JPS6244945A - Ion implanting apparatus - Google Patents

Abstract

PURPOSE:To obtain an ion implanting apparatus with high yield rate by providing a vacuum bake device which bakes, in a vacuum atmosphere, a treatment workpiece before it is subjected to an ion implantion. CONSTITUTION:When a wafer 4 is supplied to a vacuum bake device 3, a gate 9 for a loader is closed to actuate an auxiliary vacuum exhaust system 8, whereby the vacuum level in the vacuum bake device 3, namely a vacuum bake chamber, is made same with that in adjacent treatment chamber 16. During the process of generating a vacuum state, a heater heats the wafer 4 to bake a photoresist film on the main surface of the wafer 4 placed in rotating motion, and after the vacuum baking is completed, a vacuum generating gate 10 is opened. The wafer 4 on a stage 11 is placed by a transfer mechanism 27 on an auxiliary stage 32 located at the ascending position of the treatment workpiece supporting mechanism 23 in the treatment chamber 16. After that, the wafer 4 placed on said auxiliary stage is transferred on a receiving recess 36 and covered by a cover 34 its peripheral portion. Then, a desired ion is implanted into the main face of the wafer 4.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an ion implantation apparatus, and particularly to an ion implantation technique for implanting impurities into a workpiece that contains substances that generate gas and contaminate the processing atmosphere when heated. Concerning applied and effective techniques.

[Background technology]

In the manufacturing of semiconductor devices, when forming regions of each conductivity type on a semiconductor substrate (wafer), there is a device that can control impurity injection with high precision, such as the one published by the Industrial Research Association.
Electronic Materials J March 1983 issue, November 15, 1983
As described in Japanese publication, pages 81 to 86, ion implanters are often used.

Furthermore, as described in the above-mentioned literature, various problems arise due to the interaction between the ion beam and residual gas in the beam line during ion implantation.

Furthermore, since the wafer temperature increases due to ion implantation, forced cooling of the wafer may be required depending on the beam power.

By the way, when implanting impurities into the surface layer of the main surface of the wafer, a mask made of a photoresist film is previously formed on the main surface of the wafer by conventional photolithography, and the ion implantation is performed on the exposed areas not covered by the mask. Performed only on the wafer surface.

However, in conventional ion implantation equipment of this kind, the wafer becomes hot due to the implantation energy during ion implantation, which causes gas to be released from the photoresist film provided on the main surface of the wafer, which adversely affects device formation. There was found. In particular, the present inventor is aiming at increasing the diameter of wafers in order to improve productivity in semiconductor device manufacturing, but as the diameter of wafers becomes larger, it can be assumed that the amount of gas released will further increase. There are concerns that productivity will decline due to contamination.

[Purpose of the invention]

An object of the present invention is to provide an ion implantation device with high yield.

Another object of the present invention is to provide an ion implantation device with high productivity.

Another object of the present invention is to provide an ion implantation apparatus capable of implanting ions into large-diameter wafers.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Summary of the invention]

A brief overview of typical inventions disclosed in this application is as follows.

That is, the ion implantation apparatus of the present invention is equipped with a vacuum baking device, and a wafer having a photoresist film with a desired pattern on its main surface is subjected to baking treatment under a vacuum condition immediately before ion implantation. Therefore, the gas released from the photoresist film due to heating is once removed by this vacuum baking. Therefore, even if the wafer transferred to the processing chamber heats up due to the implantation energy during ion implantation, the generation of gas from the photoresist film will almost never occur, and the processing atmosphere will not be contaminated. Injection processing becomes possible, and yield direction -L can be achieved. In addition, in the ion implantation apparatus of the present invention, the wafer is subjected to vacuum baking treatment to prevent gas from being generated again due to heat generated during ion implantation. Since the injection effect is not affected, it is possible to process wafers with larger diameters, and productivity can be improved.

〔Example〕

FIG. 1 is a schematic plan view showing the conceptual structure of an ion implantation apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the wafer baking mechanism, and FIG. 3 is a cross-sectional view showing the ion implantation part. FIG. 4 is a partial plan view showing the wafer chuck state, and FIG. 5 is a flowchart showing the working process.

As shown in FIG. 1, the ion implantation apparatus of this embodiment has a main body 1, an ion irradiation device 2 connected to the main body 1, and a vacuum baking device 3 of the main body 1. It consists of a loader 5 that supplies a certain semiconductor substrate (wafer) 4, and an unloader 7 that carries out the wafer 4, which is stationary in the unloader reserve chamber 6 of the main body 1, out of the main body.

The vacuum baking device W3 has an airtight chamber structure in which a desired degree of vacuum can be maintained by a preliminary evacuation system 8, and also serves as a preliminary chamber for the loader. For this reason, this vacuum baking device 3 has a loader gate 9 on the outer wall side of the main body facing the loader 5, and also has a vacuum gate 10 on the inner wall portion located inside the main body 1. Further, as shown in FIG. 2, a stage 11 for supporting the wafer 4 is disposed within the vacuum baking apparatus 3. As shown in FIG.

A photoresist film 12 having a desired pattern is placed on the main surface of the stage 11, and is rotated by the rotation of the stage 11. In addition, the stage 1
A heater 13 consisting of an infrared lamp or the like is disposed above the stage 11, and heats the wafer 4 on the stage 11.
The photoresist film 12 on the main surface is baked.

The loader 5 includes a cartridge 14 that stores wafers 4 in multiple stages, and sequentially takes out the wafers 4 stored in the cartridge 14 from the lower stage, and
Conveyance mechanism 1 consisting of a belt conveyor that feeds and supplies
It consists of 5.

When the loader gate 9 of the vacuum baking device 3 is opened, the leading end of the transport mechanism 15 extends, and the leading end is positioned on the stage 11, as shown in FIG. There is. At this time, the stage 11 is temporarily lowered, and the wafer 4 is transported by the transport mechanism 15.
After being transferred and coming to rest, it rises to receive the wafer 4 that was on the transfer mechanism 15 onto the stage 11.

After the wafer 4 is supplied to the stage l1l-, the transport mechanism 15 moves backward and exits from the vacuum baking device 3 (vacuum baking chamber). In this vacuum baking device 3, after the transfer mechanism 15 has come out, the loader gate 9 is closed and the preliminary evacuation system 8 is activated to make the vacuum baking chamber the same as the processing chamber 16 of the main body 1. to a degree of vacuum. Note that during this vacuuming, the heater 13 is connected to the stage 1it-
The wafer 4 is heated. Further, the stage 11 rotates at a predetermined speed so that the wafer 4 is heated uniformly. Furthermore, in the vacuum baking device 3, baking is continued for a certain period of time even after the vacuum baking device 3 reaches a predetermined degree of vacuum, so that the gas from the photoresist film 12 on the main surface of the wafer 4 is removed. Allow sufficient divergence (baking is performed at 150° C. for several analyses),
After that, processing is performed so that no gas is released, that is, when the wafer 4 is transferred to the processing chamber 16 where ion implantation processing is performed, no gas is released.

The unloader preliminary chamber 6 has substantially the same structure as the vacuum baking device 3 except that the heater 13 and the stage 11 in the vacuum baking device 3 do not rotate. That is, the unloader preliminary chamber 6 has an unloader gate 1 on the outer wall portion of the main body 1 facing the unloader 7.
7, and also has a vacuum gate 18 on the inner wall side. Further, the unloader preparatory chamber 6 is opened to the unloader gate 1 by the operation of the preparatory vacuum evacuation system 19.
7 and the vacuum gate 18 are closed, a desired degree of vacuum is achieved. Further, in the center of this unloader preliminary chamber 6, a stage 20 having the same structure as the vacuum heave device 3 is disposed. Further, the unloader 7 includes a cartridge 21 that accommodates the wafers 4 in multiple stages, and a transport mechanism 22 that includes a belt conveyor that sequentially feeds the wafers 4 from the second stage to the bottom stage in conjunction with the upward movement of the cartridge 21. It consists of This transport mechanism 2
2 is when the unloader gate 17 is open;
The wafer 4 on the stage 11 enters the unloader preliminary chamber 6 and performs an operation opposite to that of the vacuum baking device W3.
is placed on the transport mechanism 22 and fed into the cartridge 21.

As described above, the main body 1 has the vacuum hake device 3 and the unloader preliminary chamber 6 on one side of the rectangular box, and is partitioned by the vacuum gate NO and the vacuum gate 18. The processing chamber 16 includes a processing object support mechanism 23. This processing object support mechanism 2
3 is disposed so as to face the exit port 25 of the ion beam 24 of the ion irradiation device 2 . Further, the processing chamber 16 is configured to have a desired degree of vacuum inside the processing chamber 16 by means of a vacuum exhaust system 26. Also,
Inside the processing chamber 16, the wafer 4 in the vacuum platform 3 can be transferred to the workpiece support mechanism 23, and the wafer 4 in the workpiece support mechanism 23 can be transferred to the unloader preliminary chamber 6. A transfer mechanism 27 is provided. This transfer mechanism 27 includes an arm 29 that rotates around a support shaft 28 at the rear end, and a mechanical chuck 30 provided at the tip of this arm 29. As shown in FIG. 3, the mechanical chuck 30 grips the wafer 4 by the clamping action of four claws 31, and also holds the auxiliary stage 32 of the workpiece support mechanism 23, which is movable up and down.
It is now possible to supply the above.

On the other hand, as shown in FIG. 3, the object support mechanism 23 includes the auxiliary stage 32 and
The support stage 33 receives the wafer 4 temporarily supported on the support stage 2 by the lowering operation of the auxiliary stage 32, and the cover 34 prevents the wafer 4 placed on the support stage 33 from falling off. . The support stage 33 is provided with a through hole 35 at the center of its main surface (upper surface) through which the auxiliary stage 32 can pass, and a housing recess 36 for accommodating the wafer 4. In addition, this support stage 33, as shown by the two-dot chain line in FIG.
It is designed to rotate forward and backward by 90 degrees around a rotating shaft 37 attached to one end, and the main surface of the evaporator 4 held on an upright support stage 33 is rotated 90 degrees forward and backward. The ion beam 24 from the ion irradiation device 2 is irradiated. Further, the cover 34 is provided to prevent the wafer 4 accommodated in the support stage 33 from falling off when the support stage 33 is in an upright state, and also to prevent ion implantation into the wafer 4. Furthermore, it must not overlap the support stage 33 when the wafer 4 is supplied or removed.

For this reason, the cover 34 is controlled to rotate in forward and backward directions around a support shaft 39 attached to a support plate 38 protruding from the support stage 33, so that when the wafer 4 is loaded or unloaded into the storage recess 36, Other than that, support stage 33
It is designed to overlap. Further, the cover 34 is provided with a through hole 40 that is slightly smaller than the diameter of the wafer 4. This through hole 40 faces the wafer 4 while overlapping the support stage 33, corresponds to an area other than the periphery of the wafer 4, and is an area through which the ion beam 24 passes.

In such an ion implantation apparatus, when ions are implanted into the main surface of the wafer 4 using the photoresist film 12 as a mask, the wafer 4 undergoes loading, vacuum hake, ion implantation, and unloading as shown in FIG. Go through each process. The wafer 4 is supplied from the cartridge 14 of the loader 5 to the stage 11 of the vacuum baking device 3 by a transport mechanism 15. When the wafer 4 is supplied to the vacuum baking device 3, the loader gate 9 is closed, and the preliminary vacuum evacuation system 8 is operated, so that the vacuum baking device 3, that is, the vacuum baking chamber, maintains the vacuum level of the adjacent processing chamber 16. The vacuum level will be the same as that of During this vacuuming, the heater 13 heats the wafer 4 and bakes the photoresist film 12 on the main surface of the wafer 4 without rotating it.

When baking, that is, vacuum baking, is performed, the vacuum gate 10 is opened. Further, the wafer 4 on the stage 11 is placed by the transfer mechanism 27 on the auxiliary stage 32 at the raised position of the object support mechanism 23 in the processing chamber 16 . Thereafter, this auxiliary stage 32 passes through the through hole 35 of the support stage 33 and descends. During this descent, the wafer 4 placed on the auxiliary stage 32-J2 is transferred onto the accommodation recess 36 of the support stage 33. next,
The cover 34 is attached to the support stage 33 side with the support shaft 39 at the center.
It rotates 0 degrees to cover the peripheral portion of the wafer 4 accommodated in the accommodation recess 36.

Next, the support stage 33 is rotated by 90 degrees to stand upright as shown in FIG. 3, so that the main surface of the wafer 4 faces the exit port 25.

Next, desired ions from among the ions generated by the ion irradiation device 2, that is, the ion source (not shown) are selected by a purchase analysis magnet, focused, and accelerated by an acceleration tube. , Figures 1 and 2
The ion beam becomes an ion beam 24 as shown in the figure and is implanted into the main surface of the wafer 4. This ion implantation (implantation) is performed over several seconds to several minutes.

When the ion implantation into the wafer 4 is completed, the support stage 33 is reversely rotated by 90 degrees about the rotation axis 37, so that the wafer 4 returns to the horizontal position. In addition, the cover 34 that overlapped the support stage 33 to prevent the wafer 4 from falling off is
It rotates in the opposite direction about the support shaft 39 by at least 90 degrees and comes out of the upper area of the accommodation recess 36 . Thereafter, as shown in FIG.
At the same time, the mechanical chuck 30 of the transfer mechanism 27 clamps the auxiliary stage 32 and the wafer 4. This mechanical chuck 3
0 is the wafer 4 on the stage 20 of the unloader preliminary chamber 6.
to be transferred. Prior to this transfer, the evacuation gate 18 of the unloader preliminary chamber 6 is opened.

Next, the wafer 4 is placed on stage 2 of the unloader preliminary chamber 6.
0, the vacuum gate 18 is closed,
Thereafter, the unloader gate 17 is opened. Then, the transport mechanism 22 moves forward and picks up the wafer 4 on the stage 20, and the stage 20 is driven to accommodate the wafer 4 in the cartridge 21 of the unloader 7.

〔effect〕

(1) Prior to ion implantation, the ion implantation apparatus of the present invention performs a vacuum baking process on the wafer in a vacuum baking chamber adjacent to the processing chamber to degas the photoresist film on the main surface of the wafer. When ions are implanted in the processing chamber, gas is no longer released from the photoresist film, so that the effect of preventing 17 staining of the processing atmosphere can be obtained.

(2) According to (1) above, the ion implantation apparatus of the present invention:
Since the harmful effects caused by the ion beam and residual gas are also eliminated, it is possible to achieve the effect that highly accurate ion implantation is possible.

(3) According to (1) above, the ion implantation apparatus of the present invention:
The effect is that it is also possible to process large-diameter wafers.

(4) Due to the above fil and (2), the ion implantation apparatus of the present invention has the effect that the yield can be improved.

(5) According to (1) to (4) above, according to the ion implantation apparatus of the present invention, a synergistic effect of reducing ion implantation cost I- can be achieved by improving productivity with large-diameter wafers. It will be done.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the Examples described in -tx, and it is understood that various changes can be made without departing from the gist of the invention. Needless to say, if, for example, the ion implantation time and the vacuum baking time are significantly different, several vacuum heating stations (vacuum baking stations) may be required in the processing chamber for index matching.
Even if , the same effect as that of the above embodiment can be obtained.

Further, the present invention may be applied to an ion implantation apparatus having a structure in which wafers are arranged at regular intervals around a rotating disk and ions are implanted into a plurality of wafers by rotating the disk. Effects similar to those of the previous embodiment can be obtained.

Moreover, the vacuum baking device (vacuum baking chamber) in the present invention
The same effect as that of the above embodiment can be obtained even if it is arranged in a series of production lines.

[Application field]

In the following explanation, the invention made by the present inventor is mainly applied to the ion implantation technology for wafers, which is the field of application in which the invention is based, but the invention is not limited thereto.

The present invention can be applied at least to processing techniques in which undesired gases and the like are generated due to heat generation during processing.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view showing the conceptual structure of an ion implantation apparatus according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the wafer hook mechanism, and FIG. 3 is also showing the ion implantation part. 4 is a partial plan view showing the wafer chuck state, and FIG. 5 is a flowchart showing the working process. DESCRIPTION OF SYMBOLS 1...Main body, 2...Ion irradiation device, 3...Vacuum baking device, 4...Wafer, 5...Loader, 6...
- Spare room for unloader, 7... Unloader, 8...
Preliminary vacuum evacuation system, 9...0-da gate, 10...
Vacuuming gate, 11... Stage, 12... Photoresist film, 13... Heater, 14... Cartridge, I5... Transport mechanism, 16... Processing chamber, 17...
・Unloader gate, 18... Vacuuming gate, 1
9... Preliminary vacuum evacuation system, 20... Stage, 21.
...Cartridge, 22...Transportation mechanism, 23...Workpiece support mechanism, 24...Ion beam, 25...
Output port, 26... Vacuum exhaust system, 27... Transfer mechanism,
28... Support shaft, 29... Arm, 30... Mechanical chuck, 31... Claw, 32... Auxiliary stage, 33... Support stage, 34... Cover, 35
...Through hole, 36...Accommodating depression, 37...Rotating shaft,
38...Support plate, 39...Spindle, 4th 2nd
Figure 3

Claims (1)

[Claims] 1. An ion implantation apparatus for implanting ions into a workpiece, the apparatus being equipped with a vacuum baking device for baking the workpiece in a vacuum atmosphere before ion implantation. .