GB2082388A

GB2082388A - Improvements in or relating to carrier racks for disc-like objects

Info

Publication number: GB2082388A
Application number: GB8124972A
Authority: GB
Original assignee: Heraeus Quarzschmelze GmbH; Heraeus Schott Quarzschmelze GmbH
Current assignee: Heraeus Quarzschmelze GmbH; Heraeus Schott Quarzschmelze GmbH
Priority date: 1980-08-16
Filing date: 1981-08-14
Publication date: 1982-03-03
Also published as: FR2488731A1; JPS6141128B2; DE8021868U1; JPS5737826A; FR2488731B3; GB2082388B

Abstract

A carrier rack for holding disc- like objects, e.g. semiconductor discs, wafers or slices which rack consists of two pairs of slotted transparent fused silica rods 1 and 2 which are secured to transparent fused silica tubes 3 between each pair of rods at their end area. The upper rods 1 have bores 5 at their end areas to provide index marks on transfer of discs between the silica rack and a plastics carrier rack. The rods may have slots of a greater width at periodically recurring spaces (eg for dopant sources) as well as the slots previously referred to. An additional transverse support tube may be provided between the ends of the rack. <IMAGE>

Description

SPECIFICATION Improvements in or relating to carrier racks for disc-like objects The present invention relates to carrier racks of transparent fused silica to hold a plurality of disc-like objects, the edge areas of which objects extend into slots in elements of the rack, said elements comprising two pairs of rods each provided with slots and extending parallel to each other, the space between one pair of rods being greater than the space between the other pair of rods, both pairs of rods being held immovably in the area of their ends. In use the rack is positioned so that rods are substantially horizontal, the widerspaced rods being above the closer-spaced rods. Hereinafter such racks will be referred to as "of the kind described".

Carrier racks of the kind described are disclosed in British Patent Specification No. GB PS 1 426 503, and have proven very efficient in use. Generally speaking they find application in the semi-conductor industry for processing and holding semiconductor wafers or slices.

It is an object of the present invention to provide a carrier rack of the kind described which is simple to make and economical in use of the expensive transparent fused silica involved and so that the racks loaded with semiconductor wafers or slices can easily be manipulated, and enables them to be easily loaded or reloaded with semiconductor wafers from the usual storage racks of ordinary plastics materials.

It is another object that the use of such racks shall be extended.

Accordingly, the invention consists in a carrier rack of the kind described wherein a transparent fused silica tube is secured at or adjacent each end area of the rods and transversely between the wider and closer-spaced pairs of rods. Advantageously the tubes are welded to the rods.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings which show certain embodiments thereof by way of example and in which: Figure 1 shows an elevation of a first embodiment, Figure 2 shows an elevation of a second embodiment, and Figure 3 shows an elevation of a slotted rod.

Referring now to the drawings, Fig. 1 shows a carrier rack which comprises six parts viz. a pair of upper rods 1, a pair of lower rods 2, and two transverse rods 3 arranged between the pair of rods 1, 2, and adjacent the end areas thereof. All the rods and tubes are of transparent fused silica and the tubes are each welded to the upper and lower rods at points 4. The rods 1 and 2 are slotted at 7, the slots all being of the same width and into which can be engaged the end areas of semi conductor wafers or slices with which the carrier rack is to be loaded in one example of use. As can be seen from Fig. 1, the ends of the transparent fused silica tubes 3 are down wardly chamfered.The transparent fused silica tubes 3 which are arranged transversely to the rods 1, 2 are arranged to receive the tines 6 of a forked handle with which the loaded or unloaded carrier racks can be held and moved. The ends of the upper rods 1 are also pierced with bores 5 which serve as indexing marks on transferring the semi-conductor discs from a plastics carrier rack for example to a carrier rack and vice versa.

The embodiment shown in Fig. 2 differs from that shown in Fig. 1 in that the upper and lower pairs of rods 1, and 2 have an unslotted area 8 each at a given distance from the rod ends and each of these areas is welded to an additional securing tube 9 of transparent fused silica which is mounted transversely to and between the pairs of rods 1 and 2. This reinforcing tube enables double carrier racks or multiple-length carrier racks to be made compared with what might be the normal length of a rack as shown in Fig. 1 and each "normal" length of such a multiple rack can be separated from its neighbour by a pre-determined distance by such additional tube.

Instead of the rods 1 and 2 with slots of the same width as used in Figs. 1 and 2, two rods 10 can be used as shown in the embodi ment according to Fig. 3, having slots 7 of the same width and slots 11 of greater width.

The slots 11 and be located at periodically recurrent spacings 12 in the rod 10 to serve for the reception of plate-like or differently shaped dopant wafers or slices, the slots 7 still serving to receive semiconductor discs.

Carrier racks with rods 10 formed in this way are used for carrying out a doping process with the help of solid sources whereas carrier racks with rods 1 and 2 according to Figs. 1 and 2 are used for other methods of process ing for semi-conductor discs such as the oxi dation and tempering processes as well as doping from the gas phase.

Claims

1. A carrier rack of the kind described, wherein a transparent fused silica tube is secured at or adjacent each end area of the rods and transversely thereto between the wider and closer-spaced pairs of rods.

2. A carrier rack as claimed in claim 1, wherein all said rods have an unslotted area at a given distance from the ends of the rod, and said area being secured to an additional secur ing tube which is arranged transversely to and between the pairs of rods.

3. A carrier rack as claimed in claim 1 or 2, wherein the ends of the tubes interconnecting the pairs of rods are downwardly chamfered.

4. A carrier rack as claimed in claim 1, 2 or 3, wherein each rod of the pair is pierced with a bore adjacent their end areas.

5. A carrier rack as claimed in any of the preceding claims, wherein all said rods have some slots of greater width than the remaining slots at periodically recurrent intervals.

6. A carrier rack as claimed in any of the preceding claims, wherein the rods and tubes are welded together.

7. A carrier rack substantially as hereinbefore described with reference to Fig. 1 of the accompanying drawings.

8. A carrier rack substantially as hereinbefore described with reference to Fig. 2 of the accompanying drawings.

9. A carrier rack substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.