Browse Prior Art Database

INDIVIDUAL LOT LOAD FURNACE FOR EFFICIENT SEMICONDUCTOR PRODUCTION

IP.com Disclosure Number: IPCOM000004709D
Original Publication Date: 2001-Apr-16
Included in the Prior Art Database: 2001-Apr-16
Document File: 2 page(s) / 7K

Publishing Venue

Motorola

Related People

Tim Stanley: AUTHOR [+3]

Abstract

INDIVIDUAL LOT LOAD FURNACE FOR EFFICIENT SEMICONDUCTOR PRODUCTION

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INDIVIDUAL LOT LOAD FURNACE FOR EFFICIENT SEMICONDUCTOR PRODUCTION

by Tim Stanley, Terry Breeden and Mike Tucker

PROBLEM SUMMARY

Furnace steps drive the extended cycle time in Semiconductor Fabs. The extended processing time for each batch furnace step is more than doubled because of time to build and disassemble production batches. Because of this furnace production batch requirement, furnaces can not be integrated directly with lot based tools.

An individual lot load furnace would allow wafers to start processing as soon as they arrive at the furnace, also reducing problems with maintaining the optimal surface state on wafers just before processing since wafers would not have to wait after being prepared in clean stations.

This cycle time and factory integration advantage would result in an improved cost structure that could offset for an increased Cost Of Ownership (COO) that may result from smaller loads per furnace tube. Also the risk of catastrophic failure to four to six lots is eliminated.

PROPOSED SOLUTION

An ultra clean, controlled atmosphere, high temperature processing system like a furnace processor but that can start lots individually rather than waiting to build large batches could solve this problem.

The effective result is to cut the time required in diffusion in half since the time to build and disassemble batches is roughly equal to the processing time in the batch. Also the lot based interface to the rest of the factory is easier to accomplish and automate since batch assembly and disassembly is not required.

As illustrated in FIG. 1, one embodiment of this idea is a furnace that consists of several quartz tubes which are sized for one lot (or possible two lots) but grouped together with common load ports, robotics and controllers. Since batches do not need to be built, large buffers would not be required

Each tube would have it's own heating coils and gas sources, but because of the proximity of the tubes controls, robotics, load ports and other overhead items could be shared. While the same process may be accomplished in each tube, that would not be required. Certainly the processing in each tube will be time shifted since each lot starts processing as soon as it arrives.

Because the systems are short (Only high enough for one lot) two systems could potentially be placed above one and other for conservation of clean room space.

As illustrated in FIG. 2, another option for this embodiment would be a single small tube with dual load ports. This could produce a small simple system.

As illustrated in FIG. 3, another embodiment of this concept is a furnace that consists of several quartz tubes which are sized for one lot but grouped in an array so that heating can be efficiently accomplished and robotics and controllers can be shared.

As illustrated in FIG. 4, an alternate embodiment, the quartz tube is wide enough to permit individual lots to be loaded separately in the tube and removed. While the total time would be the same, individual lots...