JPH05190471A - Treatment apparatus for forming film - Google Patents

Abstract

PURPOSE:To eliminate a source of occurrence of particles by preventing films from being formed on an undesired part of a treated substrate or removing the films. CONSTITUTION:A guide plate 30 for etching gas is fixed on the inner circumference of a ring support plate 32 having a sectional L shape. The guide plate 30 for etching gas extends along the outer circumference of a semiconductor wafer 12 and is not in contact with the semiconductor wafer 12, and a predetermined gap G between the guide plate 30 and the outer circumference of the semiconductor wafer 12 is formed. A gas pipe or a tube 34 for introducing an etching gas is piped in the lower part of a treating chamber 10 and a discharge vent 34a for the etching gas is located inside a shading plate 20. The etching gas out of the discharge vent 34a rises, and goes toward the outer circumference of the semiconductor wafer 12 along the rear of the semiconductor wafer 12. Then, the etching gas passes through the gap G while the gas is guided by the guide plate 30, and flows out of the surface side of the semiconductor wafer 12, and is fed to an exhaust vent 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for depositing a film on a substrate to be processed such as a semiconductor wafer to form a film.

[0002]

2. Description of the Related Art A film forming process is roughly classified into a process of directly oxidizing or nitriding a substrate to be processed to change the surface of the substrate to an oxide film or a nitride film, and a process of externally chemically treating the substrate. Alternatively, it is classified as a process of physically depositing a film. CVD (Chemical Vapor Doposition) and PVD (P
The film forming technique such as hysical vapor deposition is for performing the latter process. For example, in a CVD system,
A predetermined reaction gas is supplied while heating the substrate to be processed by an appropriate heater, and a reaction product or a decomposition product of the gas is deposited on the semiconductor wafer. Further, in a typical sputtering apparatus as a PVD apparatus, plasma is generated between a pair of electrodes facing each other, a target placed on the cathode is repelled by ions in the plasma, and a film is formed on a substrate to be treated placed on the anode. Deposit.

[0003]

From the viewpoint of improving the yield, it is desirable that the film formation is performed only on a predetermined portion of the substrate to be processed and not on other portions. For example, when the substrate to be processed is a semiconductor wafer, it is preferable that only the front surface (one surface) of the wafer is film-formed and not the end side surface or the back surface of the wafer.

However, the above CVD apparatus,
In a film forming apparatus such as a PVD apparatus, gas molecules or sputtered atoms inevitably enter or enter the end side surface or the back surface of a semiconductor wafer, so that a film is also formed there. The coating film thus formed on the end side surface and the back surface of the semiconductor wafer may come off due to contact, impact, etc. during unloading or transportation of the semiconductor wafer.
The peeled off film pieces become a large particle source and reduce the yield.

Therefore, conventionally, by pressing the outer peripheral edge of the semiconductor wafer with a ring-shaped cover, gas molecules and the like are prevented from entering the side surface and the back surface of the wafer, and a film is deposited on those portions. I was trying not to. However, since this method is a method of pressing a semiconductor wafer against a stage or the like with a strong pressing force, there is a problem that the wafer itself and the ring stage surface are scraped due to the contact and rubbing, and particles are generated from there. It was not an effective solution.

The present invention has been made in view of the above problems, and a non-contact method is used to prevent or remove film formation on an undesired portion of a substrate to be processed so that particles are not generated. An object is to provide a processing device.

[0007]

In order to achieve the above object, the film forming apparatus of the present invention is a film forming apparatus for depositing a film on a substrate to be processed by a chemical or physical method. An etching gas guide means is disposed so as to face a predetermined portion of the substrate to be processed with a gap therebetween, and an etching gas supply means for causing an etching gas to flow through the gap.

[0008]

When the etching gas flows into the gap during the film formation, the reaction gas or the like cannot enter the gap or cannot pass through the gap, so that the substrate portion to be processed in the gap and the portion beyond It is difficult for the coating film to be deposited on the treated substrate portion, and even if it is deposited, it is immediately removed by the etching gas and does not lead to the formation of the coating film. It is also possible to flow an etching gas into the gap after the film formation, and the unnecessary film formed near the gap is removed by the etching gas. As described above, in the present invention, film formation on an undesired portion is prevented without using a member such as a ring cover that directly contacts the substrate to be processed.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing the overall structure of a single-wafer CVD apparatus according to an embodiment, FIG. 2 is a plan view showing the structure of a wafer supporting section, and FIGS. 3 to 6 show various structural examples of an etching guide section. FIG.

In FIG. 1, the processing chamber 10 of the CVD apparatus according to this embodiment is a cylindrical chamber made of, for example, Al (aluminum), and a semiconductor wafer 12 as an object to be processed is arranged at the center of the processing chamber 10. .. This CVD apparatus does not use a susceptor (substrate installation table) but supports the semiconductor wafer 12 at three points in parallel with three pins arranged at 120 ° intervals, as will be described later.

A quartz plate 14 is attached to the center of the bottom surface of the processing chamber 10, and a halogen lamp 16 for heating is arranged below the quartz plate 14. During film formation, the semiconductor wafer 12 is heated by irradiating the back surface of the semiconductor wafer 12 with light from the halogen lamp 16 through the quartz plate 14. A ring-shaped support member 18 is fixed to the processing chamber 10 adjacent to the peripheral edge of the quartz plate 14.
A light-shielding plate 20 having a cylindrical shape is erected on the inner peripheral edge of 8. Further, a bottomed cylindrical light shielding plate 22 is attached to the bottom surface of the processing chamber 10 so as to surround the halogen lamp 16. The light of the halogen lamp 16 is efficiently supplied to the semiconductor wafer 12 by these light shielding plates 20 and 22, and at the same time, it is isolated from surrounding devices such as a temperature measuring device.

A gas inlet 2 is provided at the center of the upper surface of the processing chamber 10.
4 is provided, a reaction gas is introduced from the gas introduction port 24, and the introduced reaction gas is supplied to the surface of the semiconductor wafer 12 immediately below. Then, the gas generated in the film forming process, the remaining reaction gas, and the like are exhausted to the outside through the exhaust port 26 provided on the side wall of the processing chamber.

A gate valve 28 is provided on the side wall of the processing chamber 10 facing the exhaust port 26.
A wafer transfer mechanism such as a robot arm loads or unloads the semiconductor wafer 12 via the.

On the outer peripheral side of the semiconductor wafer 12, a ring-shaped etching gas guide plate 30 made of, for example, quartz is attached and fixed to the inner peripheral edge of an annular support plate 32 having an L-shaped cross section. This etching gas guide plate 30 is used for the semiconductor wafer 1
2 extends along the outer periphery of the semiconductor wafer 12, does not contact the semiconductor wafer 12, and has a predetermined gap G between the outer peripheral edge of the semiconductor wafer 12 and the semiconductor wafer 12.
Is formed. Further, a gas pipe or tube 34 for introducing the etching gas is drawn to the lower part of the processing chamber 10, and the gas discharge port 34 a is located inside the light shielding plate 20.

The gas pipe 34 is connected to an etching gas supply unit (not shown), and the etching gas is supplied at a predetermined flow rate from the etching gas supply unit during or after film formation. This etching gas is such as to be able to etch the film formed on the semiconductor wafer 12. For example, if the coating is tungsten based, ClF3
Gas is used as etching gas or ClF
3 gas diluted with N2 gas or Ar gas to a predetermined concentration is supplied as an etching gas.

The etching gas discharged from the gas discharge port 34a rises and travels along the back surface of the semiconductor wafer 12 toward the outer peripheral edge side of the semiconductor wafer 12 and the etching gas guide plate 30.
Through the gap G while being guided by the semiconductor wafer 12
To the exhaust port 26. At that time, in the gap G, the etching gas prevents the reaction gas coming from the opposite direction from entering, and when the film is deposited on the surface portion of the semiconductor wafer 12, the film is etched and removed.

Although FIG. 1 shows that the etching gas is supplied to the semiconductor wafer 12 from one gas discharge port 34a, the supply of the etching gas is made uniform in the circumferential direction of the semiconductor wafer 12. Like, for example, 1
You may provide three gas discharge ports at intervals of 20 degrees.

An annular support plate 3 is provided outside the cylindrical light shield plate 20.
6 is provided, and as shown in FIG.
The base end portions of four pusher pins 38 arranged at 0 ° intervals are fixed. When loading or unloading the semiconductor wafer 12, the supporting plate 36 is moved up to the position indicated by the dotted line 36 'by an elevating mechanism (not shown), so that each pusher pin 38 is moved up to the position indicated by the dotted line 38', and the pusher pins 38 are moved to and from the wafer transfer mechanism. The semiconductor wafer 12 is handed over.

Further, on the upper surface of the annular support member 18 at the bottom, as shown in FIG. 2, three support pins 4 are arranged at 120 ° intervals.
0 is erected vertically, and the semiconductor wafer 12 is horizontally supported by these three support pins 40. At least one of these three support pins 40 may be constituted by a thermocouple probe pin, and by doing so, the temperature of the semiconductor wafer 12 can be measured. It should be noted that in FIG. 2, the cylindrical light-shielding plate 20 corresponds to each pusher pin 3
8 and each support pin 40 are locally recessed inward.

Next, some structural examples of the etching gas guide plate 30 will be described with reference to FIGS. In the figure, the light shielding plate 20, the pusher pin 38, the support pin 40, and the like are omitted for ease of illustration.

First, in the example of FIG. 3, the inner diameter of the etching gas guide plate 30 is slightly larger than the outer diameter of the wafer 12 so as to face the end side surface 12a of the semiconductor wafer 12 with a gap G therebetween. .. According to this configuration, the etching gas sent from below passes through the narrow gap G with high pressure while being guided by the inner side surface 30a of the etching gas guide plate 30, and escapes to the front surface side of the semiconductor wafer 12.
As a result, the reaction gas is transferred to the end side surface 12 of the semiconductor wafer 12.
It cannot be turned to a or the back surface side, and it becomes difficult to deposit on those portions. Further, even if it is deposited, it is immediately removed by the etching gas. This configuration example is particularly effective in preventing film formation on the end side surface 12a of the semiconductor wafer 12.

In the example of FIG. 4, the etching gas guide plate 30 is arranged below the wafer 12 so as to face the peripheral edge portion 12b of the back surface of the semiconductor wafer 12 with a gap G therebetween. According to this configuration example, the etching gas passes through the narrow gap G with high pressure while being guided by the inner peripheral edge portion 30b of the upper surface of the etching gas guide plate 30, and the semiconductor wafer 12
Escape to the surface side of. As a result, the reaction gas cannot flow to the back surface side of the semiconductor wafer 12, and the film is less likely to be deposited on the back surface side. Even if it is deposited, it is immediately removed by the etching gas. This configuration example is suitable for preventing film formation on the back surface of the semiconductor wafer 12.

In the example of FIG. 5, the end side surface 1 of the semiconductor wafer 12 is shown.
2a and the back surface peripheral portion 12b have gaps G1 and G2, respectively.
The inner surface of the etching guide plate 30 is formed in a step shape so as to face each other. According to this configuration example, the etching gas is the step portion 30 of the etching gas guide plate 30.
The semiconductor wafer 12 passes through the gap G while being guided by c.
Escape to the surface side of. As a result, the reaction gas is prevented from entering the end side surface of the semiconductor wafer 12 and flowing into the back surface side. Even if it is deposited there, it is immediately removed by the etching gas. This configuration example is effective in simultaneously preventing film formation on the end side surface 12a and the back surface of the semiconductor wafer 12.

In the example of FIG. 6, the end side surface 1 of the semiconductor wafer 12 is shown.
2a and the peripheral portion 12c of the surface have gaps G1 and G3, respectively.
The inner surface of the etching guide plate 30 is formed in a stepped shape so as to face each other with a gap. According to this configuration example, the etching gas is the step portion 30d of the etching gas guide plate 30.
Since the reaction gas escapes to the surface side of the semiconductor wafer 12 through the gap G while being guided to, the reaction gas is prevented from entering the peripheral portion 12c of the surface of the semiconductor wafer 12, and even if the reaction gas is deposited there, it is immediately removed by the etching gas. To be removed. This configuration example is effective in simultaneously preventing film formation on the peripheral edge portion 12c and the end side surface 12a of the surface of the semiconductor wafer 12.

As described above, in the CVD apparatus of this embodiment, the etching gas is caused to flow in the gap G between the outer peripheral edge of the semiconductor wafer 12 and the etching gas guide plate 30 during or after the film formation. The film formation on the outer peripheral edge portion or the back surface of the semiconductor wafer 12 can be effectively removed. Since no film formation preventing member that directly contacts the semiconductor wafer 12 unlike the conventional ring cover is used, no particles caused by the contact are generated.

Various modifications can be made in addition to the above-mentioned configuration examples shown in FIGS. For example, in the above embodiment,
Although the etching gas guide plate is configured to face the outer peripheral edge portion of the semiconductor wafer 12 with a gap, the present invention is not limited to this, and faces the arbitrary portion of the substrate to be processed with a gap. It can also be configured to do so.

Further, in the above embodiment, the semiconductor wafer 12
Is supported at three points by three support pins 40, and light from the halogen lamp 16 is transmitted through the quartz plate 14 to the semiconductor wafer 1.
2 was irradiated and heated, but it is also possible to use a susceptor. In that case, rather than placing the semiconductor wafer directly on the susceptor, it is better to support the semiconductor wafer by separating it via a ring or a pin and to transfer the heat from the susceptor to the semiconductor wafer by radiating the etching gas guide plate. The configuration can be simplified.

Although the above embodiment relates to the CVD apparatus, the present invention can be applied to other film forming processing apparatuses such as a sputtering apparatus.

[0029]

As described above, according to the film formation processing apparatus of the present invention, the etching gas guide means is arranged so as to face a predetermined portion of the substrate to be processed with a gap, and the etching gas is guided into the gap. By flowing the gas, it is possible to prevent film formation on an undesired portion of the substrate to be processed by a non-contact method, so that there is no possibility of generation of particles and the yield can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing the overall configuration of a single-wafer CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing the configuration of a wafer support section in the apparatus of the embodiment.

FIG. 3 is a cross-sectional view showing a first configuration example of the etching gas guide plate in the example.

FIG. 4 is a cross-sectional view showing a second configuration example of the etching gas guide plate in the example.

FIG. 5 is a cross-sectional view showing a third configuration example of the etching gas guide plate in the example.

FIG. 6 is a cross-sectional view showing a fourth configuration example of the etching gas guide plate in the example.

[Explanation of symbols]

 10 Processing Chamber 12 Semiconductor Wafer 14 Quartz Plate 16 Halogen Lamp 20 Light-Shielding Plate 30 Etching Gas Guide Plate 32 Support Plate 34 Gas Pipe for Introducing Etching Gas 38 Pusher Pin 40 Support Pin

Claims (1)

[Claims] 1. A film forming apparatus for depositing a coating film on a substrate to be processed by a chemical or physical method, wherein an etching gas is arranged so as to face a predetermined portion of the substrate to be processed with a gap therebetween. A film forming apparatus comprising: a guide means and an etching gas supply means for supplying an etching gas to the gap.