Batch furnace assembly and method of operating a batch furnace assembly

Patent metadata

Field	Value
Publication number	US-11971217-B2
Application number	US-202217844911-A
Country	US
Kind code	B2
Filing date	Jun 21, 2022
Priority date	Jun 24, 2021
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

Batch furnace assembly for processing wafers, comprising a process chamber housing defining a process chamber and having a process chamber opening, a wafer boat housing defining a water boat chamber, a door assembly, a differential pressure sensor, and a controller. The door assembly has a closed position in which it closes off the process chamber opening. The door assembly defines in a closed position a door assembly chamber having a purge gas inlet for supplying purge gas to the door assembly chamber for gas sealingly separating the process chamber from the wafer boat chamber. The differential pressure sensor assembly fluidly connects to the door assembly chamber and is configured to determine a pressure difference between a pressure in the door assembly chamber and a reference pressure in a reference pressure chamber. The controller is configured to establish whether the pressure difference is in a desired pressure range.

First claim

The invention claimed is:

1. A batch furnace assembly for processing wafers, comprising:
a process chamber housing defining a process chamber with a process gas inlet and an exhaust wherein the process chamber housing has a process chamber opening;
a wafer boat housing defining a wafer boat chamber, wherein the process chamber opening connects the process chamber with the wafer boat chamber for transferring wafer boats between the wafer boat chamber and the process chamber;
a door assembly having a closed position in which the door assembly closes off the process chamber opening, wherein the door assembly defines in the closed position a door assembly chamber having a purge gas inlet for supplying purge gas to the door assembly chamber for gas sealingly separating the process chamber from the wafer boat chamber;
a differential pressure sensor assembly fluidly connected to the door assembly chamber and a reference pressure chamber within the wafer boat housing and configured to determine a pressure difference between a pressure in the door assembly chamber and a reference pressure in the reference pressure chamber, the differential pressure assembly comprising a pressure sensor within the door assembly chamber and a pressure sensor within the reference pressure chamber; and
a controller configured to compare the pressure difference with a desired pressure difference based on a pressure difference between the process chamber and the reference pressure chamber to establish whether the pressure difference is in a desired pressure range to confirm that the door assembly effectively closes off the process chamber opening.

2. The batch furnace assembly according to claim 1 , wherein the reference pressure chamber is the wafer boat chamber and the reference pressure is a pressure in the wafer boat chamber.

3. The batch furnace assembly according to claim 1 , wherein the batch furnace assembly is configured to determine a pressure within the process chamber.

4. The batch furnace assembly according to claim 1 , wherein the process chamber housing comprises a quartz tube and a metal flange which supports the quartz tube;
wherein the door assembly comprises:
a first door plate including a first seal which engages in the closed position the metal flange of the process chamber housing;
a second door plate including a second seal which engages in the closed position the quartz tube of the process chamber housing;
a third door plate which is rotatably mounted relative to the first and the second door plates; and
a diffusion barrier between the second door plate and the rotatable third door plate, and

wherein the door assembly chamber in the closed position of the door assembly is bounded by the first seal and the diffusion barrier, wherein, in use, purge gas supplied via the purge gas inlet flows via the diffusion barrier to the exhaust.

5. The batch furnace assembly according to claim 4 , wherein the door assembly chamber comprises a flow restriction, and wherein, in use, the flow of purge gas from the purge gas inlet to the diffusion barrier flows through the flow restriction in the door assembly chamber.

6. The batch furnace assembly according claim 5 , comprising a quartz ring between the first door plate and the second door plate, wherein the flow restriction is at least one orifice in the quartz ring.

7. The batch furnace assembly according to claim 4 , wherein the rotatable third door plate is configured to support a wafer boat.

8. The batch furnace assembly according to claim 4 , wherein the diffusion barrier comprises a ring-shaped protrusion on the second door plate having a top which is positioned close to a bottom surface of the third door plate.

9. The batch furnace assembly according to claim 1 , wherein, in use, the purge gas supplied via the purge gas inlet is supplied with a substantially fixed volume flow rate.

10. The batch furnace assembly according to claim 1 , wherein the exhaust is situated at a side of the process chamber housing near the process chamber opening, wherein the process gas inlet is situated at an opposite end of the process chamber housing, and wherein, in use, a process gas flows from the process gas inlet through the process chamber to the exhaust.

11. The batch furnace assembly according to claim 1 , wherein the batch furnace assembly is a vertical batch furnace assembly, wherein the wafer boat chamber is situated below the process chamber.

12. The batch furnace according to claim 1 , wherein the controller refrains from supplying process gas to the process chamber when the pressure difference is not in the desired pressure range.

13. The batch furnace assembly according to claim 12 , wherein the controller generates a warning signal if the pressure difference does not reach the desired pressure range.

Assignees

• Asm Ip Holding Bv

Inventors

• Oosterlaken Theodorus G M
• Jdira Lucian
• Terhorst Herbert

Classifications

• H10P72/0431 Primary

  Apparatus for thermal treatment · CPC title

• H10P72/3312

  Vertical transfer of a batch of workpieces · CPC title

• H10P72/0604

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P72/0441

  Apparatus for sealing, encapsulating, glassing, decapsulating or the like · CPC title

• H10P72/0402

  Apparatus for fluid treatment (H10P72/0441, H10P72/0448 take precedence) · CPC title