KR20080001613A - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

This invention makes it a subject to provide the substrate processing method which can remove the residue resulting from a hydrofluoric acid easily, HF gas toward the wafer W which has the thermal oxidation film 61 and the BPSG film 63. , The BPSG film 63 is selectively etched, and then NH ₃ gas is supplied toward the wafer W so that the H ₂ SiF ₆ of the residue 64 generated in accordance with the reaction between SiO ₂ and hydrofluoric acid is supplied. And NH ₃ gas to react to generate NH ₄ F and SiF ₄ , and further sublimate NH ₄ F.

Description

Substrate processing method and substrate processing apparatus {SUBSTRATE PROCESSING METHOD AND SUBSTRATE PROCESSING APPARATUS}

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows schematic structure of the substrate processing system provided with the substrate processing apparatus which concerns on 1st Embodiment of this invention.

FIG. 2 is a cross-sectional view of the second process module in FIG. 1, FIG. 2A is a cross-sectional view taken along the line II in FIG. 1, and FIG. 2B is a part A in FIG. 2A. It is an enlarged view.

3 is a flowchart showing a substrate processing method executed by the substrate processing system of FIG. 1.

4 is a graph showing the relationship between the type of oxide film and the etching rate.

5 is a flowchart illustrating a substrate processing method executed by the substrate processing system of FIG. 1.

It is a top view which shows schematic structure of the substrate processing system provided with the substrate processing apparatus which concerns on 2nd Embodiment of this invention.

FIG. 7: is sectional drawing of the 2nd process module in FIG. 6, FIG. 7 (A) is sectional drawing along the line II-II in FIG. 6, and FIG. 7 (B) is in FIG. Magnification of Part B.

8 is a flowchart illustrating a substrate processing method executed by the substrate processing system of FIG. 6.

FIG. 9 is a cross-sectional view illustrating a modification of the second process module of FIG. 7.

Explanation of symbols for main parts of the drawings

W: wafer 10, 77: substrate processing system

11: 1st process easy 12, 65: 2nd process easy

34: second process module 38: chamber

39: mounting table 40: shower head

43: lower gas supply part 44: upper gas supply part

60: silicon substrate 61: thermal oxide film

62: polysilicon film 63: BPSG film

64: residue 68: third process module

74: stage heater

TECHNICAL FIELD This invention relates to a substrate processing method and a substrate processing apparatus. Specifically, It is related with the substrate processing method which processes the board | substrate with which the oxide film containing a thermal oxidation film and an impurity was formed.

BACKGROUND ART A wafer (substrate) for a semiconductor device having a thermal oxide film formed by a thermal oxidation process and an oxide film containing impurities formed by a CVD process or the like, such as a BPSG (Boron Phosphorous Silicate Glass) film, is known. The BPSG film is formed so as to partially expose the polysilicon film on the polysilicon film, and functions as a hard mask when etching the polysilicon film. In addition, the thermal oxide film constitutes a gate oxide film.

In such a substrate, it is desired to selectively remove (etch) the BPSG film without removing (etching) the thermal oxide film after etching the polysilicon film.

When etching the oxide film, a plasma of CF gas is usually used, but since the plasma of CF gas not only heats the BPSG film but also the thermal oxide film, it is difficult to secure a selectivity ratio of the BPSG film to the thermal oxide film, and thus the BPSG film is selectively selected. Cannot be etched.

On the other hand, an etching method using plasma without the HF gas, or mixed gas of HF gas and a H ₂ O gas, has been proposed (see, for example, Patent Document 1). In this method, an oxide film containing impurities can be preferentially removed by hydrofluoric acid generated by the combination of HF gas and H ₂ O. As a result, the BPSG film can be selectively etched.

[Patent Document 1] Japanese Unexamined Patent Publication No. 194-181188

However, when the BPSG film is etched using HF gas or a mixed gas of HF gas and H ₂ O gas, residues are generated by the reaction of SiO ₂ with hydrofluoric acid, and the residues are formed on the surface of the wafer for semiconductor devices. Attach to. This residue causes a defect such as a short circuit in the semiconductor device manufactured from the wafer.

An object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can easily remove residues due to hydrofluoric acid.

In order to achieve the above object, the substrate processing method according to claim 1 is a substrate processing method for treating a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities, wherein the HF gas is directed toward the substrate. And a cleaning gas supplying step of supplying a cleaning gas including at least NH ₃ gas toward the substrate to which the HF gas is supplied.

The substrate processing method of claim 2 is the substrate processing method of claim 1, wherein in the HF gas supply step, H ₂ O gas is not supplied.

The substrate processing method of claim 3 is the substrate processing method of claim 1, wherein the substrate has a silicon-containing layer formed on the first oxide film and covered with the second oxide film, and the second oxide film is And partially expose the silicon containing layer, wherein the silicon containing layer is etched prior to the HF gas supply step.

In order to achieve the above object, the substrate processing method according to claim 4 is a substrate processing method for treating a substrate having a first oxide film formed by thermal oxidation treatment and a second oxide film containing impurities, wherein the HF gas is directed toward the substrate. It characterized in that it has a HF gas supply step of supplying a, and a substrate heating step of heating the substrate supplied with the HF gas.

The substrate processing method of claim 5 is the substrate processing method of claim 4, wherein in the substrate heating step, the substrate is heated in an atmosphere of N ₂ gas.

The substrate processing method of claim 6 is the substrate processing method of claim 4, wherein the substrate is heated to 150 ° C. or higher in the substrate heating step.

In order to achieve the above object, the substrate processing apparatus according to claim 7 is a substrate processing apparatus for processing a substrate having a first oxide film formed by a thermal oxidation treatment and a second oxide film containing impurities, wherein the substrate processing apparatus comprises an HF. An HF gas supply device for supplying a gas, and a cleaning gas supply device for supplying a cleaning gas including at least NH ₃ gas toward the substrate supplied with the HF gas.

In order to achieve the above object, the substrate processing apparatus according to claim 8 is a substrate processing apparatus for processing a substrate having a first oxide film formed by a thermal oxidation treatment and a second oxide film containing an impurity, wherein the substrate processing apparatus includes an HF. An HF gas supply device for supplying a gas, and a substrate heating device for heating the substrate to which the HF gas is supplied are provided.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring drawings.

First, the substrate processing system provided with the substrate processing apparatus which concerns on 1st Embodiment of this invention is demonstrated.

1: is a top view which shows schematic structure of the substrate processing system provided with the substrate processing apparatus which concerns on this embodiment.

In FIG. 1, the substrate processing system 10 is the 1st process ship 11 which performs a plasma process on the wafer (henceforth a "wafer") W (substrate) for semiconductor devices, The said agent 2nd process ship 12 (substrate processing apparatus) arrange | positioned in parallel with 1 process ship 11 and performing predetermined process mentioned later on the wafer W in which the plasma process was performed in the 1st process ship 11 (substrate processing apparatus). ), And a loader module 13 as a rectangular common transfer chamber to which the first process ship 11 and the second process ship 12 are connected, respectively.

In addition to the first process ship 11 and the second process ship 12 described above, the loader module 13 includes a front opening Unified Pod (FOUP) 14 as a container for holding 25 wafers W. A third measuring unit for measuring the surface state of the wafer (W) and the orienter (16) for pre-aligning the position of the wafer (W) taken out from the pouf (14). The first and second IMS (Integrated Metrology System, Therma-Wave, Inc.) 17, 18 are connected.

The 1st process ship 11 and the 2nd process ship 12 are connected to the side wall which follows the longitudinal direction of the loader module 13, and are equipped with the three poop mounts 15 with the loader module 13 interposed. Are arranged to face each other, the orienter 16 is disposed at one end along the longitudinal direction of the loader module 13, and the first IMS 17 is disposed at the other end along the longitudinal direction of the loader module 13, and 2 IMS 18 is arranged in parallel with three pouf mounts 15.

The loader module 13 includes a scalar dual arm type conveyance arm mechanism 19 for conveying the wafer W disposed therein, and a wafer W disposed on the sidewall so as to correspond to each pouf placing table 15. It has three load ports 20 as an inlet of (). The transfer arm mechanism 19 takes out the wafer W from the pouf 14 mounted on the poop mounting table 15 via the load port 20, and takes out the taken out wafer W in a first process ( 11) It carries in and out to the 2nd process ship 12, the orienter 16, the 1st IMS 17, and the 2nd IMS 18. FIG.

The first IMS 17 is a monitor of an optical system, and has a stage 21 on which the wafer W loaded is placed, and an optical sensor 22 directed to the wafer W placed on the stage 21. The surface shape of the wafer W, for example, the film thickness of the polysilicon film, the CD (Critical Dimension) values of the wiring grooves and the gate electrodes are measured. The second IMS 18 is also an optical monitor, and has a stage 23 and an optical sensor 24 similarly to the first IMS 17.

The first process ship 11 includes a first process module 25 that performs a plasma treatment on the wafer W, and a link-type single pick that exchanges the wafer W with the first process module 25. The first load lock module 27 incorporating the 1st type conveyance arm 26 is provided.

The first process module 25 has a cylindrical processing chamber container (chamber) and an upper electrode and a lower electrode (not shown) disposed in the chamber, and the distance between the upper electrode and the lower electrode is a wafer ( W) is set at an appropriate interval for performing an etching process as a plasma process. In addition, the lower electrode has an ESC 28 in its government which chucks the wafer W by a coulomb force or the like.

In the first process module 25, a process gas containing a CF-based gas is introduced into the chamber to generate an electric field between the upper electrode and the lower electrode, thereby plasmating the introduced process gas to generate ions and radicals. The wafer W is etched with ions and radicals.

In the first process ship 11, the internal pressure of the loader module 13 is maintained at atmospheric pressure while the internal pressure of the first process module 25 is maintained in vacuum. Therefore, the 1st load lock module 27 is equipped with the vacuum gate valve 29 in the connection part with the 1st process module 25, and the standby gate valve 30 in the connection part with the loader module 13 is carried out. It is configured as a vacuum pre-conveying chamber whose internal pressure is adjustable.

Inside the first load lock module 27, a first conveyance arm 26 is provided in a substantially central portion, and a first buffer (on the first process module 25 side) is provided on the first process module 25 side than the first conveyance arm 26. 31 is provided, and the 2nd buffer 32 is provided in the loader module 13 side rather than the 1st conveyance arm 26. As shown in FIG. The 1st buffer 31 and the 2nd buffer 32 are arrange | positioned on the track | orbit which the support part (pick) 33 which supports the wafer W arrange | positioned at the front-end | tip part of the 1st conveyance arm 26 moves, By temporarily evacuating the plasma processed wafer W above the trajectory of the support part 33, the smoothness in the first process module 25 between the unetched wafer W and the etched wafer W is achieved. Enable replacement.

The 2nd process ship 12 is connected to the 2nd process module 34 which performs the predetermined | prescribed process mentioned later to the wafer W, and the said 2nd process module 34 through the vacuum gate valve 35, And a second load lock module 37 having a second transfer arm 36 of a link-type single pick type that exchanges wafers W with the second process module 34.

FIG. 2: is sectional drawing of the 2nd process module in FIG. 1, FIG. 2 (A) is sectional drawing along the line II in FIG. 1, and FIG. 2 (B) is A in FIG. It is an enlarged view of wealth.

In FIG. 2A, the second process module 34 includes a cylindrical processing chamber container (chamber) 38, a mounting table 39 of the wafer W disposed in the chamber 38, and a chamber ( Above the 38, the shower head 40 disposed to face the mounting table 39, a turbo molecular pump (TMP) 41 for exhausting gas, etc. in the chamber 38, and the chamber 38 and the TMP ( 41 has an Adaptive Pressure Control (APC) valve 42 as a variable butterfly valve disposed between 41 to control the pressure in the chamber 38.

The shower head 40 consists of a disk-shaped lower layer gas supply part 43 (clean gas supply device) and a disk-shaped upper layer gas supply part 44 (HF gas supply device), and the lower layer gas supply part 43 has an upper gas supply part ( 44) are stacked. In addition, the lower gas supply part 43 and the upper gas supply part 44 have the 1st buffer chamber 45 and the 2nd buffer chamber 46, respectively. The first buffer chamber 45 and the second buffer chamber 46 communicate with the chamber 38 through the gas vent holes 47 and 48, respectively.

The first buffer chamber 45 in the lower gas supply unit 43 of the shower head 40 is connected to an NH ₃ (ammonia) gas supply system (not shown). The NH ₃ gas supply system supplies NH ₃ gas (cleaning gas) to the first buffer chamber 45. The supplied NH ₃ gas is supplied into the chamber 38 through the gas vent 47.

Moreover, the 2nd buffer chamber 46 in the upper gas supply part 44 of the shower head 40 is connected to the HF gas supply system. The HF gas supply system supplies the HF gas to the second buffer chamber 46. The supplied HF gas is supplied into the chamber 38 through the gas vent 48. The upper gas supply 44 of the shower head 40 contains a heater (not shown), for example, a heating element. This heating element controls the temperature of the HF gas in the second buffer chamber 46.

In the shower head 40, as shown in FIG. 2 (B), the opening part into the chamber 38 in the gas vent holes 47 and 48 is formed in the shape which the edge part spreads. As a result, the NH ₃ gas or the HF gas can be efficiently diffused into the chamber 38. In addition, since the gas vent holes 47 and 48 have a narrow cross-sectional shape, residues generated in the chamber 38 are caused by the gas vent holes 47 and 48, and furthermore, the first buffer chamber 45 and the like. Backflow to the second buffer chamber 46 is prevented.

In the second process module 34, the side wall of the chamber 38 contains a heater (not shown), for example, a heating element. Thereby, the atmospheric temperature in the chamber 38 can be set higher than normal temperature, and the removal by hydrofluoric acid of the BPSG film 63 mentioned later can be accelerated | stimulated. In addition, the heating element in the sidewall prevents the residue generated during the removal by hydrofluoric acid of the BPSG film 63 from adhering to the inside of the sidewall by heating the sidewall.

The mounting table 39 has a refrigerant chamber (not shown) inside as a temperature control mechanism. The refrigerant chamber is supplied with a refrigerant having a predetermined temperature, for example, cooling water or garden liquid, and the temperature of the wafer W placed on the upper surface of the mounting table 39 is controlled by the temperature of the refrigerant.

Returning to FIG. 1, the 2nd rod lock module 37 has the conveyance chamber (chamber) 49 on the housing which accommodates the 2nd conveyance arm 36. As shown in FIG. In addition, the internal pressure of the loader module 13 is maintained at atmospheric pressure, while the internal pressure of the second process module 34 is maintained at or below atmospheric pressure, for example, almost vacuum. Therefore, the 2nd load lock module 37 is equipped with the vacuum gate valve 35 in the connection part with the 2nd process module 34, and the standby door valve 55 in the connection part with the loader module 13 is carried out. It is configured as a vacuum pre-conveying chamber whose internal pressure is adjustable.

Moreover, the substrate processing system 10 is equipped with the operation panel 56 arrange | positioned at the end in the longitudinal direction of the loader unit 13. The operation panel 56 has, for example, a display portion made of a liquid crystal display (LCD), which displays the operation status of each component of the substrate processing system 10.

By the way, Fig. 3 (A) the silicon substrate 60 on, a thermal oxide film 61 made of SiO ₂ formed by thermal oxidation process (first oxide film) as shown in the polysilicon film 62 (silicon-containing layer In order to selectively etch the BPSG film 63 in the wafer W on which the layer 62 and the BPSG film 63 (second oxide film) formed by the CVD process or the like are laminated, the HF gas as described above. Or a mixed gas of HF gas and H ₂ O gas without using plasma. On the other hand, the BPSG film 63 partially exposes the thermal oxide film 61 after etching the polysilicon film 62.

The present inventors conducted various experiments to further increase the selectivity ratio of the BPSG film 63 to the thermal oxide film 61, so that H ₂ O gas is not supplied and HF is not supplied under an environment in which almost no H ₂ O is present. When only gas is supplied toward the wafer W, as shown in the graph of FIG. 4, the etching rate of the BPSG film 63 is 500 nm / minute while the etching rate of the thermal oxide film 61 is kept at 5 nm / minute. Found to be able to increase up. That is, it was found that the selectivity ratio of the BPSG film 63 to the thermal oxide film 61 can be increased up to 1000. On the other hand, the inventors also found that the etching rate of the TEOS film can be increased to 20 nm / min under the above conditions.

Then, the present inventors earnestly studied the mechanism of realizing the high selectivity ratio, and inferred the hypothesis described below.

HF gas is hydrofluoric acid by combining with H ₂ O, the hydrofluoric acid invades and removes the oxide film. Here, in an environment where H ₂ O is hardly present, in order for HF gas to be hydrofluoric acid, it is necessary to be combined with water (H ₂ O) molecules contained in the oxide film.

Since the BPSG film 63 is formed by vapor deposition such as a CVD process, the film structure is coarse, and water molecules are easily adsorbed. Therefore, the BPSG film 63 contains water molecules to some extent. The HF gas reaching the BPSG film 63 is combined with this water molecule to form hydrofluoric acid. This hydrofluoric acid then invades the BPSG film 63.

On the other hand, since the thermal oxidation film 61 is formed by thermal oxidation treatment in an environment of 800 to 900 ° C, water molecules are difficult to adsorb because they do not contain water molecules at the time of film formation and the structure of the film is also compact. Therefore, the thermal oxide film 61 contains almost no water molecules. Even if the supplied HF gas reaches the thermal oxidation film 61, since no water molecules exist, it does not become hydrofluoric acid. As a result, the thermal oxide film 61 does not invade.

As a result, when only HF gas is supplied toward the wafer W without supplying the H ₂ O gas in an environment in which almost no H ₂ O exists, the selection of the BPSG film 63 for the thermal oxide film 61 is performed. The ratio can be increased to 1000.

By the way, when the BPSG film 63 is removed by hydrofluoric acid, SiO ₂ and hydrofluoric acid (HF) in the BPSG film 63 cause a chemical reaction represented by the following formula,

SiO ₂ + 4HF → SiF ₄ + 2H ₂ O ↑

SiF ₄ + 2HF → H ₂ SiF ₆

Residue (H ₂ SiF ₆ ) occurs.

In contrast, in this embodiment, NH ₃ is used to remove the residue. Specifically, by supplying NH ₃ gas toward H ₂ SiF ₆ , a chemical reaction represented by the following formula is caused,

H ₂ SiF ₆ + 2NH ₃ → 2NH ₄ F + SiF ₄ ↑

NH ₄ F (ammonium fluoride) and SiF ₄ (silicon tetrafluoride) are generated. NH ₄ F is a substance that is easy to sublimate, and if it is set slightly higher than normal temperature, it sublimes, and thus can be easily removed.

That is, in this embodiment, H ₂ SiF ₆ which is the residue of the reaction of SiO ₂ and hydrofluoric acid is removed through the reaction with NH ₃ and sublimation.

Next, the substrate processing method which concerns on this embodiment is demonstrated.

FIG. 5 is a flowchart showing a substrate processing method executed by the substrate processing system of FIG. 1.

First, the polysilicon film 62 is uniformly formed on the thermal oxide film 61, and the BPSG film 63 is formed on the polysilicon film 62 along a predetermined pattern to form the polysilicon film 62. The wafer W to be partially exposed is prepared. The wafer W is loaded into the chamber of the first process module 25 and placed on the ESC 28.

Next, a process gas containing a CF-based gas is introduced into the chamber, and an electric field is generated between the upper electrode and the lower electrode to plasma the process gas to generate ions and radicals, and the poly is exposed by the ions and radicals. An etching process is performed on the silicon film 62 (step S51). At this time, the polysilicon film 62 is etched to form via holes or trenches, and a part of the thermal oxide film 61 is exposed (Fig. 3 (A)).

Next, the wafer W is carried out from the chamber of the first process module 25 and carried into the chamber 38 of the second process module 34 via the loader module 13. At this time, the wafer W is placed on the mounting table 39.

Next, the pressure in the chamber 38 is set to 1.3 × 10 ¹ to 1.1 × 10 ³ Pa (1 to 8 Torr) by the APC valve 42 or the like, and the ambient temperature in the chamber 38 is set by a heater in the side wall. It sets to 40-60 degreeC. Then, HF gas is supplied from the upper gas supply unit 44 of the shower head 40 toward the wafer W at a flow rate of 40 to 60 SCCM (HF gas supply step) (step S52) (Fig. 3 (B)). On the other hand, at this time, almost no water molecules are removed in the chamber 38, and no H ₂ O gas is supplied into the chamber 38.

Here, HF gas reaching the BPSG film 63 is combined with water molecules contained in the BPSG film 63 to be hydrofluoric acid. This hydrofluoric acid invades the BPSG film 63, and as a result, the BPSG film 63 is selectively etched, but the residue 64 due to the reaction of SiO ₂ and the hydrofluoric acid in the BPSG film 63 It generates and deposits on the polysilicon film 62 or the exposed thermal oxide film 61 (FIG. 3C).

Next, after supplying the HF gas into the chamber 38 is stopped, NH ₃ gas is supplied from the lower gas supply part 43 of the shower head 40 toward the wafer W (cleaning gas supply step) ( Step S53) (FIG. 3D). At this time, the NH ₃ gas reacts with H ₂ SiF ₆ constituting the residue 64 to generate NH ₄ F and SiF ₄ . And the atmospheric temperature in the chamber 38 is set rather high than normal temperature, and NH ₄ F is sublimated (FIG. 3E).

Next, the wafer W is carried out from the chamber 38 of the second process module 34 to complete the present process.

According to the process of FIG. 5, HF gas is supplied toward the wafer W having the thermal oxide film 61 and the BPSG film 63, and NH ₃ gas is supplied toward the wafer W. The hydrofluoric acid generated from the HF gas selectively etches the BPSG film 63, but produces a residue 64 composed of H ₂ SiF ₆ . NH ₃ gas reacts with H ₂ SiF ₆ to generate NH ₄ F and SiF ₄ . NH ₄ F is easy to sublimate. Thus, the residue 64 can be removed through reaction and sublimation with NH ₃ . As a result, it is possible to easily remove the residue 64, which is comprised of H ₂ SiF _6.

In the process of FIG. 5, when HF gas is supplied toward the wafer W, almost no water molecules are removed in the chamber 38, and since H ₂ O gas is not supplied into the chamber 38. In the thermal oxide film 61 containing almost no water molecules, since the HF gas and the water molecules are hardly bonded and hardly hydrofluoric acid is generated, the thermal oxide film 61 hardly invades. Therefore, the BPSG film 63 can be selectively etched more reliably.

In the process of FIG. 5, the polysilicon film 62 is etched before the BPSG film 63 is removed by the supply of HF gas. Thereby, at the time of etching the polysilicon film 62, the BPSG film 63 can be used as a hard mask, and the polysilicon film 62 can be etched certainly in a desired shape.

In the process of FIG. 5, almost no water molecules are removed in the chamber 38, no H ₂ O gas is supplied into the chamber 38, and water contained in the BPSG film 63 in the wafer W is also included. The molecule is used and consumed in the reaction of SiO ₂ with hydrofluoric acid. Thus, the chamber 38 can be kept very dry. As a result, generation of particles due to water molecules and watermarks on the wafer W can be suppressed, and therefore, the reliability of the semiconductor device manufactured from the wafer W can be further improved.

On the other hand, in the process of FIG. 5, only NH ₃ gas is supplied into the chamber 38 at the time of removal of the residue 64, but the gas to be supplied is not limited thereto, and the gas other than the NH ₃ gas, for example, N ₂ It is also possible to supply a mixed gas with the gas.

In addition, in the processing of FIG. 5, selective etching of the BPSG film 63 and removal of the residue 64 can be performed in the same second process module 34. Therefore, the substrate processing system 10 can be miniaturized.

Next, the substrate processing system provided with the substrate processing apparatus which concerns on 2nd Embodiment of this invention is demonstrated.

This embodiment is basically the same as that of the first embodiment described above, and the configuration of the second process ship is only different from that of the first embodiment described above. Therefore, description of the same structure is abbreviate | omitted and only the structure and effect | action different from 1st Embodiment are demonstrated below.

6 is a plan view showing a schematic configuration of a substrate processing system having a substrate processing apparatus according to the present embodiment.

In FIG. 6, the substrate processing system 77 is the 2nd which performs the predetermined process mentioned later to the wafer W in which the plasma process was performed in the 1st process ship 11 and the 1st process ship 11. In FIG. The process ship 65 (substrate processing apparatus) and the loader module 13 are provided.

The 2nd process ship 65 is connected to the 2nd process module 66 which performs the selective etching process mentioned later to the wafer W, and the said 2nd process module 66 via the vacuum gate valve 67, The wafer W is provided with the 3rd process module 68 which performs the heat processing mentioned later, and the 2nd load lock module 37. FIG.

FIG. 7: is sectional drawing of the 2nd process module in FIG. 6, FIG. 7 (A) is sectional drawing along the line II-II in FIG. 6, and FIG. 7 (B) is in FIG. An enlarged view of part B of. On the other hand, the second process module 66 is basically the same as the second process module 34 in the above-described first embodiment, and the configuration of the shower head is the same as that of the second process module 34. It's different. Therefore, description of the same structure and operation is omitted.

In FIG. 7A, the second process module 66 has a shower head 69 disposed above the chamber 38. The shower head 69 has a disk-shaped gas supply part 70 (HF gas supply device), and the gas supply part 70 has a buffer chamber 71. The buffer chamber 71 communicates with the chamber 38 through the gas vent 72.

Moreover, the buffer chamber 71 in the gas supply part 70 of the shower head 69 is connected to the HF gas supply system. The HF gas supply system supplies the HF gas to the buffer chamber 71. The supplied HF gas is supplied into the chamber 38 through the gas vent 72. The gas supply part 70 of the shower head 69 contains a heater (not shown), for example, a heating element. This heating element controls the temperature of the HF gas in the buffer chamber 71.

In the shower head 69, similarly to the gas vent holes 47 (48) in the shower head 40, the openings into the chamber 38 in the gas vent holes 72 are formed in such a shape that their ends are spread. (FIG. 7B).

Returning to FIG. 6, the 3rd process module 68 is the process chamber container (chamber) 73 on a housing, the stage heater 74 (substrate heating apparatus) as a mounting base of the wafer W arrange | positioned in the said chamber 73. A buffer arm 75 disposed near the stage heater 74 to lift the wafer W placed on the stage heater 74 upwards, and an inert gas such as an N ₂ gas in the chamber 73. It has a gas introduction part (not shown) which introduces.

The stage heater 74 consists of aluminum with an oxide film formed on the surface, and heats the wafer W mounted by the heater which consists of a built-in heating wire etc. to predetermined temperature. In addition, the buffer arm 75 temporarily evacuates the wafer W subjected to the selective etching process upwards of the moving trajectory of the second transfer arm 37, whereby the second process module 66 or the third process module is provided. It is possible to smoothly replace the wafer W in 68.

In the substrate processing system 77, the internal pressure of the loader module 13 is maintained at atmospheric pressure, while the internal pressures of the second process module 66 and the third process module 68 are maintained at vacuum or below atmospheric pressure. Therefore, the 2nd load lock module 37 is equipped with the vacuum gate valve 76 at the connection part with the 3rd process module 68. FIG.

By the way, H ₂ SiF ₆ generated by the reaction between SiO ₂ and hydrofluoric acid is decomposed as shown below by heating.

H ₂ SiF ₆ + Q (heat energy) → 2HF ↑ + SiF ₄ ↑

Generates HF and SiF ₄ .

In this embodiment, H ₂ SiF ₆ , which is a residue of the reaction of SiO ₂ and hydrofluoric acid, is removed by decomposition by heating using decomposition of H ₂ SiF ₆ shown in the above formula.

Next, the substrate processing method which concerns on this embodiment is demonstrated.

8 is a flowchart illustrating a substrate processing method executed by the substrate processing system of FIG. 6.

First, step S51 in the process of FIG. 5 is executed. Subsequently, the wafer W is taken out from the chamber of the first process module 25 and loaded into the chamber 38 of the second process module 66 via the loader module 13. At this time, the wafer W is placed on the mounting table 39.

Next, step S52 in the process of FIG. 5 is executed to take out the wafer W from the chamber 38 of the second process module 66 and into the chamber 73 of the third process module 68. Bring in At this time, the wafer W is placed on the stage heater 74. And the wafer W mounted by the stage heater 74 is heated to predetermined temperature, specifically, 150 degreeC or more (substrate heating step) (step S81). In addition, the gas introduction portion introduces N ₂ gas into the chamber 73, and the introduced N ₂ gas forms a gas flow in accordance with the reduced pressure by the TMP 41. At this time, H ₂ SiF ₆ constituting the residue 64 is decomposed into HF and SiF ₄ by heating, and the decomposed HF and SiF ₄ are removed by gas flow.

Next, the wafer W is carried out from the chamber 73 of the third process module 68 to complete the present process.

According to the process of FIG. 8, HF gas is supplied toward the wafer W having the thermal oxide film 61 and the BPSG film 63, and the wafer W is heated. The hydrofluoric acid generated from the HF gas selectively etches the BPSG film 63, but produces residual water 64 composed from H ₂ SiF ₆ . The residue 64 is decomposed into HF and SiF ₄ by heating. Thus, the residue 64 can be removed by decomposition by heating. As a result, it is possible to easily remove the remainder (64) constructed from the H ₂ SiF _6.

In the process of FIG. 8, the supply of the HF gas to the wafer W and the heating of the wafer W were performed in separate process modules. However, these processes may be performed in one process module. Specifically, as shown in FIG. 9, a heater 78 is provided in the mounting table 39 in the second process module 66, and the BPSG film 63 is fluorinated in the chamber 38. After being removed, the wafer W is held on the mounting table 39 without being carried out from the chamber 38, and the wafer W is heated to 150 ° C. or more by the heater 78. H ₂ SiF ₆ generated by the reaction between SiO ₂ and hydrofluoric acid is decomposed at 150 ° C. or higher. Therefore, H ₂ SiF ₆ can be decomposed into HF and SiF ₄ by heating and can be reliably removed.

In the process of FIG. 8, since the N ₂ gas is introduced into the chamber 73 when the wafer W is heated, a gas flow is generated, the decomposed HF and SiF ₄ are rolled up in the gas flow to be surely removed. Can be.

In each of the above-described embodiments, the BPSG film 63 is selectively etched, but the oxide film selectively etched is not limited to this, and may be an oxide film containing at least more impurities than the thermal oxide film 61. A TEOS (Tetra Ethyl 0rtho Silicate) film or BPS (Boron Silicate Glass) film may be used. In addition, the residue to be removed is not limited to H ₂ SiF ₆ , and the present invention can be applied as long as the residue generated when the oxide film is removed by hydrofluoric acid is removed.

Moreover, although what demonstrated two process ships arranged in parallel as the substrate processing system provided with the substrate processing apparatus which concerns on each embodiment, the structure of a substrate processing system is not limited to this. Specifically, a plurality of process modules may be arranged in tandem or may be arranged in a cluster.

In addition, the board | substrate to which the process of FIG. 5 and the process of FIG. 8 are performed is not limited to the wafer for semiconductor devices, Even if it is various board | substrates used for LCD, a flat panel display (FPD), etc., a photo mask, a CD board, a printed board, etc. good.

In addition, an object of the present invention is to supply a storage medium storing program codes of software for realizing the functions of the above-described embodiments to a system or an apparatus, wherein a computer (or CPU or MPU, etc.) of the system or apparatus is provided. This is also achieved by reading out and executing the program code stored in the storage medium.

In this case, the program code itself read out from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, a hard disk, a magneto-optical disk, a CD-ROM, a CD-R, a CD-RW, a DVD-ROM, a DVD-RAM, a DVD- Optical disks such as RW and DVD + RW, magnetic tapes, nonvolatile memory cards, ROMs, and the like can be used. Alternatively, program code may be downloaded over a network.

In addition, by executing the program code read out by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) or the like running on the computer is part of the actual processing based on the instruction of the program code. It also includes a case where all of the above is performed and the functions of the above-described embodiments are realized by the processing.

The program code read out from the storage medium is written to a function expansion board inserted into a computer or a memory provided in a function expansion unit connected to a computer, and then the expansion function is expanded based on the instruction of the program code. It includes a case where a CPU or the like provided in the expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

According to the substrate processing method of Claim 1 and the substrate processing apparatus of Claim 7, HF gas is supplied toward the board | substrate which has the 1st oxide film formed by the thermal oxidation process, and the 2nd oxide film containing an impurity, and the said board | substrate Toward the side, a cleaning gas containing at least NH ₃ gas is supplied. The hydrofluoric acid generated from the HF gas selectively etches the second oxide film, but produces a residue. NH ₃ gas reacts with the residue to produce a substance that is susceptible to sublimation. Thus, the residue can be removed through reaction and sublimation with NH ₃ . Thereby, the residue resulting from hydrofluoric acid can be removed easily.

According to the substrate processing method as set forth in claim 2, in the HF gas supply step, H ₂ O gas is not supplied, the first oxide film that contains almost no H ₂ O, HF gas and a H ₂ O is hardly combined HF Since this hardly occurs, the first oxide film is hardly etched. Therefore, the second oxide film can be selectively etched more reliably.

According to the substrate processing method of claim 3, the silicon-containing layer is etched before the HF gas is supplied. Thereby, at the time of etching a silicon containing layer, a 2nd oxide film can be used as a hard mask, and a silicon containing layer can be etched reliably to a desired shape.

According to the substrate processing method of Claim 4 and the substrate processing apparatus of Claim 8, HF gas is supplied toward the board | substrate which has the 1st oxide film formed by the thermal oxidation process, and the 2nd oxide film containing an impurity, and the said board | substrate is Heated. The hydrofluoric acid generated from the HF gas selectively etches the second oxide film, but produces a residue. The residue is decomposed by heating. Thus, the residue can be removed by decomposition by heating. Thereby, the residue resulting from hydrofluoric acid can be removed easily.

According to the substrate processing method of claim 5, the substrate is heated in an atmosphere of N ₂ gas. The N ₂ gas forms a gas stream, which transports the decomposed residues. Thus, residues due to hydrofluoric acid can be reliably removed.

According to the substrate processing method of claim 6, the substrate is heated to 150 ° C. or higher. Residues resulting from hydrofluoric acid decompose at 150 ° C and above. Therefore, the residue resulting from hydrofluoric acid can be removed more reliably.

Claims (8)

A substrate processing method for treating a substrate having a first oxide film formed by a thermal oxidation process and a second oxide film containing impurities, the method comprising: An HF gas supply step of supplying an HF gas toward the substrate, and And a cleaning gas supplying step of supplying a cleaning gas including at least NH ₃ gas toward the substrate supplied with the HF gas. The method of claim 1, In the HF gas supplying step, the H ₂ O gas is not supplied. The method according to claim 1 or 2, The substrate has a silicon containing layer formed on the first oxide film and covered with the second oxide film, the second oxide film partially exposing the silicon containing layer, And the silicon-containing layer is etched before the HF gas supply step. A substrate processing method for treating a substrate having a first oxide film formed by a thermal oxidation process and a second oxide film containing impurities, the method comprising: An HF gas supply step of supplying an HF gas toward the substrate, and And a substrate heating step of heating the substrate supplied with the HF gas. The method of claim 4, wherein In the substrate heating step, the substrate is heated in an atmosphere of N ₂ gas. The method according to claim 4 or 5, In the substrate heating step, the substrate is heated to 150 ° C or more. In the substrate processing apparatus which processes the board | substrate which has the 1st oxide film formed by the thermal oxidation process, and the 2nd oxide film containing an impurity, An HF gas supply device for supplying an HF gas toward the substrate, and And a cleaning gas supply device for supplying a cleaning gas including at least NH ₃ gas toward the substrate supplied with the HF gas. In the substrate processing apparatus which processes the board | substrate which has the 1st oxide film formed by the thermal oxidation process, and the 2nd oxide film containing an impurity, An HF gas supply device for supplying an HF gas toward the substrate, and And a substrate heating device for heating the substrate supplied with the HF gas.

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