JPH04323820A - Ion implantation device - Google Patents

Abstract

PURPOSE:To prevent the deterioration in connection characteristic by removing a silicon oxide film by plasma etching in a load-lock chamber. CONSTITUTION:A silicon wafer is carried from a stage 1A on the load side in the order illustrated by an arrow. Processes are cut off from each other by doors 9A-9D and the doors 9A-9D are opened and closed each time the silicon wafer passes through. To be more specific, the silicon wafer, being started from the stage 1A on the load side, is carried to a load-lock chamber 2A to be evacuated. In the load-lock chamber 2A, a silicon oxide film is removed by a plasma etching device installed in the chamber 2A. After the specified period of time of oxide film eliminating process, the silicon wafer is carried to an ion implantation chamber 3 to be injected with ion. Then, the silicon wafer is carried to a stage 1B on the unload side. This is the end of the process. By this method, the knock-on of oxygen atoms, etc., is prevented at the time of ion implantation and the deterioration in connection characteristic is reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion implantation apparatus used in semiconductor device manufacturing processes.

0002

2. Description of the Related Art In recent years, ion implantation technology has come to play an important role in the manufacture of semiconductor devices because its characteristics can be controlled freely and accurately. In the Si semiconductor manufacturing process, ion implantation is generally performed in a high vacuum chamber (implantation chamber). Therefore, the ion implantation apparatus is equipped with a transfer section (end station section) for loading and unloading the Si wafer between atmospheric pressure and the implantation chamber.

FIG. 3 is a plan view showing an end station section of a general ion implantation apparatus. In the figure, 1A is a load-side stage for installing the Si wafer during introduction, 1B is an unload-side stage for installing the Si wafer during extraction, and 2A is a load-lock chamber for vacuum evacuation during introduction. , 2B is an unload lock chamber for evacuation during extraction, 3 is an injection chamber for ion implantation, 4 is a rotary pump for evacuation of the load lock chamber 2A, and 5 is for evacuation of the unload lock chamber 2B. a rotary pump; 6 is a rotary pump that evacuates the injection chamber 3;
7 is a diffusion pump that evacuates the injection chamber 3; 8 is a cryopump that evacuates the injection chamber 3; 9A
~9D is a door for shutting off pressure.

Next, the operation will be explained. The Si wafer is transferred from stage 1A on the loading side to stage 1 on the unloading side.
They are transported to B in the order of the arrows in FIG. Each route is blocked from each other by doors 9A to 9D,
Doors 9A to 9D are to be opened and closed when the Si wafer passes through. In order to transfer the Si wafer in the atmosphere to the injection chamber 3 in a high vacuum state, it is necessary to open the doors 9B and 9C without significantly lowering the degree of vacuum in the injection chamber 3. Therefore, the load lock chamber 2A or unload lock chamber 2B is evacuated for a short time, and the injection chamber 3
After reducing the pressure gradient to the injection chamber door 9B,
9C is to be opened.

[0005] Transfer of a Si wafer in a conventional ion implantation apparatus is performed in the following process. stomach. The Si wafer is placed on stage 1A on the load side. B. The door 9A of the load lock chamber 2A is opened, and the Si wafer is transferred to the load lock chamber 2A. C. The door 9A of the load lock chamber 2A is closed, and the rotary pump 4 performs vacuum evacuation. D. When the pressure in the load lock chamber 2A reaches the set value, the door 9B of the injection chamber 3 opens and the Si wafer is transferred to the injection chamber 3. Ho. Thereafter, the door 9B of the implantation chamber 3 is closed, and ions are implanted into the Si wafer. F. When the ion implantation is completed, the door 9C of the injection chamber 3 is opened, and the ion is transported to the unload lock chamber 2B, which has been evacuated by the rotary pump 5 in advance. to. When the door 9C of the injection chamber 3 is closed, the door 9D of the unload lock chamber is opened, and the Si wafer returns to the stage 1B on the unload side with atmospheric pressure.

[0006]

[Problems to be Solved by the Invention] The end station section of the conventional ion implantation apparatus is configured as described above, and only vacuum evacuation of each route was performed during the loading process of the Si wafer. Ions were implanted with a natural oxide film (SiO2) formed in the atmosphere. Therefore, there is a problem in that oxygen atoms knocked into the Si from the surface native oxide film during ion implantation induce secondary defects during annealing, deteriorating the bonding characteristics.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an ion implantation device that can reduce the knock-on phenomenon from the native oxide film during implantation.

[0008]

[Means for Solving the Problems] An ion implantation apparatus according to the present invention is provided with a device for removing a Si oxide film from a wafer in a load lock chamber.

[0009]

[Operation] The Si oxide film removal device of the ion implantation device according to the present invention removes the oxide film from the Si wafer after evacuation in the load lock chamber, so the Si wafer surface is less likely to be oxidized again than in the atmosphere. It becomes extremely small.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an end station portion of an ion implantation apparatus according to an embodiment of the present invention. In the figure, the same reference numerals as in FIG. 3 indicate the same or corresponding parts, and 10
is a plasma etching device that removes oxide films from Si wafers.

Next, the operation will be explained. The Si wafer is transferred from stage 1A on the loading side to stage 1 on the unloading side.
They are transported to B in the order of the arrows in FIG. Each path is blocked from adjacent paths by respective doors 9A to 9D, and the doors 9A to 9D are to be opened and closed when the Si wafer passes through.

FIG. 2 shows the process of transporting the Si wafer.
The process is carried out as shown in the flowchart shown in .

That is, starting from the stage 1A on the load side, the Si wafer is transferred to the load lock chamber 2A and evacuated (step 4A). Next, the Si oxide film is removed by the plasma etching device 10 provided in the load lock chamber 2A (step 4B).
. After the oxide film has been removed for a certain period of time, it is transported to the implantation chamber 3 (step 4C), and ion implantation is performed (step 4
D). Thereafter, the Si wafer is transferred to the unload lock chamber 2B (step 4E), and the Si wafer is transferred to the unload lock chamber 2B (step 4E), and
The conveyance route ends at B.

In this embodiment, step 4B is added to the Si wafer transfer process. In step 4B, the oxide film is removed after evacuation, so that the Si wafer surface is less likely to be oxidized again or have impurities attached to it than in the atmosphere. Therefore, the Si wafer is ion-implanted with the oxide film removed, which prevents the deterioration of bonding characteristics due to oxygen atoms knocked into the Si from the native oxide film during ion implantation, which has been a problem in the past. Can be reduced.

In the above embodiment, a plasma etching device was used as the device for removing the Si oxide film, but an ion etching device, a wet etching device using chemicals, etc. may also be used as the oxide film removal device. The same effects as in the embodiment are achieved.

[0016]

As described above, according to the present invention, since a device for removing a Si oxide film is provided in the load lock chamber of the end station part of the ion implantation device, oxygen atoms etc. during ion implantation are removed. This has the effect of preventing knock-on and reducing deterioration of bonding properties.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an end station portion of an ion implantation apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart of a Si wafer transfer route according to an embodiment of the present invention.

FIG. 3 is a plan view showing an end station section of a conventional ion implanter.

[Explanation of symbols]

1A Road side stage 1B Unload side stage 2A Load lock room 2B Unload lock room 3 Injection chamber 4 Rotary pump 5 Rotary pump 9A Door 9B Door 9C Door 9D door 10 Plasma etching equipment

Claims (1)

[Claims] Claim 1: In an apparatus for implanting required ions into a semiconductor wafer, an oxide film formed on the wafer is removed in a load lock chamber for preliminary evacuation of the wafer to be ion-implanted and conveyed to the implantation chamber. An ion implantation device characterized by being provided with a device.