Apparatus and method for controlling workpiece temperature

Abstract

An atmospheric controlled chamber includes a support assembly capable of holding a workpiece over a specific surface of the support assembly, a heat-transfer assembly located close to the support assembly and capable of transferring heat to and from the exterior of the chamber, and at least one thermopile device disposed in the support assembly. The thermopile device(s) is configured to transfer heat between the specific surface (or viewed as the held workpiece) and the heat-transfer assembly. A gas assembly is optionally surrounded by the chamber wall and capable of ensuring the existence and controlling the pressure of an essentially static gas between the held workpiece and the specific surface, wherein the gas is used as a thermal medium for conducting heat. The thermopile device acts as an efficient heat pump, so as to provide extra lower / higher workpiece temperature, a greater cooling / heating rates, and more flexible rate control.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention generally relates to heating and cooling a workpiece in an atmospheric controlled chamber and, more particularly, to the application of a thermopile device in an atmospheric controlled chamber for achieving one or more of lower / higher workpiece temperatures, greater cooling / heating rates, and greater flexibility in the control of cooling / heating rates.[0003]2. Description of Related Art[0004]Generally speaking, a workpiece (e.g., a semiconductor wafer, a glass plate, or other plate-like object) can be processed to fabricate different devices, such as an integrated circuit, a memory, a liquid crystal display (LCD), a solar cell, and so on. Different processes sometimes require different processing environments. As room temperature and an atmospheric environment typically surround machines used for processing the workpiece, the workpiece is sometimes treated (e.g., cooled or heated) in an atmospheric...

AI Technical Summary

Benefits of technology

[0013]In view of the foregoing, the present invention provides an atmospheric controlled chamber capable of controlling workpiece temperature and a method of controlling workpiece temperature in an atmospheric controlled chamber. The atmospheric controlled chamber may be evacuated, at a partial pressure, at atmospheric pressure, or in transition. The atmospheric controlled chamber may be a load lock chamber, a process chamber, or a separate chamber dedicated to bringing the workpiece to a desired temperature. In comparison with current practices, the invention may function to reduce heating and cooling times, achieve a greater workpiece temperature range, achieve a more precise final workpiece temperature, and / or adjust the workpiece to different temperatures more quickly.

Problems solved by technology

First, in some cases, the materials allowed in the atmospheric controlled chamber may be restricted, thereby limiting the temperature that the workpiece can achieve. For instance, though popularly used in the semiconductor industry because of its relatively benign characteristics with respect to the device being created, aluminum has a service temperature sometimes below that designed for some processes, resulting in those processes not being properly operated when hardware being used is made of aluminum. Moreover, while static pedestal may present little problems, the dynamic pedestal capable of translating the workpiece in any direction, rotating the workpiece about any axis and / or tilting the workpiece about any axis during a period of processing the workpiece may experience appreciable design difficulties at temperatures below −60° C. and at elevated temperatures. As usual, at least a portion of the dynamic pedestal is made of elastomers to provide the required freedom of translation / rotation / tilting. However, the lower temperature affects elastomers in such a way as to make them brittle and unusable for sealing or structural purpose. Therefore, in chamber environments employing a dynamic pedestal and low workpiece temperature, the design of appropriate seals and mechanisms becomes very difficult if not impossible. The same problem occurs when the workpiece temperature is higher, because the quality of the material, such as metal and elastomer, is degraded under the higher temperature too.

One more disadvantage is the smaller (or limited) cooling / heating rates on the workpiece.

To avoid the degradation of the material, such as the elastomer, the available temperature range of a pedestal is limited.

Therefore, when the workpiece is just moved from the atmospheric environment into the machine, the temperature differential between the pedestal and the workpiece is limited or finite, and then the cooling / heating rates of the workpiece is smaller (e.g., not fast enough for improving the throughput).

A consequential disadvantage is the smaller flexibility and precision on the adjustment of the workpiece temperature.

However, for many commercial chillers, the servo control of temperature can be affected but the time required to adjust temperature may be long and imprecise.

Hence, the workpiece temperature may be not precisely controlled or even not flexibly adjusted to meet the different requirements of differential processes.

Images