Adhesion removal method and film formation method

Abstract

Provided are: an adhered substance removing method capable of removing, without disassembling a chamber, a selenium-containing adhered substance which is attached to the inner surface of a chamber or the inner surface of a pipe connected to the chamber; and a film forming method. A selenium-containing adhered substance which is attached to at least one among the inner surface of a chamber (10) and the inner surface of an exhaust pipe (15) connected to the chamber (10) is removed by reacting with a cleaning gas that contains a hydrogen-containing compound gas.

Description

Technical Field

[0001] The present invention relates to a method for removing deposits and a film forming method.

Background Art

[0002] In recent years, in the semiconductor field, semiconductor materials containing elements other than silicon (Si) have attracted attention. Examples of semiconductor materials containing elements other than silicon include semiconductor materials containing group III-V elements such as germanium (Ge) and indium gallium arsenide (InGaAs), and semiconductor materials containing metal chalcogenides. Although these semiconductor materials have the advantage of high mobility (mobility) compared to silicon materials, there are cases where film formation is difficult or the defect density at the interface between materials becomes high.

[0003] Therefore, in order to reduce the defect density at the interface between materials, a method of forming a passivation film using hydrogen selenide (H2Se) gas on a substrate such as germanium or molybdenum has been proposed (see, for example, Patent Document 1). In addition, as a method for forming a metal chalcogenide film, a method of treating a molybdenum oxide layer and a tungsten oxide layer with radicalized hydrogen selenide gas to form a molybdenum selenide layer and a tungsten selenide layer has been proposed (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the method of reducing the defect density at the interface between materials, since the reaction is carried out at a high temperature, deposits containing selenium generated by the decomposition of hydrogen selenide may adhere to the inner surface of the chamber where the reaction is carried out or the inner surface of the pipe arranged on the downstream side of the chamber. When a substrate such as a wafer is introduced into the chamber with deposits containing selenium adhering to the inner surface of the chamber or the inner surface of the pipe arranged on the downstream side of the chamber, there is a risk that selenium particles will adhere to the substrate such as the wafer when the inside of the chamber is evacuated and replaced with an inert gas. And when selenium particles adhere to the substrate, the performance of the manufactured semiconductor structure may deteriorate.

[0006] For example, Patent Document 3 discloses a technique for etching a chalcogen compound semiconductor film containing selenium using a plasma etching apparatus. In this technique, since selenium derived from the etching product adheres to the inner surface of the chamber, the adhered selenium is removed by plasma cleaning with a cleaning gas containing boron trichloride (BCl3) and chlorine (Cl2). In the technique disclosed in Patent Document 3, selenium is removed by reacting it with chlorine. However, since selenium chloride, which is a reaction product, is solid depending on the oxidation number of selenium, there is a problem that it re-adheres to another place inside the plasma etching apparatus or re-adheres to the pipe arranged on the downstream side of the plasma etching apparatus. Therefore, when deposits containing selenium chloride adhere to the inner surface of the chamber or the inner surface of the pipe arranged on the downstream side of the chamber, it is necessary to disassemble the chamber and perform cleaning.

[0007] An object of the present invention is to provide an adhesion removal method and a film formation method capable of removing deposits containing selenium adhering to the inner surface of a chamber or the inner surface of a pipe connected to the chamber without disassembling the chamber.

Means for Solving the Problems

[0008] To solve the above problems, one aspect of the present invention is as follows in [1] to [6]. [1] An adhesion removal method for removing an adhesion containing selenium adhering to at least one of the inner surface of a chamber and the inner surface of a pipe connected to the chamber by reacting the adhesion with a cleaning gas containing a hydrogen-containing compound gas. [2] The adhesion removal method according to [1], wherein the cleaning gas is brought into contact with the adhesion under the conditions of a temperature of 20°C or higher and 800°C or lower and a pressure of 20 Pa or higher and 101 kPa or lower. [3] The adhesion removal method according to [1] or [2], wherein the hydrogen-containing compound gas is at least one selected from the group consisting of hydrogen gas, hydrocarbon gas, and ammonia gas. [4] The adhesion removal method according to [1] or [2], wherein the hydrogen-containing compound gas is hydrogen gas.

[0009] [5] A passivation step of supplying a passivation gas containing a selenium-containing compound gas to a chamber in which a substrate is accommodated, reacting the substrate with the passivation gas, and forming a passivation film on the surface of the substrate, After performing the passivation step, an adhesion removal step of removing an adhesion containing selenium adhering to at least one of the inner surface of the chamber and the inner surface of a pipe connected to the chamber, and A film forming method in which the adhesion removal step is performed by the adhesion removal method according to any one of [1] to [4]. [6] The film forming method according to [5], wherein the selenium-containing compound gas is hydrogen selenide gas. [Advantages of the Invention]

[0010] According to the present invention, it is possible to remove an adhesion containing selenium adhering to the inner surface of a chamber or the inner surface of a pipe connected to the chamber without disassembling the chamber. [Brief Description of the Drawings]

[0011]

Figure 1

Embodiments for Carrying Out the Invention

[0012] An embodiment of the present invention will be described below. It should be noted that this embodiment shows an example of the present invention, and the present invention is not limited to this embodiment. In addition, various changes or improvements can be made to this embodiment, and forms with such changes or improvements can also be included in the present invention.

[0013] 〔First Embodiment〕 The first embodiment of the present invention is an embodiment of an adhesion removal method, and an adhesion containing selenium (hereinafter, may be simply referred to as "adhesion") adhering to at least one of the inner surface of the chamber and the inner surface of the pipe connected to the chamber is reacted with a cleaning gas containing a hydrogen-containing compound gas to remove it. Note that the hydrogen-containing compound gas and the cleaning gas do not contain selenium atoms.

[0014] When a reaction using selenium is carried out in the chamber, etc., an adhesion containing selenium may adhere to the inner surface of the chamber or the inner surface of the pipe connected to the chamber (for example, the supply pipe for the cleaning gas connected to the upstream side of the chamber and the exhaust pipe connected to the downstream side of the chamber). If the next reaction is carried out with the adhesion remaining attached, it may have an adverse effect on the reaction, so it is preferable to carry out the next reaction after removing the adhesion.

[0015] The adhesion removal method according to the first embodiment removes the adhesion by bringing the cleaning gas into contact with the adhesion and reacting selenium in the adhesion with the hydrogen-containing compound gas in the cleaning gas to generate hydrogen selenide gas, so that the adhesion adhering to the inner surface of the chamber or the inner surface of the pipe connected to the chamber can be removed without disassembling the chamber. Therefore, the adhesion can be easily removed.

[0016] The contact between the cleaning gas and the deposit is preferably carried out under the condition that the temperature is 20°C or higher and 800°C or lower, and more preferably under the condition that the temperature is 40°C or higher and 600°C or lower. If the temperature is 800°C or lower, in addition to the fact that hydrogen-containing compound gas in the cleaning gas and the generated hydrogen selenide gas are less likely to corrode metal materials such as stainless steel forming the chamber and piping, the reverse reaction in which the hydrogen selenide gas generated by the reaction between selenium in the deposit and the hydrogen-containing compound gas in the cleaning gas returns to selenium is less likely to occur. On the other hand, if the temperature is 20°C or higher, the reaction between selenium in the deposit and the hydrogen-containing compound gas in the cleaning gas tends to proceed.

[0017] Also, the contact between the cleaning gas and the deposit is preferably carried out under the condition that the pressure is 20 Pa or higher and 101 kPa or lower in absolute pressure, and more preferably under the condition that the pressure is 60 Pa or higher and 90 kPa or lower. If the pressure is 101 kPa or lower, problems are less likely to occur in the chamber and piping. For example, when the chamber is a reaction vessel of a film forming apparatus that forms a passivation film on the surface of a substrate by reacting the substrate and a passivation gas, since use under a reduced pressure environment is assumed, the pressure condition is preferably 101 kPa or lower. On the other hand, if the pressure is 20 Pa or higher, the reaction between selenium in the deposit and the hydrogen-containing compound gas in the cleaning gas tends to proceed.

[0018] The hydrogen-containing compound gas is a gas of a compound having a hydrogen atom, and further a gas having no selenium atom and halogen atom. For example, hydrogen gas (H2), hydrocarbon gas, and ammonia gas (NH3) can be mentioned. Among these, at least one gas selected from the group consisting of hydrogen gas (H2), methane gas (CH4), ethane gas (C2H6), propane gas (C3H8), butane gas (C4H 10 ) and ammonia gas (NH3) is preferable, and at least one of hydrogen gas and methane gas is more preferable.

[0019] Since hydrogen gas reacts with selenium at a temperature of 300 °C or higher under a pressure of 101 kPa, when the cleaning gas contains hydrogen gas, it is preferable to bring the cleaning gas into contact with selenium (deposits) at a temperature of 300 °C or higher and 800 °C or lower. When the cleaning gas contains hydrogen gas, in order to efficiently remove the deposits, it is preferable to remove the deposits while heating the inside of the chamber and the piping. In addition, since a temperature of 300 °C or higher is preferable to enhance the reactivity between methane gas and selenium, when the cleaning gas contains methane gas, it is preferable to bring the cleaning gas into contact with selenium (deposits) at a temperature of 300 °C or higher and 800 °C or lower.

[0020] The content ratio of the hydrogen-containing compound gas in the cleaning gas is not particularly limited as long as it is an amount sufficient to remove selenium (deposits), but it is preferably 5% by volume or more, more preferably 20% by volume or more, still more preferably 90% by volume or more, and particularly preferably 100% by volume. Components other than the hydrogen-containing compound gas contained in the cleaning gas are not particularly limited as long as they are gases of compounds having no selenium atoms, and examples thereof include inert gases such as nitrogen gas and argon gas.

[0021] The chamber is not particularly limited as long as it is formed of a material having resistance to hydrogen selenide, but preferably has a structure capable of reducing the pressure to a predetermined pressure. Examples of the material include aluminum having an anodized surface. Also, the piping connected to the chamber is not particularly limited as long as it is formed of a material having resistance to hydrogen selenide, but preferably has a structure capable of withstanding a predetermined pressure. For example, the deposit removal method according to the first embodiment can be preferably applied to a chamber provided as a reaction vessel in a semiconductor film forming apparatus and the piping connected to the chamber.

[0022] 〔Second Embodiment〕 The second embodiment of the present invention is an embodiment of a film formation method, which includes a passivation step of supplying a passivation gas containing a selenium-containing compound gas into a chamber in which a substrate is accommodated, reacting the substrate with the passivation gas, and forming a passivation film on the surface of the substrate, and an adherent removal step of removing an adherent containing selenium adhering to at least one of the inner surface of the chamber and the inner surface of a pipe connected to the chamber after the passivation step. The adherent removal step is performed by the adherent removal method of the first embodiment.

[0023] In the passivation step of forming a passivation film on the surface of the substrate using the passivation gas, adherents containing selenium may adhere to the inner surface of the chamber or the inner surface of a pipe (for example, a supply pipe for the passivation gas or the cleaning gas connected to the upstream side of the chamber, or an exhaust pipe connected to the downstream side of the chamber) connected to the chamber.

[0024] When the substrate is introduced into the chamber with adherents adhering to the inner surface of the chamber or the inner surface of the pipe, there is a risk that selenium particles may adhere to the substrate when the inside of the chamber is evacuated and replaced with an inert gas. And when selenium particles adhere to the substrate, the performance of the manufactured semiconductor structure may deteriorate. Also, if the next passivation step is performed with selenium particles adhering to the substrate, problems such as a decrease in the film formation rate and film quality of the passivation film may occur. Therefore, it is preferable to perform the next passivation step after removing the adherents.

[0025] The film formation method according to the second embodiment removes deposits by bringing a cleaning gas into contact with the deposits and reacting selenium in the deposits with a hydrogen-containing compound gas in the cleaning gas to generate hydrogen selenide gas. Therefore, it is possible to remove the deposits adhering to the inner surface of the chamber and the inner surface of the pipes connected to the chamber without disassembling the chamber. Thus, the removal of deposits can be easily performed. Further, in the case of the film formation method according to the second embodiment, since it is possible to suppress the adhesion of selenium particles to the substrate due to the removal of deposits, a semiconductor structure having excellent performance can be manufactured.

[0026] Note that in the film formation method according to the second embodiment, it is not necessary to always perform the deposit removal step every time the passivation step is performed. The deposit removal step may be performed each time the passivation step is performed a plurality of times. If the number of times the deposit removal step is performed is reduced with respect to the number of times the passivation step is performed, the utilization efficiency of the film forming apparatus can be improved.

[0027] The type of the passivation gas containing the selenium-containing compound gas is not particularly limited as long as it is a gas of a compound having selenium. However, hydrogen selenide gas is preferable because of its good passivation performance. The content ratio of the selenium-containing compound gas in the passivation gas is not particularly limited as long as it is an amount sufficient for forming the passivation film. However, it is preferably 1% by volume or more, more preferably 2% by volume or more, further preferably 10% by volume or more, and particularly preferably 100% by volume. The components other than the selenium-containing compound gas contained in the passivation gas are not particularly limited, and examples thereof include inert gases such as nitrogen gas and argon gas.

[0028] The type of material for forming the substrate is not particularly limited as long as it is a semiconductor material. Examples include materials containing elements such as silicon, germanium, III-V compounds, molybdenum, and tungsten. As for silicon, the silicon used for forming semiconductor elements is preferred, and examples include amorphous silicon, polysilicon, and single-crystalline silicon. For germanium, III-V compounds, molybdenum, and tungsten, those used for forming semiconductor elements are also preferred.

[0029] The pressure inside the chamber when forming the passivation film in the passivation process is not particularly limited, but it is preferably 1 Pa or more and 101 kPa or less, more preferably 10 Pa or more and 90 kPa or less, and even more preferably 100 Pa or more and 80 kPa or less.

[0030] The temperature of the substrate when reacting the substrate with the passivation gas in the passivation process is not particularly limited. However, in order to obtain high in-plane uniformity of the treatment of the substrate surface by the passivation gas, it is preferably 20°C or more and 1500°C or less, more preferably 50°C or more and 1200°C or less, and even more preferably 100°C or more and 1000°C or less.

[0031] The length of the passivation time in the passivation process is not particularly limited. However, considering the efficiency of the semiconductor element manufacturing process, it is preferably within 120 minutes. Note that the passivation time refers to the time from when the passivation gas is supplied to the chamber containing the substrate until the passivation gas in the chamber is exhausted by a vacuum pump or the like to finish the treatment of the substrate surface by the passivation gas.

[0032] The film forming method according to the second embodiment can be suitably applied to a semiconductor film forming apparatus for forming a passivation film on the surface of a substrate. The structure of this film forming apparatus is not particularly limited, and the positional relationship between the substrate accommodated in the chamber, which is a reaction vessel, and the piping connected to the chamber is also not particularly limited.

Examples

[0033] Examples and comparative examples are shown below to explain the present invention in more detail. (Example 1) Using the film forming apparatus 1 shown in FIG. 1, a passivation step of forming a passivation film on the surface of the substrate and an adhesion removal step of removing the deposits containing selenium were repeatedly performed. The film forming apparatus 1 includes a chamber 10 that performs a passivation step and an adhesion removal step, and a temperature adjustment device (not shown) that adjusts the temperature inside the chamber 10. Inside the chamber 10, a stage 11 for supporting the sample 20 is provided. As the sample 20, a silicon substrate on which a 150 nm thick silicon oxide film was formed, and further a 80 nm thick molybdenum film was formed thereon was used.

[0034] To the chamber 10, on its upstream side, a passivation gas supply pipe 12 for supplying a passivation gas containing a selenium-containing compound gas to the chamber 10, a cleaning gas supply pipe 13 for supplying a cleaning gas containing a hydrogen-containing compound gas to the chamber 10, and an inert gas supply pipe 14 for supplying an inert gas to the chamber 10 are connected via valves 32, 33, and 34, respectively.

[0035] Also, to the chamber 10, on its downstream side, an exhaust pipe 15 for discharging the gas inside the chamber 10 to the outside is connected, and a vacuum pump 38 is connected to the downstream side of the exhaust pipe 15 via a valve 35. The pressure inside the chamber 10 is controlled by a pressure controller 37 that controls the valve 35.

[0036] Using such a film forming apparatus 1, a passivation process was first performed. The sample 20 was placed on the stage 11, and after reducing the pressure in the chamber 10 to less than 10 Pa, the temperature in the chamber 10 was raised to 800 °C. Then, the valve 32 was opened, and hydrogen selenide gas was supplied as a passivation gas into the chamber 10 from the passivation gas supply pipe 12 at a pressure of 101 kPa. The flow rate of the passivation gas at this time was 100 sccm, and the pressure in the chamber 10 when forming the passivation film on the surface of the sample 20 was 67 kPa. Note that sccm represents the flow rate (mL / min) at 0 °C and 101.3 kPa.

[0037] After introducing the passivation gas for 30 minutes and selenizing the surface of the sample 20 and forming a passivation film under the conditions of a temperature of 800 °C and a pressure of 67 kPa, the introduction of the passivation gas was stopped. Then, the inside of the chamber 10 was evacuated with the vacuum pump 38, and an inert gas was supplied into the chamber 10 from the inert gas supply pipe 14 to replace the inside of the chamber 10 with the inert gas. After that, the temperature in the chamber 10 was lowered to room temperature, and the sample 20 on which the passivation film was formed was taken out of the chamber 10.

[0038] Next, an adhesion removal process was performed using the film forming apparatus 1. After reducing the pressure in the chamber 10 from which the sample 20 was taken out to less than 10 Pa, the temperature in the chamber 10 was raised to 500 °C. Then, the valve 33 was opened, and hydrogen gas was supplied as a cleaning gas into the inside of the chamber 10 and the exhaust pipe 15 from the cleaning gas supply pipe 13. The flow rate of the cleaning gas at this time was 100 sccm, and the pressure in the chamber 10 when removing the adhesion was 67 kPa.

[0039] The introduction of the cleaning gas was carried out for 5 minutes, and the deposit was removed by reacting the deposit with hydrogen gas under the conditions of a temperature of 500 °C and a pressure of 67 kPa. Then, the introduction of the cleaning gas was stopped. Subsequently, the inside of the chamber 10 was evacuated with a vacuum pump 38, and an inert gas was supplied into the chamber 10 from the inert gas supply pipe 14 to replace the inside of the chamber 10 with the inert gas.

[0040] When the deposit removal process was completed, the passivation process was performed in the same manner as above, and a passivation film was formed on the new sample 20. Then, the deposit removal process was performed in the same manner as above. Such operations were repeated to produce a total of 100 samples 20 with a passivation film formed thereon.

[0041] (Example 2) A total of 100 samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the temperature inside the chamber 10 in the deposit removal process was 350 °C and the pressure was 100 Pa. (Example 3) A total of 100 samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the temperature inside the chamber 10 in the deposit removal process was 20 °C.

[0042] (Example 4) A total of 100 samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the temperature inside the chamber 10 in the deposit removal process was 800 °C. (Example 5) A total of 100 samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the pressure inside the chamber 10 in the deposit removal process was 20 Pa. (Example 6) A total of 100 samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the pressure inside the chamber 10 in the deposit removal process was 101 kPa.

[0043] (Example 7) One hundred samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the cleaning gas supplied from the cleaning gas supply pipe 13 in the deposit removal step was methane gas. (Example 8) One hundred samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that the cleaning gas supplied from the cleaning gas supply pipe 13 in the deposit removal step was ammonia gas.

[0044] (Comparative Example 1) One hundred samples 20 with a passivation film formed thereon were produced in the same manner as in Example 1, except that only the passivation step was repeated without performing the deposit removal step. For the samples 20 of Examples 1 to 8 and Comparative Example 1, the number of selenium particles adhering to the surface of the sample 20 was measured each time the passivation step of each sample 20 from the first to the 100th was completed. The measurement of the number of particles was performed using a wafer inspection apparatus Surfscan (registered trademark) 6240 manufactured by KLA-Tencor Corporation. The measurement results are shown in Table 1.

[0045]

Table 1

[0046] As can be seen from Table 1, in Comparative Example 1 where only the passivation step was repeated without performing the deposit removal step, as the number of passivation steps performed increased, that is, as the number of samples 20 with a passivation film formed thereon increased, the number of particles adhering to the sample 20 increased. At the 30th time, it was 2000 particles / m 2 or more, and at the 100th time, it was 11000 particles / m 2 or more.

[0047] On the other hand, in Examples 1 to 8 where the deposit removal step was performed after the passivation step, the number of particles adhering to the sample 20 was small. Even at the 100th passivation step, in Example 1, it was 100 particles / m2 is the degree, and in Example 2 it is 300 pieces / m 2 is the degree, and in other examples it is also 1000 pieces / m 2 or less. Thus, it was shown that by performing the deposit removal step, the passivation step can be repeatedly performed while keeping the number of adhering particles low without disassembling and cleaning the chamber.

Description of Symbols

[0048] 1 ··· Film forming apparatus 10 ··· Chamber 11 ··· Stage 12 ··· Pipe for supplying passivation gas 13 ··· Pipe for supplying cleaning gas 14 ··· Pipe for supplying inert gas 15 ··· Exhaust pipe 20 ··· Sample

Claims

1. Removing an adherent containing selenium adhering to at least one of the inner surface of a chamber and the inner surface of a pipe connected to the chamber by reacting it with a cleaning gas containing a hydrogen-containing compound gas, wherein the hydrogen-containing compound gas is at least one selected from the group consisting of hydrogen gas, hydrocarbon gas, and ammonia gas, the content ratio of the hydrogen-containing compound gas in the cleaning gas is 5% by volume or more, and a method for removing an adherent, wherein the cleaning gas is brought into contact with the adherent under the conditions of a temperature of 350°C or higher and 800°C or lower.

2. The method for removing an adherent according to Claim 1, wherein the cleaning gas is brought into contact with the adherent under the conditions of a pressure of 20 Pa or higher and 101 kPa or lower.

3. The method for removing an adherent according to Claim 1 or Claim 2, wherein the hydrogen-containing compound gas is hydrogen gas.

4. A passivation step of supplying a passivation gas containing a selenium-containing compound gas to a chamber in which a substrate is accommodated, reacting the substrate with the passivation gas, and forming a passivation film on the surface of the substrate, and an adherent removal step of removing an adherent containing selenium adhering to at least one of the inner surface of the chamber and the inner surface of a pipe connected to the chamber after the passivation step, characterized by comprising: a film forming method, wherein the adherent removal step is performed by the method for removing an adherent according to any one of Claims 1 to 3.

5. The film forming method according to Claim 4, wherein the selenium-containing compound gas is hydrogen selenide gas.

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