Optical Wafer Heater for Cryogenic Processing
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Solution Overview
Problem
Current methods for warming processed semiconductor substrates above the dew point after cryogenic processing are inefficient, leading to prolonged warming times and reduced manufacturing throughput due to unwanted condensation or frost formation.
Innovation Solution
A vacuum assembly comprising a processing chamber, substrate handling robot, and a heater or radiative energy source is used to warm substrates above the dew point within a transfer chamber, allowing for rapid absorption of energy and avoidance of condensation, with the heater emitting energy as the substrate is transferred from the processing chamber to the loadlock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If convection warming with nitrogen gas is used in loadlock chamber, then substrates can be warmed above dew point, but warming time is prolonged to 5-10 minutes reducing manufacturing throughput
Solution Approach 1:
The patent replaces the mechanical convection-based heating system with an optical/electromagnetic radiation-based heating system. Specifically, an infrared heater or laser source emits radiant energy that directly heats the substrate surface, eliminating the need for convective heat transfer through nitrogen gas. This substitution reduces warming time from 5-10 minutes to approximately 10-30 seconds while achieving the same temperature increase above dew point.
Solution Approach 2:
The patent employs periodic or pulsed heating action where the infrared heater or laser is activated only during the critical warming phase when the substrate is in the transfer chamber, rather than continuous convection heating. The heater emits radiant energy in pulses or continuous waves that rapidly raise the substrate temperature during the brief transfer window, optimizing both speed and energy efficiency.
2Productivity
If rapid warming is implemented to increase manufacturing throughput, then warming time is reduced, but risk of condensation and frost formation increases
Solution Approach 1:
The patent applies preliminary action by initiating the radiant heating process immediately as the substrate enters the transfer chamber, before the substrate temperature drops below dew point. The infrared heater or laser is pre-positioned and activated synchronously with substrate arrival, ensuring temperature maintenance throughout the transfer process. This preemptive heating strategy prevents condensation formation while enabling rapid throughput.
Solution Approach 2:
The patent introduces an intermediary radiant heating system (infrared heater or laser source) that acts as a mediator between the cold substrate and the thermal environment. This intermediary device provides direct radiant energy transfer to the substrate surface, creating a controlled thermal field that prevents moisture condensation while enabling rapid warming. The intermediary heater serves as a buffer that decouples the substrate temperature control from the ambient chamber conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution significantly reduces warming time to approximately 5-20 seconds, preventing condensation and frost, thereby enhancing manufacturing throughput by eliminating the need for prolonged convection warming and allowing for immediate transfer of processed wafers.
Implementation Method 1
a heater or other radiative energy source... the heater emits energy on at least one of the one or more substrates
Implementation Method 2
the heater emits energy on at least one of the one or more substrates when the substrate handling robot displaces at least one substrate in the transfer chamber
Data Source
AI summary
A vacuum assembly used for warming processed substrates above the dew point to prevent unwanted moisture on the processed substrate surfaces as well as reducing negative impact on manufacturing throughput. The vacuum assembly includes a processing chamber, a substrate handling robot, and a heater which may be an optical heater. The processing chamber is configured to cryogenically process one or more substrates. The transfer chamber is connected to the processing chamber and houses the substrate handling robot. The substrate handling robot is configured to displace one or more substrates from the processing chamber to the transfer chamber. The heater is connected to the transfer chamber above the substrate handling robot such that the heater emits energy incident on the substrate when the substrate handling robot displaces the substrate in the transfer chamber.