JPS62105347A - Semiconductor manufacturing apparatus - Google Patents

Abstract

PURPOSE:To prevent breakdown of a wafer due to leaping by separating the wafer from a seat while holding it by means of a fastening ring and a pushup pin, and thereafter separating the wafer from the fastening ring. CONSTITUTION:A wafer 1 is pushed against a cooling wall 2 by means of a fastening ring 3 and irradiated with a beam 4 under vacuum environment. A pushup pin 10 is pushed by a spring 12 against the fastening ring 3 so as to hold the wafer 1 between the pin 10 and the ring 3. If a piston 11 is lift when the wafer 1 is replaced after irradiation process, the fastening ring and the pushup pin 10 are lifted simultaneously for separating the wafer 1 held between them from a seat 5. Even when the wafer 1 is in tight contact with the seat 5, it 1 is pushed up silently while being held between the fastening ring 3 and the pushup pin 10. Consequently, the wafer is separated silently without leaping from the seat 5, resulting in prevention of breakdown.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a wafer cooling unit structure when a semiconductor wafer is heated in a vacuum, such as in an ion implantation device or a sputtering device.

[Background of the invention]

In a device that processes semiconductor wafers in a vacuum, such as an ion implantation device, ions collide with the wafer, converting kinetic energy into thermal energy and generating heat on the wafer surface. The surface of the wafer is often coated with a resist layer for phosphorography processing, and there is a permissible limit to the temperature rise of the wafer due to the thermal properties of the resist. Therefore, it is necessary to quickly remove the heat generated by the wafer.
Since wafer processing is performed in a high vacuum, heat removal by radiation to the surrounding area or convection from the ion implantation surface cannot be expected, and it is necessary to cool the wafer from the back surface.

As described in Japanese Patent Application Laid-Open No. 58-213441, the conventional apparatus has a structure in which the wafer is clamped against the cooling wall by a ring, and the wafer is cooled from the back surface by a conductor. In such an apparatus, in order to transfer all of the large amount of heat applied to the wafer from the back surface of the wafer to the cooling wall, it is necessary to keep the contact thermal resistance between the wafer and the cooling wall small. However, since the wafer is placed in a high vacuum, if there is even a slight gap between the wafer and the cooling wall, the wafer will locally become overheated because the gap is almost adiabatic.

In order to improve contact over the entire surface of the wafer, it is necessary to shape the cooling wall surface as in the above-mentioned Japanese Patent Application, or to insert a thermally conductive flexible sheet between them. Even if the shape of the cooling surface is ideal, if the wafer surface is rough, warped, etc., a small gap will occur, so it is practical to sandwich a thin thermally conductive sheet between them.

The contact thermal resistance can be reduced by sandwiching a thermally conductive sheet and attaching the wafer to the sheet using a tightening ring.
When removing the wafer after processing, the wafer sheet remains in close contact with the wafer, and when the wafer is pushed up with a push-up pin, the wafer may be thrown up and damaged.

It may be possible to process the back side of the sheet to make it easier to peel off, but if the adhesion deteriorates, the contact thermal resistance will increase.

It is necessary to improve adhesion and make it easy to peel off when removing the wafer.

FIG. 3 shows an example of a conventional structure.A wafer 1 is irradiated with a beam 4 in a vacuum atmosphere and generates heat. Wafer temperature 10
In order to suppress the temperature to about 0'C, a ring 3 is used to tighten the cooling wall 2. A thermally conductive sheet 5 is sandwiched between the wafer 1 and the cooling wall 2 to reduce the contact thermal resistance. The cooling wall 2 is cooled by water or the like. For tightening, the ring 3 is attached to a support plate 8 via a rod 7, and a spring 9 presses the wafer 1 against the wall surface. After the wafer is subjected to beam irradiation processing in this state, the wafer is replaced. To replace the wafer, first the push-up piston 11 rises and pushes up the support plate 8. Tightening with support plate 8 is a ring, push-up pin], 04'v rises. Push up pin 1
FIG. 4 shows the state when 0 has risen to the wafer position.

The figure shows the case where the wafer is in close contact with the sheet.

When the piston 11 further rises (Fig. 5), the pin 10
When the wafer 1 is separated from the push-up sheet 5 and lifted to a certain height, the wafer is transferred by a transfer device (not shown). If the wafer 1 is in close contact with the sheet in the state shown in FIG. 4, when it is pushed up by the pins 10, the wafer will often spring up and hit the ring during tightening, causing damage.

[Purpose of the invention]

An object of the present invention is to provide a structure that secures wafer cooling performance using a thermally conductive sheet that has good adhesion to the wafer, and prevents damage due to the wafer being lifted up when the wafer is removed.

[Summary of the invention]

In the present invention, when pushing up the tightening ring, the wafer periphery is initially pushed up slowly while being fixed to the ring, and the ring is released to ensure that it is separated from the sheet, especially when tightened, and then the wafer transfer device is used to The present invention is characterized in that when the wafer is transferred, the wafer is prevented from flying up even if the wafer and the sheet are in close contact with each other.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIG.

The wafer 1 is pressed against a cooling wall 2 by a ring 3, and is irradiated with a beam 4 in a vacuum atmosphere.

The difference from the conventional structure is that the push-up pin is pressed against the ring 3 by a spring 12, and the wafer 1 is held between the pin 10 and the ring 3.

When replacing the wafer 1 after irradiation processing, the push-up piston 11
When the support plate 8 rises, the tightening ring and the push-up pin 10 rise simultaneously, and the wafer 1 held by both is also pulled away from the sheet 56, until the wafer reaches a certain height as shown in FIG. -1- When raised, the push-up pin 10 is prevented from rising, and from then on, only the ring 3 is tightened. Thereafter, wafers are exchanged by a transfer device (not shown). .

Even if the wafer 1 is in close contact with the sheet 5, the tightening is done by the ring 3.
By gently pushing up the wafer while being held between the push-up pins 10 and 10, the wafer is gently pulled away from the sheet 5 without flying up.

The surface of the periphery of the sheet 5 may be roughened to make it easier for the wafer to separate from the sheet 5 when it first moves upward. It is also effective to prevent the PR9 force from being applied to the wafer by particularly slowing down the push-up speed at first. The lower end of the spring 12 does not necessarily need to be pushed up by a support plate, and a seat may be provided on the lower surface of the cooling wall.

〔Effect of the invention〕

In the case of beam irradiation, it is advantageous from the standpoint of cooling that the wafer and the sheet have high adhesion, and it is necessary that the wafer be easily separated from the sheet when replacing the wafer. According to the present invention, even if the wafer and the sheet are in close contact with each other, the wafer will not fly up and be damaged during wafer exchange.

In addition, since it can be used with good adhesion between the wafer and the sheet, processing that generates a large amount of heat is possible.

This has effects such as being able to improve throughput.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 shows the situation during the first wafer exchange. FIG. 3 is a longitudinal sectional view of the conventional structure, and FIGS. 4 and 5 show the situation during wafer exchange. DESCRIPTION OF SYMBOLS 1...Wafer, 2...Cooling wall, 3...Tightening ring, 4...Beam, 5...Thermal conductive sheet, 6...
Cooling channel, 7... Rondo, 8... Support plate, 9...
Spring, 10... Oshiage No. 1 Mikyo Z diagram

Claims (1)

[Claims] A device that removes the heat generated on the wafer from the backside of the wafer when processing semiconductor wafers in a vacuum. A flexible sheet is interposed between the wafer and the cooling wall, and the periphery of the wafer is pressed against the wall using a tightening ring. In the structure, at the initial stage of pushing up the clamping ring, the wafer is pulled away from the sheet while the wafer is held by the clamping ring and the push-up pin, and the clamping ring and wafer are separated after the wafer and the sheet are definitely separated. A semiconductor manufacturing device characterized by: