JP2010186788A - Atomic layer deposition apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress occurrence of deposits deposited inside an apparatus, relating to an atomic layer deposition apparatus for forming an alumina film which is based on the premise of low temperature treatment around 300°C. <P>SOLUTION: A high frequency generation source 108 is provided at the upper part of a deposition chamber 102, and a high frequency power supplying part 109 for supplying high frequency current is connected to the high frequency generation source 108. A material gas supply part 151 for supplying material gas of aluminum to the deposition chamber 102 is connected to a gas introducing opening 105. An oxidizing gas supply part 161 for supplying oxygen gas to the deposition chamber 102 is connected to a gas introducing opening 106. A deposition preventing film 111 is formed on the inner wall of the deposition chamber 102 comprising organic resin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an atomic layer growth apparatus and method for forming a thin film by supplying a source gas onto a substrate in a gas phase.

  In recent years, an atomic layer deposition (ALD) method has attracted attention as a technique having various characteristics such that a high-quality thin film can be formed in a more homogeneous state at a low temperature of about 300 ° C. The atomic layer growth method is a technique for forming a thin film in units of atomic layers by alternately supplying raw materials of respective elements constituting a film to be formed to a substrate. In the atomic layer growth method, only one layer or n layer (n is an integer of 2 or more) is adsorbed on the surface while the raw materials for each element are supplied, and excess raw materials are prevented from contributing to growth. According to the atomic layer growth method, it has high shape adaptability and film thickness controllability as in general CVD, and as a technology that can form a uniform thin film with a high reproducibility over a wider area at a lower temperature, Application to the production of large-screen flat panel displays is under consideration.

  As an atomic layer growth apparatus corresponding to an increase in size, since a rectangular substrate having a side of several tens of centimeters is targeted, a horizontal apparatus that supplies gas in parallel to the substrate is generally used. As is well known, in a horizontal apparatus, gas is supplied in parallel to the substrate, the structure of the apparatus is simple, and the structure is easy to apply to an increase in the size of the substrate. In addition, as described above, the atomic layer growth method has a self-stopping action of growth, and compared with other chemical vapor deposition methods, the state of the formed film has less influence on the distribution of the supplied gas. Not be. For this reason, even when the distance from the gas supply port is greatly different with the increase in size of the substrate, a uniform film can be expected to be formed over the entire area of the substrate.

JP-A-2005-340281

  By the way, in the growth apparatus as described above, since the supplied raw material (gas) comes into contact with the inner wall of the apparatus, deposits adhere to the inner wall. When this deposit increases, particles due to the peeling of the deposit are likely to be generated, and this adheres to the product and becomes a foreign substance, thereby reducing the yield (yield) of the product. For this reason, cleaning inside the apparatus is important. For cleaning the inside of the apparatus, for example, dry cleaning using chlorine gas is used (see Patent Document 1). In this technique, deposits are removed by alumina using chlorine gas. However, such dry cleaning requires high-temperature processing. For example, when chlorine gas is used, it has been confirmed that deposits made of alumina cannot be removed unless the temperature exceeds 500 ° C.

  However, in the atomic layer growth apparatus intended for flat panel display manufacturing as described above, the temperature of film formation is at most about 300 ° C., and it does not have a structure that can withstand high temperatures exceeding 500 ° C. For example, a high-temperature treatment exceeding 500 ° C. cannot be performed because a polymer material that can withstand about 300 ° C. is used for the seal portion for obtaining the hermeticity of the apparatus. Thus, in an atomic layer growth apparatus for forming an alumina film, it is difficult to apply the dry cleaning as described above, and it is not easy to suppress the generation of deposits deposited inside the apparatus.

  The present invention has been made to solve the above-described problems. In an atomic layer growth apparatus for forming an alumina film that is premised on a low-temperature treatment of about 300 ° C., deposition deposited inside the apparatus. The object is to make it possible to easily suppress the generation of objects.

  An atomic layer growth apparatus according to the present invention includes a deposition chamber in which a substrate to be deposited is disposed, a source gas supply means for supplying an aluminum source gas to the deposition chamber, and a substrate gas by supplying the source gas. An oxidizing gas supply means for supplying an oxidizing gas for oxidizing the adsorbing layer formed in the film forming chamber, an exhaust means for exhausting the inside of the film forming chamber, and an organic resin on the inner wall of the film forming chamber. A deposition prevention film formed at least, and the deposition prevention film is oxidized and vaporized by an oxidizing gas. The organic resin may be a polyparaxylylene resin.

  In the atomic layer growth apparatus, the oxidizing gas supply means may be at least one of a plasma generating means for generating oxygen plasma as the oxidizing gas and an ozone generating means for generating ozone as the oxidizing gas.

  The atomic layer growth method according to the present invention includes a first step of forming a deposition prevention film made of an organic resin on an inner wall of a film formation chamber in which a substrate to be deposited is disposed, and a substrate to be deposited. A second step of supplying an aluminum source gas to the film forming chamber and forming an adsorption layer made of the component of the source gas on the substrate; and after exhausting the source gas from the film forming chamber, an oxidizing gas is supplied. And a third step of forming an aluminum oxide layer on the substrate by oxidizing the adsorption layer, and the deposition preventing film is made of an organic resin that is oxidized and vaporized by an oxidizing gas. The organic resin may be a polyparaxylylene resin.

  In the atomic layer growth method, the oxidizing gas may be at least one of oxygen plasma and ozone.

  As described above, according to the present invention, the deposition preventing film made of the organic resin that is oxidized and vaporized by the oxidizing gas is formed on the inner wall of the film forming chamber. In the atomic layer growth apparatus for forming the alumina film thus formed, an excellent effect is obtained that generation of deposits deposited inside the apparatus can be suppressed.

It is a block diagram which shows the structure of the atomic layer growth apparatus in embodiment of this invention. It is explanatory drawing for demonstrating the state of the surface of the deposition prevention film | membrane 111 in the process of oxidation. It is explanatory drawing for demonstrating the state of the surface of the deposition prevention film | membrane 111 in the process of oxidation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a configuration of an atomic layer growth apparatus according to an embodiment of the present invention. In this atomic layer growth apparatus, first, the apparatus main body 101 includes a film formation chamber 102 in which a substrate (not shown) to be formed is placed. A substrate table 103 on which a substrate is placed is provided inside the film formation chamber 102, and the substrate table 103 incorporates a heating mechanism 104 for heating the substrate. Further, the apparatus main body 101 includes a gas inlet 105 for introducing a source gas into the film forming chamber 102 and a gas inlet 106 for introducing oxygen gas into the film forming chamber 102. Further, the apparatus main body 101 includes an exhaust port 107 connected to the inside of the film forming chamber 102.

  A high frequency generation source 108 is provided in the upper part of the film formation chamber 102, and a high frequency power supply unit 109 for supplying high frequency power is connected to the high frequency generation source 108. A source gas supply unit 151 for supplying an aluminum source gas to the film forming chamber 102 is connected to the gas inlet 105. An example of the aluminum source gas is trimethylaluminum (TMA) gas. The source gas for aluminum may be other organometallic compounds such as triethylaluminum (TEA).

  An oxidizing gas supply unit 161 that supplies oxygen gas to the film forming chamber 102 is connected to the gas inlet 106. Further, a vacuum pump (exhaust means) 110 that exhausts the inside of the film forming chamber 102 is connected to the exhaust port 107. In this embodiment, as will be described later, oxygen gas supplied from the oxidizing gas supply unit 161 is used as plasma at a high frequency supplied from the high-frequency generation source 108, and this oxygen gas plasma is used as the oxidizing gas. Therefore, in this case, it can be considered that the high-frequency generation source 108, the high-frequency power supply unit 109, and the oxidizing gas supply unit 161 constitute an oxidizing gas supply unit.

In addition, the atomic layer growth apparatus in the present embodiment includes a deposition prevention film 111 made of an organic resin and formed on the inner wall of the film formation chamber 102. The deposition preventing film 111 is made of an organic resin that is oxidized and vaporized by the above-described oxygen gas plasma (oxidation gas). For example, the organic resin is polyparaxylylene ([C ₆ H ₆ (CH ₂ ) ₂ ] _n ) Resin. The deposition prevention film 111 may be formed on an inner wall that is in contact with a space communicating with the film formation chamber 102, such as the inner walls of the gas inlet 105, the gas inlet 106, and the exhaust outlet 107.

  In the atomic layer growth apparatus according to the present embodiment configured as described above, one of the deposition preventing films 111 is formed by the action of oxygen gas plasma (oxidation gas) in the oxidation step of atomic layer growth of an aluminum oxide (alumina) film. By vaporizing the surface of the part, deposits due to the aluminum material deposited on the surface of the deposition preventing film 111 are removed.

  Hereinafter, the formation of an alumina film by atomic layer growth will be described in more detail. First, a glass substrate is placed inside the film formation chamber 102 of the atomic layer growth apparatus, and the vacuum pump 110 is operated to set the pressure in the film formation chamber 102 to about 2 to 3 Pa. In addition, the heating mechanism 104 is operated to heat the glass substrate to about 250 ° C. In addition, heating of a glass substrate is continued until a series of thin film formation is complete | finished.

  In this state, a source gas made of TMA is introduced into the film formation chamber 102, and the source gas is supplied onto the glass substrate. The source gas is supplied for about 1 second, for example. Thereby, an adsorption layer in which TMA molecules (organic compounds) as raw materials are adsorbed is formed on the glass substrate. In the supply of the source gas, the exhaust from the exhaust port 107 by the vacuum pump 110 may be continued.

  Next, the introduction of the source gas into the deposition chamber 102 is stopped, and the source gas is discharged from the deposition chamber 102. For example, other than what is adsorbed (chemically adsorbed) on a glass substrate by introducing an inert gas (purge gas) such as nitrogen or argon while the inside of the film formation chamber 102 is exhausted by the vacuum pump 110 (adsorption layer) The excess gas is removed (purged) from the film formation chamber 102. In FIG. 1, a mechanism for introducing the purge gas is omitted.

  Next, for example, oxygen gas is introduced into the film formation chamber 102 and high frequency power is supplied from the high frequency power supply unit 109 to the high frequency generation source 108 disposed above the glass substrate in the film formation chamber 102. Plasma of the introduced oxygen gas is generated, and atomic oxygen is supplied to the surface of the adsorption layer. This plasma is generated for about 0.2 seconds. By this oxygen gas plasma (oxidizing gas), the adsorption layer adsorbed on the surface of the glass substrate is oxidized, and an aluminum oxide layer corresponding to one atomic layer of aluminum is formed on the surface of the glass substrate. Note that, for example, an inert gas such as argon may be introduced to introduce oxygen gas in a state where the pressure in the film formation chamber 102 is stabilized to some extent, and plasma may be generated in this state. In the supply of oxygen gas, the exhaust from the exhaust port 107 by the vacuum pump 110 may be continued.

  Next, the introduction of the oxygen gas into the film formation chamber 102 is stopped, and the oxygen gas is discharged from the film formation chamber 102. For example, oxygen gas is removed (purged) from the inside of the film formation chamber 102 by introducing a purge gas in a state where the inside of the film formation chamber 102 is exhausted by the vacuum pump 110.

  Next, a source gas is supplied onto the glass substrate, and a new adsorption layer is formed on the aluminum oxide layer. Next, the introduction of the source gas into the deposition chamber 102 is stopped, and the source gas is discharged from the deposition chamber 102. For example, surplus gas is removed from the deposition chamber 102 by introducing a purge gas while the inside of the deposition chamber 102 is evacuated by a vacuum pump.

  Next, for example, oxygen gas is introduced into the film formation chamber 102, and high frequency power is supplied to the high frequency generation source 108 in the same manner as described above to generate plasma of the introduced oxygen gas so that atomic oxygen is contained in the TMA molecular layer. The state is to be supplied to the surface. This plasma is generated for about 0.2 seconds. As a result, the adsorption layer adsorbed on the surface of the already formed aluminum oxide layer is oxidized, and a new aluminum oxide layer for one atomic layer of aluminum is formed on the surface of the aluminum oxide layer.

  As described above, an aluminum oxide layer is formed on the glass substrate by a series of basic steps of adsorption → source gas discharge → plasma oxidation → oxidation gas discharge. In this process of atomic layer growth, according to the present embodiment, the surface of the deposition prevention film 111 is also oxidized in the oxidation step using oxygen gas plasma. Here, since the source gas is introduced into the film formation chamber 102 in the adsorption step before the oxidation step, as shown in FIG. 2A, the surface of the deposition preventing film 111 is also formed from the aluminum source (TMA). The adsorbed molecule 201 is adsorbed.

  However, in the present embodiment, as described above, the surface of the deposition preventing film 111 is oxidized in the oxidation step, and the surface layer 111a is vaporized and removed as shown in FIG. 2B. As a result, the adsorbed molecules 201 adsorbed on the surface of the deposition preventing film 111 are also removed together with the removal of the surface layer 111a. It is considered that the adsorbed molecules 201 are vaporized along with the vaporization of the surface layer 111a due to oxidation. Further, it is considered that the adsorbed molecules 201 are desorbed from the deposition preventing film 111 due to the vaporization of the surface layer 111 a and are discharged from the film forming chamber 102 together with the oxidizing gas exhausted from the exhaust port 107.

  The above-described adsorption of the adsorbed molecules 201 to the deposition preventing film 111 in the adsorption step and the removal of the adsorbed molecules 201 in the oxidation step are repeated in the same manner as the atomic layer growth cycle. In other words, according to the present embodiment, it can be said that the inside of the apparatus is cleaned every time the oxidation step is performed in the cycle of atomic layer growth. As a result, according to the present embodiment, the formation of deposits serving as particle generation sources on the inner wall of the film forming chamber 102 is suppressed. As a matter of course, since the deposition preventing film 111 is not formed on the glass substrate, an aluminum oxide layer is formed on the glass substrate.

  Next, an experiment in which the deposition preventing film 111 made of polyparaxylylene resin is etched with oxygen gas plasma will be described. A sample in which a polyparaxylylene resin film is formed on a silicon substrate and an aluminum oxide layer is formed thereon is manufactured.

  In Sample 1, the substrate temperature condition is set to 250 ° C., and atomic layer growth of aluminum oxide is performed as described above. In the oxidation step, oxygen plasma with a plasma power of 3000 W is applied for 0.5 seconds. In Sample 1, by repeating the atomic layer growth cycle, an aluminum oxide layer having a thickness of 80 nm is formed in a region where the polyparaxylylene resin film is not formed. In contrast, an aluminum oxide layer is not formed in the region where the polyparaxylylene resin film is formed. In sample 1, the polyparaxylylene resin film decreases by 1.43 nm in one oxidation step.

  In Sample 2, the substrate temperature condition is set to 250 ° C., and atomic layer growth of aluminum oxide is performed as described above. In the oxidation step, oxygen plasma with a plasma power of 3000 W is applied for 0.2 seconds. In Sample 2, by repeating the atomic layer growth cycle, an aluminum oxide layer having a layer thickness of 12.3 nm is formed in a region where the polyparaxylylene resin film is not formed. In contrast, an aluminum oxide layer is not formed in the region where the polyparaxylylene resin film is formed. In sample 2, the polyparaxylylene resin film decreases by 0.74 nm in one oxidation step.

  As is clear from the above experimental results, it can be seen that deposit accumulation is suppressed in the region where the deposition prevention film 111 made of polyparaxylylene resin is formed.

  By the way, the deposition preventing film 111 made of polyparaxylylene resin can be formed by known vapor deposition polymerization (CVD). For example, a diparaxylylene-based dimer is vaporized by sublimation at 150 ° C., and this is heated to 650-700 ° C. under reduced pressure to produce a monomer radical. By introducing the monomer radical thus formed into the film formation chamber 102 at room temperature (23 to 25 ° C.), a polymer film of polyparaxylylene can be formed on the inner wall of the film formation chamber.

  In the above description, in the formation of aluminum oxide, the substrate heating temperature is set to 250 ° C. However, the present invention is not limited to this, and the atomic layer growth of aluminum oxide using TMA as a raw material has a substrate temperature in the range of room temperature to 300 ° C. You can do it. When the atomic layer growth of aluminum oxide is performed at room temperature, the heating mechanism 104 may be omitted. In the above description, plasma is generated in the film formation chamber 102 by the high-frequency generation source 108, but the present invention is not limited to this. For example, an antenna for generating plasma may be provided inside the film formation chamber 102. Alternatively, a parallel plate type plasma generation mechanism using the upper surface of the deposition chamber 102 and the substrate table 103 as electrodes may be used. Further, a well-known plasma generation mechanism having another configuration may be used.

  In the above description, the oxygen gas plasma is used as the oxidizing gas to oxidize the adsorption layer and the deposition preventing film 111. However, the present invention is not limited to this. For example, even if ozone generated by a well-known ozone generator is introduced into the film formation chamber 102 as an oxidizing gas and used, it is the same as in the above-described embodiment. In this case, a mechanism that generates (generates) ozone and supplies it to the film formation chamber 102 serves as an oxidizing gas supply unit. The adsorption layer and the deposition preventing film 111 can be oxidized by ozone.

  DESCRIPTION OF SYMBOLS 101 ... Apparatus main body, 102 ... Film-forming chamber, 103 ... Substrate stand, 104 ... Heating mechanism, 105 ... Gas introduction port, 106 ... Gas introduction port, 107 ... Exhaust port, 108 ... High frequency generation source, 109 ... High frequency electric power supply part DESCRIPTION OF SYMBOLS 110 ... Vacuum pump (exhaust means) 111 ... Deposition prevention film, 151 ... Raw material gas supply part, 161 ... Oxidation gas supply part

Claims (6)

A deposition chamber in which a substrate to be deposited is placed;
A source gas supply means for supplying an aluminum source gas to the film forming chamber;
An oxidizing gas supply means for supplying an oxidizing gas for oxidizing the adsorption layer formed on the substrate by supplying the source gas into the film forming chamber;
An exhaust means for exhausting the inside of the film forming chamber;
A deposition prevention film made of an organic resin and formed on the inner wall of the film forming chamber,
The atomic layer growth apparatus, wherein the deposition preventing film is oxidized and vaporized by the oxidizing gas. The atomic layer growth apparatus according to claim 1,
The atomic layer growth apparatus, wherein the organic resin is a polyparaxylylene resin. The atomic layer growth apparatus according to claim 1 or 2,
The atomic layer growth apparatus, wherein the oxidizing gas supply means is at least one of a plasma generating means for generating oxygen plasma as the oxidizing gas and an ozone generating means for generating ozone as the oxidizing gas. A first step of forming a deposition preventing film made of an organic resin on an inner wall of a film forming chamber in which a substrate to be formed is disposed;
A second step of supplying an aluminum source gas to the film formation chamber in which a substrate to be formed is disposed to form an adsorption layer made of the component of the source gas on the substrate;
A third step of exhausting the source gas from the film forming chamber, supplying an oxidizing gas to oxidize the adsorption layer, and forming an aluminum oxide layer on the substrate; and
The atomic layer growth method, wherein the deposition prevention film is made of an organic resin that is oxidized and vaporized by the oxidizing gas. In the atomic layer growth method according to claim 4,
The atomic layer growth method, wherein the organic resin is a polyparaxylylene resin. In the atomic layer growth method according to claim 4 or 5,
The atomic layer growth method characterized in that the oxidizing gas is at least one of oxygen plasma and ozone.

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