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Browse Prior Art Database

Double Bottom Diffusion Boat

IP.com Disclosure Number: IPCOM000092190D
Original Publication Date: 1968-Oct-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Martel, A: AUTHOR [+2]

Abstract

This diffusion boat minimizes the defect spots on the processed wafers due to the source powder projections. The diffusion boat includes two separate parts. Lower part 1, which is a rectangular box without cover, includes a bottom 2 and walls 3. Part 1 contains the source powder during the diffusion process. Upper part 4 of the diffusion boat, also a rectangular box without a cover, includes bottom 5 and walls 6 and 7. Interposing blocks 8 are fixed under bottom 5, and are a little higher than walls 3. Blocks 8 are located in such a way that they accommodate the inner corners formed by walls 3 when part 4 is lowered and placed over part 1. When parts 1 and 4 are so adjusted, a small space is maintained between the top of walls 3 and bottom 5 in order to allow the doping vapor to flow freely.

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Double Bottom Diffusion Boat

This diffusion boat minimizes the defect spots on the processed wafers due to the source powder projections. The diffusion boat includes two separate parts. Lower part 1, which is a rectangular box without cover, includes a bottom 2 and walls 3. Part 1 contains the source powder during the diffusion process. Upper part 4 of the diffusion boat, also a rectangular box without a cover, includes bottom 5 and walls 6 and 7. Interposing blocks 8 are fixed under bottom 5, and are a little higher than walls 3. Blocks 8 are located in such a way that they accommodate the inner corners formed by walls 3 when part 4 is lowered and placed over part 1. When parts 1 and 4 are so adjusted, a small space is maintained between the top of walls 3 and bottom 5 in order to allow the doping vapor to flow freely. The tops of walls 7 of part 4 are provided with cylindrical slotted members 9. Before proceeding to the diffusion step, the source powder is regularly distributed on bottom 2 of part 1. Next, the wafers to be processed are placed in the slots of members 9 with guard wafers at each end of the row. Then the two parts are put together and placed in the vacuum-sealed capsule for diffusion. This arrangement allows the doping vapor to flow without any projection of source material.

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