JP2978802B2 - Sputtering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sputtering apparatus for alternately sputtering a metal film and a nitride film of the same metal on a wafer as a semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, for example, in a process of forming a Ti film and a TiN film which are the same metal film, it is necessary to alternately form a Ti film and a TiN film in one sputtering chamber. is there. This can be accomplished by using two different sputtering apparatuses, which shortens the processing time. However, when a sputtering apparatus that has formed a metal film different from the Ti film and the TiN film is formed, a different type of foreign material deposited in the sputtering chamber is formed. In many cases, there is a quality problem that the metal film is peeled off and the particles of the metal contaminate the Ti film or TiN film.

Therefore, when a nitride film of the same metal is formed, the same sputtering apparatus is used, for example, by switching conditions from a Ti film to a TiN film or from a TiN film to a Ti film. However, since the sputtering immediately after switching is unstable due to drift of the apparatus, etc., in the sense of stabilizing the sputtering,
It was necessary to tentatively perform sputtering on an object other than a wafer, which is a product called a skipping.

FIGS. 2A and 2B are a schematic cross-sectional view and a schematic vertical cross-sectional view of a conventional example of a sputtering apparatus.
2. Description of the Related Art Conventionally, as shown in FIG. 2, this type of sputtering apparatus is provided with a shutter 14 provided in a chamber 15 and turned horizontally into a chamber 21 by rotation of a shaft 16. The shutter 14 is large enough to cover the entire surface of the holder 17 so that spatters do not adhere to the holder 17.

Further, the shutter 14 is turned to be positioned at two positions, so that the shutter 14 is in the closed position during a test fly-off, and is used for sputtering on other wafers. Is in the open position. In other words, with the shutter 14 in the closed position, the cathode 1 to which the high frequency and the DC voltage are applied is set.
8 and the target 19 are sputtered with Ti or TiN to form a Ti film or TiN on the shutter 14.
The membrane had been deposited.

[0006]

In the conventional sputtering apparatus described above, a Ti film or TiN
The film accumulates, and eventually the film peels off to form particulate foreign matter, which may adhere to the wafer placed on the holder and cause a serious defect in quality. Therefore, conventionally, in order to avoid this, the shutter has been replaced after performing several flying operations.

[0007] However, there is a problem that a lot of time is wasted in exchanging the shutter with the chamber being in the atmosphere and then returning the chamber to a vacuum again.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sputtering apparatus which can replace a flying member without exposing the chamber to the atmosphere and in which a deposit film of the flying member does not peel off.

[0009]

SUMMARY OF THE INVENTION A feature of the present invention is that a sputtering apparatus includes a holder on which a wafer, which is a circular semiconductor substrate, is placed, and a target which accommodates the holder and is arranged to face the holder. A shutter for mounting a circular pseudo wafer having a size large enough to cover the entire surface of the holder, and moving the shutter to a position covering the entire surface of the holder and a position exposing the entire surface of the holder. A positioning mechanism, a circular hole formed in the chamber wall corresponding to a position directly above the pseudo wafer of the shutter at a position where the holder is exposed, and a circular hole having a diameter substantially equal to the diameter of the circular hole. A cylindrical member with an open / close lid having an inner diameter and airtightly attached to the chamber via a gate valve; A mounting member for retaining the pseudo wafer in the cylindrical member, means for releasing the pseudo wafer from the mounting member, and the cylindrical member penetrating the pseudo wafer mounting surface of the shutter retracted from the holder. Means for placing the pseudo wafer, which is inserted into the member and released from the stop, and lowering the pseudo wafer and transferring the pseudo wafer to the mounting surface of the shutter.

It is preferable that a vacuum pump for evacuating the inside of the cylindrical member be provided. Further, it is preferable that a dish-shaped member which surrounds the pseudo wafer and is detachably attached to the mounting surface of the shutter on which the pseudo wafer is mounted.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a top view and a sectional view showing a sputtering apparatus according to an embodiment of the present invention. As shown in FIG. 1, this sputtering apparatus mounts a dummy wafer 20 having a circular shape for flying without breaking the vacuum of the chamber 12 on a shutter 9 at a position A in the chamber 12 or on the shutter 9. That is, a dummy wafer loading / unloading mechanism 1 capable of removing the dummy wafer 20 from the chamber 12 is provided.

The take-in / take-out mechanism 1 has a circular shape formed on the wall of the chamber 12 corresponding to the position directly above the dummy wafer 20 of the shutter 9 at the position A where the entire surface of the holder 17 is exposed, and into which the dummy wafer 20 can enter. Hole 12
and a cylindrical small chamber 1a having an opening and closing lid 2 having an inner diameter approximately equal to the diameter of the hole 12a and being airtightly attached to the chamber 12 via a gate valve 3, and a dummy wafer 20 inserted into the small chamber 1a. 5 that stays in the small chamber 1a, the solenoid 4 that retracts the shoes 5 to release the dummy wafer, and the mounting surface 9b of the dummy wafer 20 of the shutter 9 that is retracted from the holder 17 and enters the small chamber 1a. The push-up rod 6 is configured to place the dummy wafer 20 that has been inserted and the stoppage of which is released, and to move down and transfer the dummy wafer 20 to the mounting surface 9 b of the shutter 9.

Note that the rotation angle of the shutter 9 is
It is desirable that the position at which the shutter 9 transfers the dummy wafer is set to such an extent that the holder 17 is exposed so that the volume of 2 does not increase. It is desirable that the inner wall of the chamber 12 be manufactured so as to follow the outer shape of the shutter 9 so that the shutter 9 does not hit the inner wall. Further, a dish-like member 9a is provided around the mounting surface 9b of the dummy wafer 20 of the shutter 9 so as to surround the dummy wafer 20, so that the dummy wafer 20 and the film adhering therearound are peeled off so as not to fall into the chamber 12. . It is desirable that the dish-shaped member 9a can be attached to and detached from the shutter 9 so that it can be replaced.

On the other hand, although the small chamber 1a of the inlet / outlet mechanism 1 is smaller than the volume of the chamber 12, in order to make the vacuum evacuation time of the chamber 12 faster, the on-off valve 13 It is desirable to connect the rotary pump 8 which is a mechanical vacuum pump with the rotary pump 8.

Next, the operation of this sputtering apparatus will be described on the assumption that the formation of a Ti film is switched to the formation of a TiN film.
First, a wafer cassette containing a plurality of unprocessed wafers is loaded on an elevator table in a load lock chamber on the left side of the drawing (not shown). In parallel with this operation, the lid 2 of the small chamber 1a
And put the dummy wafer 20 on the protruding shoe 5. Next, the load lock chamber and the chamber 12 and the small chamber 1
a is evacuated. At this time, the leak valve 7 of the small chamber 1a is closed and the on-off valve 8 is opened to evacuate by a rotary pump.

Next, when the degree of vacuum in the chamber 12 and the small chamber 1a becomes substantially the same, a hole 12a is opened by the gate valve 3, and
The push-up rod 6 is raised to abut on the dummy wafer 20, the dummy wafer 20 is lifted from the shoe 5, the solenoid 4 is operated, and the shoe 5 is retracted. Then, the push-up rod 6 is lowered to transfer the dummy wafer 20 to the mounting surface 9 b of the shutter 9. Then, the gate valve 3 opens the hole 1
2a is closed to prevent unnecessary gas from entering the small chamber 1a. Alternatively, the on-off valve 8 may be closed, the leak valve 7 may be opened, and the small chamber 1a may be set to the atmosphere. Next, the shutter 9 on which the dummy wafer has been transferred is rotated by a rotary shaft 11 by a rotary solenoid 11.
Is rotated together with the rotation of, and moves from the position A to the position B.

Next, when the chamber 12 reaches a predetermined degree of vacuum, the shutter 9 is moved to the position B, and an etching gas containing nitrogen gas is introduced into the chamber 12 to perform a sputtering process, and a dummy wafer 20 just below the target is formed. Will be deposited. Then, the shutter 9 is turned to move from B to A.
Evacuate to the position. Next, wafers are sequentially transferred from the wafer cassette to the holder 17 by vertically moving the elevator and moving the robot arm to perform sputtering.

Conversely, when switching from the TiN film formation to the Ti film formation, the retracted shutter 9 is turned to the position B to perform the initial flying, and then the shutter 9 is moved. Is retracted to the position A, and an unprocessed wafer is sputtered.

Next, an operation in the case where the deposit film on the dummy wafer 20 is thickly deposited and is likely to be peeled off and the dummy wafer must be replaced will be described.

When replacing the chamber 12 while the chamber 12 is in a vacuum, first, the shutter 9 is set to the position A, the gate valve 3 is opened, the push-up rod 6 is raised, the dummy wafer 20 is put on the tip, and the small wafer 1a is put into the small chamber 1a. After the shoe 5 is projected by the solenoid 4, the push-up rod 6 is lowered to transfer the dummy wafer 20 to the shoe 5. And
After lowering the push-up rod to escape from the small chamber 1a,
The gate valve 3 is closed, the leak valve 7 is opened, the small chamber 1a is opened to the atmosphere, the lid 2 is opened, the dummy wafer 20 is taken out, and replaced with a new dummy wafer.

When the chamber 12 is in the atmosphere, the on-off valve 8 is closed, the leak valve 7 is opened to open the small chamber 1a to the atmosphere, and then the gate valve 3 is opened to place the dummy wafer 20 in the small chamber 1.
a, the lid 2 is opened, the lid 2 is opened, the dummy wafer 20 is taken out from the small chamber 1a, a new dummy wafer is placed on the front end of the push-up rod 6, the push-up rod 6 is lowered, and the shutter retracted from the holder 17. The dummy wafer 20 is mounted on the mounting surface 9b of the substrate 9.

As described above, the dummy wafer, which is a flying member, can be exchanged even when the chamber 12 is in a vacuum or in the air. The material of the dummy wafer may be any material, and it is essential that the dummy wafer has the same circular shape as the wafer to be processed.

[0024]

As described above, according to the present invention, there is provided a shutter having a size enough to cover a holder for mounting a dummy wafer for flying and mounting a wafer to be processed, and to mount the shutter on the holder. By providing a mechanism for moving and positioning the holder to a position where the holder is exposed and a small chamber through which a dummy wafer can be inserted and removed via a gate valve in a chamber directly above a position where the shutter is retracted from the holder, the vacuum in the chamber can be released or the shutter can be released. This eliminates the need for replacement, and reduces the number of stoppages of the apparatus, thereby improving the operation rate of the apparatus.

Further, by providing the dish-shaped member around the dummy wafer placed on the shutter, the substance peeling off the deposit film does not fall into the chamber, and the quality defect that has occurred conventionally has been eliminated. Was.

[Brief description of the drawings]

FIG. 1 is a top view and a cross-sectional view illustrating a sputtering apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view and a schematic vertical cross-sectional view of a conventional example of a sputtering apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Take-in and take-out mechanism 1a Small chamber 2 Lid 3 Gate valve 4 Solenoid 5 Shoe 6 Push-up rod 7 Leak valve 8 On-off valve 9, 14 Shutter 9a Plate member 9b Mounting surface 10 Rotating shaft 11 Rotary solenoid 12, 15 Chamber 12a Hole 13 Piping 16 Shaft 17 Holder 18 Cathode 19 Target 20 Dummy wafer

Claims (3)

(57) [Claims] In a sputtering apparatus having a holder for mounting a wafer, which is a circular semiconductor substrate, and a target for accommodating the holder and disposed opposite to the holder, the sputtering apparatus has a size sufficient to cover the entire surface of the holder. A shutter for mounting a pseudo wafer having a size and a circular shape, a mechanism for moving and positioning the shutter to a position covering the entire surface of the holder and a position exposing the entire surface of the holder, and exposing the holder A circular hole formed in the chamber wall corresponding to a position directly above the pseudo wafer of the shutter at the position, and having an inside diameter approximately the same as the diameter of the circular hole and capable of receiving the pseudo wafer, and via the gate valve. A cylindrical member with an open / close lid that is hermetically attached to a chamber, and a mounting for retaining the pseudo wafer inserted into the cylindrical member in the cylindrical member A member, means for releasing the placement of the pseudo wafer on the mounting member, and insertion of the shutter retracted from the holder through the mounting surface of the pseudo wafer into the cylindrical member to release the retention. Means for placing the pseudo wafer and moving down to transfer the pseudo wafer to the mounting surface of the shutter. 2. The sputtering apparatus according to claim 1, further comprising a vacuum pump for evacuating the inside of the cylindrical member. 3. The sputter apparatus according to claim 1, further comprising a dish-shaped member which surrounds the pseudo wafer and is detachably attached to a surface of the shutter on which the pseudo wafer is mounted.