JP3214182B2 - Film forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus, and more particularly to a wafer holder for a plasma enhanced chemical vapor deposition (CVD) apparatus.

2. Description of the Related Art In a semiconductor device manufacturing process, a vapor phase growth apparatus using plasma is often used as a film formation apparatus. In this device, if the adhesion between the wafer and the electrode on which the wafer is mounted is poor, abnormal discharge occurs and adversely affects the film thickness distribution. Therefore, it is necessary to improve the adhesion.

[0003]

2. Description of the Related Art In a conventional plasma CVD apparatus, in order to bring a wafer into close contact with an electrode, the wafer is held in close contact with pins (claws) or the like.

FIGS. 5A and 5B are explanatory views of a conventional wafer holder. In the figure, 1 is an electrode for holding a wafer, 2 is a wafer, and 3 is a pin. In this example, the wafer is held vertically by pins 3 on both sides of the electrode.

[0005]

FIGS. 6A and 6B are diagrams for explaining the problems of the conventional example. As shown in FIG. 6A, when the taper angle of the pin 3 is large, the adhesion of the wafer is improved, but the detachability of the wafer is deteriorated. In contrast, Fig. 6 (B)
As shown in (2), when the taper angle of the pin 3 is small, the removability of the wafer is improved, but the adhesion of the wafer is deteriorated, and abnormal discharge occurs in the plasma.

An object of the present invention is to improve the film thickness distribution by preventing abnormal discharge by improving the drawbacks of the conventional example and simultaneously improving both the detachability and adhesion of the wafer to the holder. I do.

[0007]

To solve the above problems, 1) a wafer holder for mounting a wafer and applying electric power;
The wafer holder is formed of a hollow conductor, a groove-shaped suction hole 5 is formed along a peripheral edge of the wafer at a position where the wafer contacts, and a suction port for vacuum-suctioning the hollow portion.
Or 2) the wafer holder 1 is vertically held in the film forming apparatus, and is provided with a pin 3 having a notch for holding the wafer when vacuum suction is not performed; The film forming apparatus according to 1), wherein the width of the cut is larger than the thickness of the wafer, or 3) a plurality of wafer holders 1 are arranged side by side with their main surfaces facing each other and spaced apart from each other. Suction port
4, the remaining wafer holder is connected to the second current-carrying conductor 8 through the suction port, and the first and second current-carrying conductors are connected to each other. And the above-mentioned hollow portion can be evacuated via both of the current-carrying conductors. .

[0008]

FIGS. 1A and 1B are diagrams illustrating the principle of the present invention. 1 (A) is a perspective view, FIG. 1 (B) is a side view of a pin, 1 is a wafer holder, 2 is a wafer, 3 is a pin for holding a wafer, 4 is a suction port, and 5 is a wafer suction port. .

The holder 1 of the present invention is provided with a suction hole at a portion where the inside is hollow and hits the wafer, and the wafer 2 can be brought into close contact with the holder 1 by vacuum suction from the suction port 4. As shown in FIG. 1B, the cross section of the pins is not tapered, but allows the wafer to be attached and detached with a margin in dimension.

[0010] When a film is formed using this holder, the following is performed. When a wafer is inserted into the apparatus, the wafer is held by pins 3 to prevent it from falling, and after entering a predetermined position, vacuum suction is performed to bring the wafer into close contact with the holder and then form a film.

As a result, the adhesion is improved and no abnormal discharge occurs. When processing under atmospheric pressure, there is a problem that the wafer is deformed if the vacuum pressure is too low. However, plasma processing is performed under reduced pressure (about 1 Torr), so the vacuum inside the holder is reduced. Even if the pressure is low, the wafer does not deform.

[0012]

2A and 2B are explanatory diagrams of an embodiment (1) of the present invention. This example is a batch type plasma CVD apparatus for processing a plurality of wafers at a time.

FIG. 2A is a perspective view, FIG. 2B is a side view, and FIG.
Is a hollow wafer holder made of carbon, etc., 3 is a pin for holding the wafer, 4 is a suction port, 5 is a suction hole formed in the wafer holder, and is formed in a circular shape so as to suck the peripheral portion of the wafer. 6 is a spacer for a wafer holder made of an insulator such as a ceramic, and 7 and 8 are connected to the holder via a suction port 4, inside which a vacuum suction path is formed and power is supplied to the wafer holder. The conducting conductor to be performed.

Every other wafer holder is connected to the current-carrying conductors 7 and 8. When RF power is applied during this period, plasma is generated between adjacent wafer holders. This example
Although the disk boat type in which a plurality of disk-shaped wafer holders are arranged and held has been described, the present invention can be applied to the plate type shown in FIG. 3 as in FIG.

FIG. 3 is an explanatory view of an embodiment (2) of the present invention. In the figure, a wafer holder 1 has a plate shape, holds a plurality of wafers by pins and vacuum suction, arranges a plurality of wafer holders facing each other, and holds the wafers as described in FIG. Generate plasma between the components.

Normally, a quartz tube is used as a processing chamber in a batch type apparatus. However, in order to improve the in-plane distribution of wafers, a vertical furnace in which a plurality of wafers are vertically arranged with the wafers facing each other is being processed. Is rotating the wafer. However, in the horizontal furnace as in the embodiment, since the wafer falls,
Conventionally, rotation was not possible. However, as in the present invention, since the inside of the plate is evacuated and the wafer is sucked, rotation becomes possible.

FIGS. 4A to 4C are explanatory views of the embodiment (3) of the present invention. This example is an example in which the present invention is applied to a single-wafer plasma CVD apparatus. In this case, since the wafer 2 is placed horizontally, no wafer holding pins are required.

FIG. 4A is a cross-sectional view of the apparatus, in which a wafer 2 is placed on an electrode 1 in a processing chamber 9 and RF power is applied between the electrode 1 and a counter electrode 10 to generate a plasma. . As shown in FIG. 4 (B), the electrode (wafer holder) 1 on which the wafer is placed has a circular suction hole 5 along the periphery of the wafer. FIG. 4C shows an example in which a suction hole 5A is provided in addition to the circumferential suction hole 5.

If there is any gap between the wafer and the electrodes during the vacuum operation, the gas flows from there to the back surface of the wafer to form a film, which adversely affects other processes. In view of this, in the embodiment, instead of a round suction hole which is usually used, a gas suction hole 5 which is formed in a circumferential shape is used to suppress gas wraparound.

Here, although the electrode 1 is separated into the outer periphery and the inner side, the electrode 1 is kept at the same potential and does not affect the generation of plasma.

[0021]

According to the present invention, both detachability and adhesion to the wafer holder can be simultaneously improved, abnormal discharge of the plasma CVD apparatus can be prevented, and the film thickness distribution within the wafer and between the wafers can be prevented. Could be better.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is an explanatory view of an embodiment (1) of the present invention.

FIG. 3 is an explanatory view of an embodiment (2) of the present invention.

FIG. 4 is an explanatory view of an embodiment (3) of the present invention.

FIG. 5 is an explanatory view of a wafer holder according to a conventional example.

FIG. 6 is an explanatory diagram of a problem of a conventional example.

[Explanation of symbols]

 1 Wafer holder 2 Wafer 3 Wafer holding pin 4 Suction port 5 Groove-shaped suction hole opened in wafer holder 6 Wafer holder spacer made of insulator 7 First conducting conductor 8 Second conducting conductor 9 Processing chamber 10 Counter electrode

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-225818 (JP, A) JP-A-4-360553 (JP, A) JP-A-55-123130 (JP, A) 148817 (JP, A) JP-A-63-37629 (JP, A) JP-A-63-67250 (JP, U) JP-A-63-178334 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) H01L 21/205 H01L 21/68

Claims (3)

(57) [Claims] 1. A wafer holder (1) for mounting a wafer and applying electric power, the wafer holder being formed of a hollow conductor, and being positioned along a peripheral edge of the wafer at a position where the wafer contacts the wafer holder. A film-forming apparatus, wherein a groove-shaped suction hole (5) is formed and a suction port (4) for vacuum-suctioning the hollow portion is provided. 2. The wafer holder (1) is vertically held in a film forming apparatus, provided with a pin (3) having a notch for holding the wafer when vacuum suction is not performed, and the width of the notch is provided. 2. The film forming apparatus according to claim 1, wherein the thickness is larger than the thickness of the wafer. 3. A plurality of said wafer holders (1) are arranged side by side with an interval therebetween and alternately connected to a first current-carrying conductor (7) through said suction port (4). Then, the remaining wafer holder is passed through the suction port to the second current-carrying conductor.
(8), so that power can be applied between the first current-carrying conductor and the second current-carrying conductor, and the hollow portion can be exhausted through both the current-carrying conductors. The film forming apparatus according to claim 1 or 2, wherein: