JPH0245921A - Ion implantation device - Google Patents

Abstract

PURPOSE:To effect ion implantation also for the rear of a wafer by rotating the whole of a platen of an ion implantation device or the platen and a wafer holder by providing a through-hole through the platen and further providing a rotary shaft on the platen or on the wafer holder. CONSTITUTION:An implantation chamber 2 of an ion implantation device includes a wafer holder 7 with a rotary shaft, and a platen 8 having a through- hole 9 therethrough. A wafer 1 carried from a pre-chamber is placed on the platen 8 and is held by the holder 7, permitting an edge portion thereof to be fixed. Upon ion implantation for the rear of the wafer 1, the platen 8 and the whole of the holder are rotated 180 deg. by a platen reversing rotary shaft fixed to the platen 8 and the holder 7. The second rotary shaft 13 for implantation for the rear is located at a position of the first rotary shaft 11, and the device is operated through the shaft 13 to ion implant the back surface of the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ion implanter, and more particularly to a mechanism of a portion of a wafer holder.

[Conventional technology]

As a gettering technology for impurities in semiconductor wafers,
Conventional methods include phosphorus diffusion treatment and blasting treatment using mechanical strain. ! Recently, attempts have been made to improve the yield of products by implanting ions such as Ar+ in the LSI manufacturing process to create a cleaner back strain material.

Gettering during the LSI manufacturing process is limited to phosphorus diffusion or ion implantation. The phosphorus diffusion method has the inconvenience of having to grow a film etc. on the wafer surface and then removing the film grown on the back surface to prevent the wafer surface from being contaminated with phosphorus. Therefore, if phosphorus diffusion is to be performed, several steps must be added. Another inconvenience is that it can only be done in the middle of a certain manufacturing process. On the other hand, the ion implantation method can be used in almost all manufacturing processes. Ion implantation into the backside of a wafer is attracting attention as a means of causing gettering inside the wafer to improve product yield.

However, in current general-purpose ion implantation equipment, the wafer sent by belt transport is placed on a silicon rubber-covered stand or a metal stand in the implantation chamber, and the wafer is held in a holder. , ions can only be implanted on one side of the wafer. Figures 5 and 6 below
This will be explained using figures.

The platen 3 in the injection chamber 2 is placed with the wafer IA whose surface has been coated with resist to protect the wafer surface facing down.
Mount using heavy set.

The wafer IA was fixed by a wafer holder 4 and rotated about 90 degrees with respect to the ion beam 6 via the rotation shaft 5, and impurity ions were implanted into the back surface of the wafer IA.

[Problem to be solved by the invention]

With the wafer holding mechanism of the conventional ion implanter described above, if ions are to be implanted into the back side of the wafer during the LSI manufacturing process, the patterned wafer surface must be protected by coating the entire surface with resist, etc. This adds the process of resist coating, which lengthens the product lead time. Another disadvantage is that even if the surface is coated with resist, belt conveyance cannot be used to protect the surface, and the wafer must be handled with tweezers.

Since a resist is used, a lot of resist residue adheres to the wafer holder and dust is generated in the vacuumed injection chamber. Furthermore, when the dose amount and beam current are large, the quality of the resist is altered, and there is also the drawback that the resist cannot be removed successfully in a subsequent process.

[Means to solve the problem]

The ion implantation apparatus of the present invention includes a platen having a through hole for exposing the back surface of the wafer, a wafer holder that holds the wafer placed on the platen, and an ion beam that exposes the front or back surface of the wafer to the ion beam. and a rotation shaft fixed to the platen or wafer holder for vertically rotating the platen or wafer holder.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a sectional view of a platen and a wafer holder according to a first embodiment of the present invention, and FIG. 2 is a perspective view thereof.

In the implantation chamber 2 of the ion implantation apparatus, a wafer holder 7 with a rotating shaft and a platen 8 provided with a through hole 9 are installed. The wafer 1 transported from the preliminary chamber is placed on a platen 8, and is sandwiched between a wafer holder 7 with a rotating shaft to fix the etched portion of the wafer. When implanting ions into the surface of the wafer 1, the first
about 90" to the ion beam 6 through the rotation axis 11 of
Rotate the entire platen and holder until the

When implanting ions into the back side of the wafer 1, the platen and holder are rotated 180° by the platen 8 and the rotating shaft 12 for reversing the platen fixed to the wafer holder 7 with a rotating shaft. Position the second rotary shaft 13 for backside injection, and then
Ions are implanted into the back surface of the wafer through the rotation shaft 13 of the wafer in the same manner as described above.

Therefore, compared to the conventional platen shown in FIGS. 5 and 6, by providing two new rotating shafts, ions can be implanted into the front and back surfaces of the wafer.

FIG. 3 is a sectional view of a platen and a wafer holder according to a second embodiment of the present invention, and FIG. 4 is a perspective view thereof.

As in the first embodiment, a wafer 1 is fixed to a wafer holder 4 and a platen 8A provided with a through hole 9.

This platen 8A is provided with a first rotating shaft 11 and a second rotating shaft 13 for injection into the front and back surfaces of the wafer.

When implanting ions onto the surface of the wafer 1, the first rotating shaft 1
After rotating the platen and holder as a whole until they are approximately 90° (clockwise) with respect to the ion beam 6 through the ion beam 1, the ions are implanted. When implanting ions into the back surface of the wafer 1, the entire platen and holder are rotated via the second rotating shaft 13 to approximately 90° (counterclockwise) with respect to the ion beam 6, and then the ions are implanted.

〔Effect of the invention〕

As explained above, the present invention provides a through hole in the platen of an ion implanter, and further provides a rotating shaft in the platen or wafer holder to rotate the platen or the entire platen and holder, thereby eliminating the need to apply resist. , and without damaging the wafer surface.
This has the effect of allowing ion implantation even to the back side of the wafer.

4... Wafer holder, 5... Rotating shaft, 6...
...Ion beam, 7...Wafer holder with rotating shaft, 8.8A...Platen, 9...Through hole, 11...
・First rotation axis, 12...Rotation axis for platen reversal, 1
3...Second rotation axis.

Claims (1)

[Claims] a platen having a through hole for exposing the back surface of the wafer; a wafer holder for holding the wafer placed on the platen; An ion implantation apparatus comprising: a platen for rotating the wafer holder; or a rotation shaft fixed to the wafer holder.