hardness of the thin film. However, due to the phenomenon that the internal residual stress generated in addition to this, the internal compressive stress of the coating has a property of 2-10 GPa or more, and there is a problem in that peeling occurs when adhesion to the substrate is not good. For example, when forming a DLC using a graphite target on a silicon wafer substrate, a strong compressive stress is present in the coating, and thus, there is a problem that peeling of the coating easily occurs due to poor adhesion to the silicon substrate.

Although various methods for solving this problem are sought, sputtering method is attracting attention because it can reduce internal pollution compared to PECVD method and mass production of batch type method is also gaining attention, but increasing adhesion is easy by simply introducing a buffer layer or cleaning the substrate. It is difficult to solve, and it is very difficult to coat a thin film having a thickness of 1 µm or more, especially in the presence of a strong internal compressive stress.

Therefore, the object of the present invention is a coating method capable of easily performing DLC coating, which is difficult to apply with high internal stress, which is simpler and can be mass-produced, reduces contamination inside the chamber, and is more convenient for sputtering. It is to provide a DLC coating product formed with a coated DLC coating film by a high-adhesion graphite coating method capable of imparting an adhesion force that can withstand high compression stress inside using a method.

The object of the present invention is not limited to the above-mentioned object, and even if not explicitly mentioned, the object of the invention that can be recognized by those skilled in the art from the description of the detailed description of the invention to be described later may also be naturally included. .

In order to achieve the above-mentioned object of the present invention, the present invention includes a DLC coating layer formed by sequentially laminating a buffer layer and a DLC thin film layer on its surface. Even when the internal compressive stress is 11 GPa or more, the adhesive force between the surface and the DLC coating layer is It provides a DLC coating product characterized in that it is maintained.

In a preferred embodiment, the DLC coating layer has a thickness of 1um or more.

In a preferred embodiment, the buffer layer is made of titanium, Cr, Mo or tungsten material.

In a preferred embodiment, the DLC coating layer is a metal target for coating a silicon, ceramic or metal material to be coated with a DLC (Diamond like carbon) thin film in a vacuum chamber, and a metal target that is a titanium, Cr, Mo or tungsten material. Placing a graphite target; A base material cleaning step of cleaning the base material; A target cleaning step of cleaning the target; A buffer layer forming step of depositing the metal target on the base material to form a buffer layer; And a DLC thin film layer forming step of depositing the graphite on the buffer layer to form a DLC thin film layer.

In a preferred embodiment, the base material cleaning step is performed by treating the base material with an RF bias power of less than 400 W in 60 minutes or less and then processing a 400 W or more RF bias power in 10 minutes or less under a pressure of 4 to 8 mTorr.

In a preferred embodiment, the target cleaning step is performed by applying an RF bias power of less than 100 W to the base material under a pressure of 1 to 3 mTorr and processing in less than 15 minutes with a DC power of 80 to 150 W.

In a preferred embodiment, the buffer layer forming step is performed in two steps by applying a DC power of 30 W or less under a pressure of 1 to 3 mTorr and then applying different RF via powers to the base material.

In a preferred embodiment, the second step comprises two steps: applying the RF via power to 200W or more and processing it for 30 minutes or more, and applying the RF via power to 150W or less to process it for 20 minutes or more.

In a preferred embodiment, the DLC thin film layer forming step is performed from step 1 to step 3 under different conditions of DC power and RF bias power under a pressure of 3 to 7 mTorr.

In a preferred embodiment, in the first step, the DC power is applied to 100 W or less, the RF via power is applied to 200 W or more, and processed in less than 10 minutes, and in the second step, the DC power is applied to 400 W or more. The RF via power is not applied and is performed in 120 minutes or less, and the third step is performed by applying the DC power to 500 W or more and the RF bias power to 200 W or less and processing in 240 minutes or less.

According to the present invention described above, as a coating method capable of easily performing DLC coating, which is difficult to apply due to high internal stress, it is possible to more easily and mass-produce, reduce contamination inside the chamber, and more convenient sputtering method for maintenance operation. By using, it is possible to impart an adhesive force to withstand the high compressive stress of the interior to the DLC coating film.

These technical effects of the present invention are not limited to the above-mentioned ranges, and even if not explicitly mentioned, the effects of the invention that can be recognized by those skilled in the art from the description of specific contents for carrying out the invention described below are also Of course it is included.

1A and 1B are FE-SEM observation surfaces and cross-sectional images of a DLC coating layer obtained by graphite coating using a conventionally known sputtering method.
Figure 2 is a photograph of a DLC coating product coated with a high adhesion graphite coating method according to an embodiment of the present invention.
3A and 3B are FE-SEM observation surfaces and cross-sectional images of the DLC coating layer formed on the surface of the DLC coating product shown in FIG. 2.

The terminology used in the present invention was selected from the general terms that are currently widely used while considering the functions in the present invention, but this may vary according to the intention or precedent of a person skilled in the art or the appearance of new technologies. In addition, in certain cases, some terms are arbitrarily selected by the applicant, and in this case, their meanings will be described in detail in the description of the applicable invention. Therefore, the terms used in the present invention should be interpreted based on the general meaning of the terms and the contents described throughout the specification of the present invention, not simply the names of the terms. In particular, when the terms "about", "substantially", etc. of degree are used, it can be interpreted as being used in or close to the value when manufacturing and substance tolerances unique to the stated meaning are given. .

Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, or that one or more other features or It should be understood that the existence or addition possibilities of numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as a second component without departing from the scope of the present invention, and similarly, the second component may also be referred to as a first component.

Hereinafter, the technical configuration of the present invention will be described in detail with reference to the accompanying drawings and preferred embodiments.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. The same reference numerals used to describe the present invention throughout the specification indicate the same components.

The technical feature of the present invention is a coating method capable of easily performing DLC coating, which is difficult to apply due to high internal stress, which is simpler and more mass-producible, reduces contamination inside the chamber, and is more convenient for sputtering. There is a high adhesion graphite coating method capable of imparting an adhesive force to withstand the high compressive stress of the inside to the DLC coating film and a DLC coating product having a DLC coating film coated with the coating method.

In other words, the sputtering method when forming the DLC coating film is attracting attention because it can reduce internal contamination and can also be mass-produced in a batch-type method, but increasing adhesion is difficult to solve simply by introducing a simple buffer layer or cleaning the substrate. This is because it was difficult to coat a thin film having a thickness of 1 µm or more in the presence of a strong internal compressive stress.

Accordingly, the method for coating a high-density graphite of the present invention includes disposing a base material, a metal target, and a graphite target to coat a diamond-like carbon (DLC) thin film in a vacuum chamber; A base material cleaning step of cleaning the base material; A target cleaning step of cleaning the target; A buffer layer forming step of depositing the metal target on the base material to form a buffer layer; And a DLC thin film layer forming step of forming a DLC thin film layer by depositing the graphite on the buffer layer. Here, the base material may be made of silicon, ceramic, or metal as a product for coating.

Particularly, the base material cleaning step is performed by processing the RF bias power of less than 400 W to the base material under 60 to 60 m or less under a pressure of 4 to 8 mTorr, and then processing the RF bias power of 400 W or more to 10 minutes or less. Therefore, the processing of the base material is performed with 60 minutes of strong power at first, and then, at the second stage, a shorter time from higher power is used to prevent damage to the jig or unit of the device that can withstand such high power for a long time. This is because it is thought that cleaning of the cotton substrate is possible. On the other hand, the performance conditions of the base material cleaning step are experimentally determined. If the pressure range is out of the set range, the intensity of the ion impact energy may change or weaken at higher pressures, and plasma generation and maintenance may be difficult at lower pressures. There is a big problem of peeling because it is coated on the substrate with too strong energy, and RF via power was determined because it was applied with sufficient power to remove contamination and oxide of the substrate with an appropriate size. This is because too high a power reaches the limit of RF power and may cause damage to the device. As the base material, a silicon wafer substrate, a ceramic substrate, or a metal substrate is present. Since the adhesion of DLC is affected by the material and surface condition of the substrate, the more difficult the substrate, the more thoroughly the base material should be cleaned. By varying the RF power, a weak RF power is first applied to the bias for a long time of 60 minutes, and then a strong ion shock is applied for a short time of 10 minutes at a higher power of 400W to remove the oxide of the substrate more clearly and the internal components of the substrate This is to make it appear.

The target cleaning step is performed by applying an RF bias power of less than 100 W to the base material under a pressure of 1 to 3 mTorr, and processing it in less than 15 minutes with a DC power of 80 to 150 W. Performing target cleaning removes the oxide generated in the previous process. This is for the reason to remove the contaminants generated after opening the chamber. On the other hand, the conditions for performing the target cleaning step are experimentally determined. If the pressure range is outside the set range, there is a possibility that an oxide layer may be present on the target surface due to the presence of more oxygen and the like as residual gas at higher pressures, and there is also the influence of other gases. If there is too little pressure, it is difficult to generate and maintain plasma, or there is a big problem of peeling due to too strong particle energy, and RF via power does not have any further reason to clean the substrate, but there is no reason to do it. It was decided to maintain the RF bias power to the extent that the particles on the surface were removed from sticking and sticking.

The buffer layer forming step is performed in two stages by applying a DC power of 30 W or less under a pressure of 1 to 3 mTorr, and then applying different RF bias powers to the base material. It may be composed of a first step of processing for 30 minutes or more by applying as and two steps of processing for 20 minutes or more by applying the RF via power to 150 W or less. As described above, the formation of the buffer layer in two steps by varying the RF via power is intended to lower the energy of the tungsten particles colliding with the substrate by reducing the DC power to 20W. However, the first increase of the bias to 200W is to impart a cleaning effect to the substrate, and to induce the formation of a buffer layer in the second stage 100W. Initially, it is attracted by a strong bias to increase the bias to the extent that the buffer layer is hardly formed, so that the substrate is cleaned, thereby increasing the adhesion, and while forming the second stage buffer layer, the bias is lowered to 100W, and the thickness is not very thick at 20W, which is a low DC power. A buffer layer having a strong bond with the substrate was formed. On the other hand, the conditions for performing the buffer layer formation step are experimentally determined. If the pressure range is out of the set range, the residual metal may not be included in the formation of the buffer layer with a pure metal layer, and plasma may be generated when sputtering with too low power. It is difficult to maintain, and the RF bias power was determined as the reason for approaching the proper RF bias power through several experiments when sputtering at a low DC power. In addition, various metal materials may be used as the material of the buffer layer. Titanium or tungsten materials may be advantageous for titanium or tungsten materials because of their high affinity with silicon wafers and DLC coatings and excellent adhesion. On the other hand, metals such as Cr and Mo can also be used because they are judged to have high affinity with silicon or with DLC.

 The DLC thin film layer forming step may be performed from step 1 to step 3 under different conditions of DC power and RF bias power under a pressure of 3 to 7 mTorr. As an embodiment, in step 1, DC power is applied to 100 W or less and RF bias power is applied. Is applied over 200W and processed in less than 10 minutes. In step 2, DC power is applied to 400W or more, RF via power is not applied, and processed in 120 minutes or less, and in step 3, DC power is 500W or more. It is applied and RF via power is applied to 200W or less and can be performed by processing in 240 minutes or less. Forming the DLC thin film layer in three steps by varying the DC power and RF bias power as described above reduces damage to the buffer layer and gradually increases the power so that peeling does not occur due to ion bombardment and increasing the DC power in the second step has a somewhat higher power. Is because DLC formation is possible, and the reason that the bias is not applied is because it is confirmed that the damage and peeling of the coating layer with high DC power can be mitigated by setting the RF bias to no bias, that is, 0 W. In particular, applying DC power to 100 W or less in step 1 can damage the buffer layer or induce peeling when applying too high DC power in a state where the buffer layer is laid and the underlying thin film is deposited. This is because it is preferable to use it, and the RF bias power is increased to 200 W to make the tungsten and the DLC layer bond to each other with strong energy to induce a bonding layer with the tungsten layer as a buffer layer. In addition, the application of DC power higher than 400W in step 2 is a strong energy and the DLC layer is formed on the lower buffer layer so that it is closely coupled with the DLC layer formed in step 1, but the reason why the RF substrate bias is not biased is not peeled off. This is because the RF bias power 0, that is, the bias power is not applied, is because when the RF substrate bias is applied too high, there is a high possibility of peeling of the thin film and stress may be increased. In addition, the application of DC power to 500W or higher in step 3 is due to the reason for applying an impact (ion shock) to the coating layer with an RF substrate bias under strong DC power to increase the hardness to a strong upper layer. RF via power is no bias. In the case of applying the bias below 200W, it may give very little bias, especially below 10W. The reason for applying the RF bias to 200W by increasing the bias is to some degree with stronger energy while the adhesion is secured through 2 steps. This is for the reason for bonding to the finished coating layer and increasing the hardness of the DLC coating layer. The sputtering time was also designed according to the characteristics for each step, so that the DLC coating layer of the initial lower layer was well combined with the buffer layer. At this time, the coating may be softened in steps 1 and 2 when coated for too long, and coated with strong energy in step 3 and bias 200W. It is for this reason that it is different for each step because it can increase the time to deposit a layer with a high hardness to a certain degree.

On the other hand, the conditions for performing the DLC thin film layer formation are experimentally determined, and when the pressure range is out of the set range, there is a problem in the hardness and adhesion of the coating, and even RF via power does not cause peeling of the coating and secures the hardness of the DLC coating. It was decided for the reason I thought as a possible condition.

The DLC coating product of the present invention includes a DLC coating layer formed by sequentially laminating a buffer layer and a DLC thin film layer on its surface, and has a characteristic that the adhesion between the surface and the DLC coating layer is maintained even when the internal compressive stress is 11 GPa or more, 1um It has an ideal thickness. In order to maintain the adhesion characteristics and thickness, the DLC coating method and the material of the buffer layer are important. As an embodiment, the buffer layer may be made of titanium or tungsten material. Here, the DLC thin film layer may be a high hardness film that does not contain hydrogen, such as aC, nC, iC, ta-C, sp ² , sp ³ , hydrogen free.

Example 1

A substrate and a tungsten target and a graphite target, which are base materials for coating a DLC (Diamond like carbon) thin film in a vacuum chamber, are arranged, and according to the sputtering conditions of Tables 1 to 4, substrate cleaning, target cleaning, buffer layer coating, and DLC thin film coating Each was performed to form a DLC coating layer 1 (HSC-46).

Substrate cleaning conditions division RF substrate buyer power (W) Time (min) Pressure (mTorr) Ar (SCCM) Stage 1 300 60 5 130 Stage 2 400 10 5 130

Target cleaning condition RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) 100 100 10 2 50

Buffer layer coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stage 1 200 20 30 2 50 Stage 2 100 20 20 2 50

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 14.570 Stage 2 0 400 120 5 130 Stage 3 200 500 240 5 130

Example 2

DLC coating layer 2 (HSC-24) was formed by performing the same method as in Example 1, except that DLC thin film coating was performed under the sputtering conditions shown in Table 5.

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 2.702 Stage 2 0 400 60 5 130 Stage 3 10 500 60 5 130

Example 3

DLC coating layer 3 (HSC-25) was formed by performing the same method as in Example 1, except that DLC thin film coating was performed under the sputtering conditions shown in Table 6.

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 5.072 Stage 2 0 400 120 5 130 Stage 3 10 500 120 5 130

Example 4

DLC coating layer 4 (HSC-39) was formed by performing the same method as in Example 1, except that DLC thin film coating was performed under the sputtering conditions shown in Table 7.

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 5.056 Stage 2 0 400 120 5 130 Stage 3 10 500 240 5 130

Example 5

DLC coating layer 5 (HSC-40) was formed in the same manner as in Example 1, except that DLC thin film coating was performed under the sputtering conditions shown in Table 8.

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 11.658 Stage 2 0 400 120 5 130 Stage 3 20 500 240 5 130

Example 6

DLC coating layer 6 (HSC-41) was formed by performing the same method as in Example 1, except that DLC thin film coating was performed under the sputtering conditions shown in Table 9.

DCL thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stress (GPa) Stage 1 200 100 10 5 130 13.310 Stage 2 0 400 120 5 130 Stage 3 30 500 240 5 130

Comparative example

A comparative example coating film (HSC-23) was obtained by performing the same method as in Example 1, except that sputtering was performed under the substrate cleaning conditions and the DLC thin film coating conditions as shown in Table 10 below.

Substrate cleaning conditions RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) 300 120 5 130 DLC thin film coating conditions division RF substrate buyer power (W) DC power (W) time
(min) pressure
(mTorr) Ar
(SCCM) Stage 1 200 10 30 5 130 Stage 2 100 20 30 5 130 Stage 3 50 50 30 5 130 Stage 4 20 100 30 5 130 Stage 5 15 200 30 5 130 Step 6 10 300 30 5 130

Experimental Example 1

DLC coating layer 1 (HSC-46), DLC coating layer 3 (HSC-25) to DLC coating layer 6 (HSC-41) obtained in Examples 1 and 3 to 6, respectively, coated with the high adhesion graphite coating method of the present invention Figures 2a to 2f show the pictures immediately after deposition of the formed DLC coating products and the pictures immediately after deposition of the comparative example coating products obtained in Comparative Examples.

As shown in FIGS. 2A to 2E, the DLC product formed with the DLC coating layer formed by the high adhesion graphite coating method of the present invention has relatively good adhesion and does not peel, but is coated with comparative example conditions as shown in FIG. 2F. In the comparative example product, it can be seen that the DLC coating layer was peeled off.

Experimental Example 2

DLC coating layer 1 (HSC-46), DLC coating layer 4 (HSC-39) to DLC coating layer 6 (HSC-41) obtained in Examples 1 and 3 to 6, respectively, coated with the high adhesion graphite coating method of the present invention The FE-SEM observation pictures are shown in FIGS. 3A to 3E.

It can be seen from FIG. 3A that the surface image of the DLC coating layer 1 (HSC-46) is shown, since the surface shows a clean and smooth state, the adhesion between the DLC coating layer and the substrate is considerably good. 3B to 3E showing cross-sectional images of DLC coating layer 1 (HSC-46), DLC coating layer 4 (HSC-39) to DLC coating layer 6 (HSC-41), respectively, while the boundary between the buffer layer and the DLC thin film is unclear. It can be seen that not only shows a smooth connection, but also shows that the thickness of the DLC coating layer is 1 μm or more.

Particularly, when compared with FIGS. 1A and 1B showing the FE-SEM observation surface and cross-sectional images of the DLC coating layer obtained by graphite coating by a conventionally known sputtering method, the superiority of the DLC coating layer obtained by the high adhesion graphite coating method of the present invention can be clearly seen. have.

Particularly, Example 1 shows that adhesion is maintained even when deposited under a stress of 14 GPa or more, so it can be seen that the high adhesion graphite coating method of the present invention has an effect of improving adhesion.

The present invention has been shown and described with reference to preferred embodiments, as described above, but is not limited to the above-described embodiments and to those skilled in the art to which the present invention pertains without departing from the spirit of the present invention. Various changes and modifications will be possible.

Claims (10)

A DLC coating product comprising a DLC coating layer formed by laminating a buffer layer and a DLC thin film layer sequentially on its surface, wherein the adhesion between the surface and the DLC coating layer is maintained even when the internal compressive stress is 11 GPa or more.
According to claim 1,
DLC coating product, characterized in that the DLC coating layer has a thickness of 1um or more.
According to claim 1,
The buffer layer is made of titanium, Cr, Mo or tungsten material, DLC coating product.
According to any one of claims 1 to 3, wherein the DLC coating layer
Disposing a metal target and a graphite, titanium, Cr, Mo or tungsten material target and graphite target for a coating material made of silicon, ceramic or metal to coat a DLC (Diamond like carbon) thin film in a vacuum chamber; A base material cleaning step of cleaning the base material; A target cleaning step of cleaning the target; A buffer layer forming step of depositing the metal target on the base material to form a buffer layer; And a DLC thin film layer forming step of depositing the graphite on the buffer layer to form a DLC thin film layer.
The method of claim 4,
The base material cleaning step is a DLC coating product characterized in that the base material is processed under a pressure of 4 to 8 mTorr to treat the RF bias power of less than 400 W in 60 minutes or less, and then process the RF bias power of 400 W or more in 10 minutes or less.
The method of claim 4,
The target cleaning step is a DLC coating product characterized in that it is performed by applying less than 100 W of RF bias power to the base material under a pressure of 1 to 3 mTorr and processing with DC power of 80 to 150 W for less than 15 minutes.
The method of claim 4,
The buffer layer forming step is a DLC coating product characterized in that it is performed in two steps by applying different RF via power to the base material after applying a DC power of 30 W or less under a pressure of 1 to 3 mTorr.
The method of claim 4,
The second step is a DLC coating product, characterized in that it consists of two steps of applying the RF buyer power to 200W or more and processing it for 30 minutes or more, and two steps of applying the RF buyer power to 150W or less and processing for 20 minutes or more.
The method of claim 4,
The DLC thin film layer forming step is a DLC coating product characterized in that the DC power and RF via power are performed under the conditions of 3 to 7 mTorr from 1 to 3 steps under different conditions.
The method of claim 9,
In the first step, the DC power is applied to 100W or less, and the RF via power is applied to 200W or more and is performed in less than 10 minutes,
In the second step, the DC power is applied to 400W or more, and the RF via power is not applied and is processed in 120 minutes or less,
The third step is a DLC coating product characterized in that the DC power is applied to 500W or more and the RF via power is applied to 200W or less and processed in 240 minutes or less.

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