KR101240912B1 - Gas valve assembly of atomic layer deposition apparatus comprising lip seal - Google Patents

Abstract

The present invention relates to a gas valve assembly of an atomic layer deposition apparatus, comprising: a drive shaft having a plurality of internal flow paths, the inlet of which is formed on an outer circumferential surface thereof; A housing surrounding the outer circumference of the drive shaft and having a plurality of gas supply holes corresponding to the plurality of internal passages; A plate-shaped body portion fixed to an inner wall of the housing and having an open portion through which the drive shaft penetrates, and a funnel-shaped seal portion formed by bending the opening portion side peripheral portion, and installed between the drive shaft and the housing, the inside of each of which is installed; The present invention provides a gas valve assembly including a lip seal that forms a plurality of annular flow passages in one-to-one communication with a flow passage and gas supply holes corresponding to each internal flow passage.

According to the present invention, even if the atomic layer deposition apparatus is applied to a high temperature process, it is possible to prevent the risk of leakage in the gas valve assembly or contamination of the inside of the chamber due to magnetic fluid.

Atomic layer deposition, gas valve assembly, lip seal

Description

Gas valve assembly of atomic layer deposition apparatus comprising lip seal

1 is a state of use of the gas valve assembly in a semi-batch atomic layer deposition apparatus

2 is a cross-sectional view of the gas valve assembly coupled to the top of the process chamber;

3 is a partially enlarged view of a portion A of FIG.

4 is a cross-sectional view of a gas valve assembly according to an embodiment of the present invention.

5A and 5B are perspective and side views of the lip seal

6 is a view showing another embodiment of a fixing member

7 is a cross-sectional view showing a state in which a backflow preventing purge gas supply hole is formed in a housing;

Description of the Related Art [0002]

100: gas valve assembly 110: drive shaft

120 housing 122 flange

130,140,150,160: First, second, third and fourth gas supply holes

171,172,173,174: 1st, 2nd, 3rd and 4th Euro

180: lip seal 181: body

182: opening 183: seal

190: fixing member 191: lower fixing member

192: spring 193: seal auxiliary support member

194: upper fixing member 200: back flow prevention purge gas supply hole

The present invention relates to a gas valve assembly of an atomic layer deposition apparatus, and more particularly, to a gas valve assembly including a lip seal.

Generally, a semiconductor device is manufactured through a process of forming a circuit pattern on a silicon wafer and a packaging process of cutting the wafer into a predetermined size and encapsulating the wafer with an epoxy resin.

In order to form a circuit pattern on a wafer, a thin film deposition process of forming a predetermined thin film, a photolithography process of forming a photoresist pattern by applying photoresist to the deposited thin film and exposing and developing the photoresist pattern, An etching process of patterning a thin film, an ion implantation process of injecting specific ions into a predetermined region of the wafer, and a cleaning process of removing impurities must be performed.These processes are performed in a process chamber in which an optimal environment is formed for the process. Proceed.

Among these, the thin film deposition process can be largely divided into PVD (Physical Vapor Deposition) method using physical collision, such as sputtering method, and CVD (Chemical Vapor Deposition) method using chemical reaction. And it is generally used because of the excellent step coverage (step coverage). The CVD method is divided into APCVD (Atmospheric pressure CVD), LPCVD (Low pressure CVD), PECVD (Plasma Enhanced CVD) method.

Recently, ALD (Atomic Layer Deposition: ALD) method, which has much higher film uniformity or step coverage than the conventional method, requires a gate-oxide layer and a capacitor dielectric layer requiring a fine pattern. ), And is widely used for deposition processes such as diffusion barrier layers.

According to the ALD method, since the reactants react only on the surface of the substrate, the thickness of the film deposited in one raw material supply cycle is constant, and thus, the thickness of the thin film can be precisely controlled by controlling the number of raw material feed cycles.

The deposition process of an atomic layer thin film consisting of A + B compounds of A and B materials is described as follows.

First, the wafer is placed in the process chamber and vacuum pumped to form a process atmosphere. Then, A material is introduced into the process chamber and adsorbed onto the wafer surface. Subsequently, purge gases such as Ar and N ₂ are introduced to purge the residual gas.

When the new B material is introduced into the chamber after the purge process is completed, the B material reacts with the A material already deposited on the wafer to form a thin film of Compound A + B. Subsequently, once the purge gas is introduced again to remove residual gas, one deposition cycle is completed. By repeating this process as necessary, a thin film having a desired thickness can be obtained.

Since the atomic layer deposition method has a very thin thickness obtained through one cycle process, in order to obtain the required thin film thickness, the above-described deposition process of the above-mentioned cycle must be repeated several times to several hundred times.

Therefore, in order to increase productivity, a semi batch process chamber which processes 4-5 sheets at a time is commonly used.

In addition, since the atomic layer deposition apparatus uses a plurality of process gases and purge gases, if a separate gas inlet pipe and a valve are installed for each gas, the equipment is complicated and the on / off operation of the valve per process must be repeated hundreds of times. Therefore, not only the life of the valve is shortened, but there is a problem that it is difficult to match the operation order and time of the electric signal device, pneumatic actuator, and valve on / off device for driving the valve.

Proposed to solve this problem is a gas valve assembly having a simpler configuration, and can effectively control the gas injection sequence.

FIG. 1 illustrates a semi-batch atomic layer deposition apparatus in which such a gas valve assembly 10 is used, and only a gas valve assembly 10 and a wafer w underneath thereof are shown for convenience of description.

The gas valve assembly 10 includes a cylindrical housing 12 and a drive shaft 11 penetrating up and down the inside of the housing 12, and a plurality of internal flow paths are formed in the drive shaft 11.

First, second, third, and fourth gas supply pipes 21, 22, 23, and 24 each connected to the inner passage are connected to a side surface of the housing 12, and a lower end of the drive shaft 11 communicates with the inner passage. The first, second, third and fourth injectors 31, 32, 33 and 34 are connected.

The first, second, third, and fourth injectors 31, 32, 33, and 34 are formed with a plurality of injection holes (not shown) at the bottom and rotate in a pinwheel shape by the drive shaft 11, so It serves to spray the first raw material, purge gas, the second raw material, the purge gas sequentially on the top. In this case, Ar or N ₂ is used as the purge gas.

FIG. 2 is a cross-sectional view of the gas valve assembly 10 fastened to the upper portion of the process chamber 40. First, second, third and fourth gas supply pipes 21, 22, 23, and 24 are provided at an outer circumference of the housing 12. The first, second, third, and fourth gas supply holes 13, 14, 15, and 16, to which the) is connected, are formed, and the flange 12a is coupled to the process chamber 40 at a lower portion thereof. In addition, an O-ring 42 is installed to vacuum seal the process chamber 40 having a vacuum inside.

Inside the drive shaft 11, the first, second, third and fourth gas supply holes 13, 14, 15 and 16 and the corresponding first, second, third and fourth internal flow paths 17, 18, 19 and 20, respectively. Is formed, the inlet of the first, second, third, fourth internal passage (17, 18, 19, 20) is formed on the side of the drive shaft 11, the outlet is formed on the lower end of the drive shaft (11).

As shown in FIG. 1, first, second, third, and fourth injectors 31, 32, 33, and 34 are connected to each outlet of the inner channel in a pinwheel shape.

Thus, for example, the first raw material supplied through the first gas supply pipe 21 is injected through the first gas supply hole 13, the first internal passage 17, and the first injector 31, The purge gas supplied through the second gas supply pipe 22 is injected through the second gas supply hole 14, the second internal flow path 18, and the second injector 32, and opens the third gas supply pipe 23. The second raw material supplied through the third gas supply hole 15, the third internal passage 19 and the third injector 33 is injected, the purge gas supplied through the fourth gas supply pipe 22 is It is injected through the fourth gas supply hole 16, the fourth internal passage 20, and the fourth injector 34.

As the driving shaft 11 rotates as described above, each of the injectors 31, 32, 33, and 34 sequentially passes through the upper portions of the plurality of wafers arranged in the circumferential direction, and thus the first raw material, the purge gas, and the second raw material. As the purge gas is sequentially sprayed, the atomic layer deposition process for a plurality of wafers is performed at once.

Meanwhile, raw materials and purge gas introduced through the first, second, third, and fourth gas supply holes 13, 14, 15, and 16 in FIG. 2 should not be mixed with each other, so that each passage is formed inside the housing 10. There is a need for sealing means for isolating each other. In the related art, magnetic seals 30 are mainly used as shown in FIG.

Magnetic seal refers to the formation of a liquid O-ring using the characteristics of a magnetic fluid that maintains a certain form by magnetic force. Magnetic fluid is a fluid that stabilizes and disperses magnetic powders such as Fe3O4 in a base oil in a colloidal shape, and then adds a surfactant to prevent precipitation or agglomeration. Since it can be controlled reversibly, it is widely used as a working fluid for shaft seals and vacuum seals.

Since the magnetic powder in the magnetic fluid is generally ultrafine powder of 0.01 to 0.02 micrometers, it performs brown movement peculiar to the ultrafine particles, so that the concentration of magnetic powder in the magnetic fluid is kept constant even when external magnetic fields, gravity and centrifugal force are applied. Therefore, the sealing performance is excellent, there is an effect that can prevent the generation of particles due to the friction of the drive member.

FIG. 3 is an enlarged view of portion A of FIG. 2 and schematically illustrates a configuration of the magnetic seal 30 formed between the drive shaft 11 and the housing 12. According to this, a plurality of permanent magnets 31 and pole pieces 32 having a plurality of pointed portions at end portions are alternately installed on the inner wall of the housing 12, and the magnetic portions are formed at the pointed portions of the pole pieces 32. Inject fluid 33.

The injected magnetic fluid 33 agglomerates to the peaks of the pole pieces 32 due to the magnetic field applied from the permanent magnet 31 and the inherent viscosity of the magnetic fluid 33, and the driving shaft 11 and the pole pieces 32. The annular magnetic seal 30 is formed along the outer circumferential surface of the drive shaft 11 while filling the gap between the peaks.

However, although the magnetic seal has a wide range of applications as a sealing means of the rotating body, it has some problems as follows.

First, it is vulnerable to temperature due to the use of magnetic fluid, and is not suitable for high temperature processes requiring a hot wall because the magnetic fluid may be lost or the magnetic fluid may be vaporized above 100 ° C. This is because the magnetic fluid is leaked when the magnetic fluid is lost, and the magnetic seal is leaked. When the magnetic fluid is vaporized, the vaporized material flows into the chamber and acts as a pollution source.

Second, since the raw material is in contact with the magnetic seal during the flow, there is a risk that the magnetic fluid and the raw material react with each other to generate pollutants, and even if the magnetic fluid does not react, it acts as a source of contamination if the magnetic fluid enters the chamber together with the raw material. There is a risk of causing secondary problems in the process or equipment.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a method of preventing a leak occurring in a gas valve assembly of an atomic layer deposition apparatus or contamination inside a chamber due to magnetic fluid.

The present invention to achieve the above object, the drive shaft having a plurality of internal passages, the inlet of the inner passage is formed on the outer peripheral surface; A housing surrounding the outer circumference of the drive shaft and having a plurality of gas supply holes corresponding to the plurality of internal passages; A plate-shaped body portion fixed to an inner wall of the housing and having an open portion through which the drive shaft penetrates, and a funnel-shaped seal portion formed by bending the opening portion side peripheral portion, and installed between the drive shaft and the housing, the inside of each of which is installed; The present invention provides a gas valve assembly including a lip seal that forms a plurality of annular flow passages in one-to-one communication with a flow passage and gas supply holes corresponding to each internal flow passage.

The lip seal is preferably made of a fluorine resin series or carbon graphite material.

The lip seal is preferably installed at least one upper and lower sides of the respective inlet passage.

It is preferable that a fixing member for fixing the body portion is installed on the inner wall of the housing.

The fixing member includes a lower fixing member fixed to the inner wall of the housing; A seal auxiliary support member for supporting an elastic force of the lip seal; And an upper fixing member for fixing the lip seal together with the lower fixing member, and an elastic member is installed between the lower fixing member and the seal supporting member.

Preferably, the elastic member is provided in a recess or step portion in the lower fixing member, and a seal auxiliary support member having a curved surface is inserted between the recess or step portion and the lip seal.

The gas supply hole includes a first raw material supply hole, a second raw material supply hole, and one or more purge gas supply holes.

The housing may further include a backflow preventing purge gas supply hole communicating with the inside of the chamber to which the housing is coupled.

Hereinafter, with reference to the drawings will be described a preferred embodiment of the present invention.

4 is a cross-sectional view of the gas valve assembly 100 according to the embodiment of the present invention, the drive shaft 110 is coupled to the cylindrical housing 120 through the up and down, the first side, the second side of the housing 120 The 3,4 gas supply holes 130, 140, 150, and 160 are spaced apart from each other by a predetermined distance, and the lower part of the housing 120 has a flange 112 for fastening to the upper portion of the process chamber.

In addition, as in the prior art, the first, second, third, and fourth gas supply holes 130, 140, 150, and 160 of the housing 120 and the corresponding first, second, third, and fourth internal passages 171, 172, 173, 174 are formed in the drive shaft 110. .

Inlets of the first, second, third, and fourth internal passages 171, 172, 173, and 174 are formed at the same height as the first, second, third, and fourth gas supply holes 130, 140, 150, and 160 at the sides of the driving shaft 110, and the outlet is the driving shaft 110. It is formed at the lower end of the).

The first, second, third and fourth gas supply holes 130, 140, 150, and 160 of the housing 120 are connected to the first raw material supply pipe, the purge gas supply pipe, the second raw material supply pipe, and the purge gas supply pipe, respectively. The first raw material, the purge gas, the second raw material and the purge gas are respectively supplied to the internal flow paths 171, 172, 173 and 174. In this case, Ar or N ₂ is used as the purge gas.

Since the lower end of the drive shaft 110 is located inside the chamber and the injector is coupled to the outlet of each of the internal flow paths 171, 172, 173, 174, when the drive shaft 110 is rotated, the injector rotates and the first raw material, purge gas, A second raw material and a purge gas are sequentially sprayed to deposit an atomic layer thin film.

The gas valve assembly 100 of the present invention is installed between the drive shaft 110 and the housing 120 to communicate only the internal passages 171, 172, 173, 174 and the gas supply holes 130, 140, 150, and 160 corresponding to each other, and the other internal passages and the gas supply holes. It is characterized in that the lip seal 180 is used as the sealing means to isolate.

The lip seal 180 has a disc shaped body portion 181 having an opening 182 in the center and a peripheral edge around the opening 182, as shown in the perspective and side views shown in FIGS. 5A and 5B. The addition is made of a seal portion 183 formed in a funnel shape bent in one direction.

The opening 182 is a portion through which the drive shaft 110 passes, and the body 181 is fixed to the inner wall of the housing 120. In order to fix the body 181, the fixing member 190 must be installed on the inner wall of the housing 120.

At this time, the seal portion 183 protrudes to the outside of the fixing member 190 and the periphery thereof is adjacent to the drive shaft 110. The gap between the periphery of the seal portion 183 and the drive shaft 110 should be maintained at several micrometers or less. The gas may be prevented from flowing up and down the lip seal 180.

For example, in FIG. 4, if one lip seal 180 is installed one by one above and below the entrance of the first inner flow passage 171 formed on the outer circumference of the driving shaft 110, the driving shaft 110 and the housing 120 are disposed between the driving shaft 110 and the housing 120. The lip seal 180 forms an annular flow path that is isolated from other internal flow paths and gas supply holes.

Since the annular flow path formed along the outer circumference of the drive shaft 110 communicates with the first internal flow path 171 and the first gas supply hole 130, the raw material supplied through the first gas supply hole 130 is It diffuses along the annular flow path and flows into the chamber through the first internal flow path 171.

Thus, by installing the lip seal 180 above and below the inlet of the first, second, third, and fourth internal passages 171, 172, 173, 174, each of the internal passages and the gas supply holes may be isolated from the other internal passages and the gas supply holes. In this case, two or more lip seals 180 may be installed in one place to increase seal performance.

On the other hand, the lip seal 180 is not only exposed to the raw material and purge gas, but also affected by the high heat transmitted from the process chamber should be manufactured using a material having excellent heat resistance and oxidation resistance. In the present invention, a fluororesin-based or carbon graphite material including polytetrafluoroethylene (PTFE) or Tedra fluorethylene-perfluoro alkyl vinyl ether copolymer (PFA), or the like, commonly referred to as teflon, is used.

On the other hand, the fixing member 190 for fixing the lip seal 180 may be a shape having an insertion groove that is simply inserted into the body portion 181, Figure 6 proposes a different type of fixing member 190.

That is, the lower fixing member 191 attached to the inner wall of the housing 120 fixes the body portion 181 of the lip seal 180 at the bottom, and the upper fixing member 194 is the body of the lip seal 180. Fix the part from the top.

The seal portion 183 of the lip seal 180 is bent downwardly and maintains a gap with the outer circumference of the drive shaft 110 in its own elasticity, but as shown in FIG. 6 to maintain the gap more stably. Support member 193 may be provided.

The seal auxiliary support member 193 has a ring shape having a circular cross section, and supports the seal portion 183 of the lip seal 180 from the bottom while being subjected to elastic force by the spring 192 installed on the lower fixing member 191. It is preferable to install a plurality of springs 192 at equal intervals about the drive shaft 110 so that the seal auxiliary support member 193 can support the seal portion 183 of the lip seal with a uniform elastic force.

Meanwhile, in order to support the spring 192 and the seal auxiliary support member 193, a predetermined recess or step may be formed in the lower fixing member 191.

In the above description, a case in which purge gas is supplied through two paths, that is, through the second and fourth gas supply holes 140 and 160 and the second and fourth internal flow paths 172 and 174, is provided. It is also possible.

In this case, the drive shaft 110 has three internal flow paths, and also has three gas supply holes corresponding to the internal flow paths. Since purge gas must be supplied between supply cycles of the first and second raw materials, the purge gas If there is only one internal flow path, the purge gas injector connected to the outlet should be branched into two paths.

FIG. 7 is a cross-sectional view of the gas valve assembly 100 in which a backflow preventing purge gas supply hole 200 is further formed at the bottom of the housing 120. This is to continuously inject a purge gas such as Ar, N _{2 in} order to prevent a thin film deposited or particles generated by the back flow of the raw material or other process residual gas into the gas valve assembly 100.

According to the present invention, even if the atomic layer deposition apparatus is applied to a high temperature process, it is possible to prevent the risk of leakage in the gas valve assembly or contamination of the inside of the chamber due to magnetic fluid.

Claims (9)

A drive shaft having a plurality of internal flow paths, the inlet of which is formed on an outer circumferential surface thereof; A housing surrounding the outer circumference of the drive shaft and having a plurality of gas supply holes respectively corresponding to the plurality of internal passages; A plate-shaped body portion fixed to an inner wall of the housing and having an opening portion through which the drive shaft penetrates, and a funnel-shaped seal portion formed by bending a side portion of the opening portion, and is installed between the drive shaft and the housing, A lip seal forming a plurality of annular flow passages in one-to-one communication with an inner flow passage and a gas supply hole corresponding to each inner flow passage; Fixing member installed on the inner wall of the housing for fixing the body portion Gas valve assembly comprising a The method of claim 1, The lip seal is a gas valve assembly made of fluorine resin series or carbon graphite material The method of claim 1, At least one lip seal is installed between each of the inner flow path inlets; delete The method of claim 1, Wherein: A lower fixing member fixed to the inner wall of the housing; A seal auxiliary support member for supporting an elastic force of the lip seal; An upper fixing member for fixing the lip seal together with the lower fixing member Gas valve assembly comprising a The method of claim 5, A gas valve assembly having an elastic member installed between the lower fixing member and the seal supporting member. The method of claim 6, The elastic member is installed in the recess or step portion in the lower fixing member, the gas valve assembly is inserted between the recess or step portion and the lip seal seal supporting member having a curved surface The method of claim 1, The gas supply hole includes a gas valve assembly including a first source material supply hole, a second source material supply hole, and one or more purge gas supply holes. The method of claim 1, The housing has a gas valve assembly further formed with a back flow prevention purge gas supply hole in communication with the interior of the chamber to which the housing is coupled

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