HK 300mm Compressed Heater Chuck

 BACKGROUND

To reduce the overall cost for an existing application, BCE developed a 300mm aluminum heater chuck that is un-brazed utilizing the compression of two plates with countersink set screws. The heater surface specs were 0.003” flatness at a 0.005” parallelism. Using a 208-volt power supply at 9.7ohm, start @ 25°C temperature and ramped from 100°C to 465°C in 23 minutes. 

SCOPE

Aluminum Heater Chuck needed to satisfy the following:

• Achieve temperature up to 435°C  @ +/- 2% or better 
• Internal element must be able to withstand temperatures up to 600°C
• Anodized surface for electrical isolation 
• 208 Volt, 9.7 Ohm, 4,460 Watt (+5% / - 10%) 
• Thermocouple bore hole to be placed at the center (variable) 
• 4 point temperature profile on the top surface of the heater 
• Used an infrared sensor for each 4 point locations
• FINISH: Hard coat anodize per MIL-A-8625F, Type 3 Class1 Hard-coat thickness  

OUTCOME

BCE produced a highly effective high 300mm heater with exceptional uniformity better than the proposed 435°C (+/-2%).  After the initial ramp, the heater maintained 435°C (+/- 1%) as per the chart below (Temp profile #5). 

BCE

510-274-1990

https://bcemfg.com

Consistent, Repeatable and Efficient Results from a 300mm Semiconductor Chuck Heater with Mirror Finish

300mm Hot Chuck Heater with Mirror Finish

Semiconductor fabrication involves numerous processes, materials, and specialized equipment. The base semiconductor material from which integrated circuits and microchips are manufactured comes in the form of round, thin crystalline disks referred to as wafers. During semiconductor production, wafer temperature uniformity is one of the most critical factors affecting product quality and consistency.

To increase the speed at which a physical or chemical reaction takes place, heat is applied at various stages of the process. Heat is applied through the use of heated chucks which provide precise thermal uniformity which, as mentioned above, is critical for production.

Click image for larger view.

To summarize, the goal of the heated chuck is to provide a very high level of temperature uniformity across the entire wafer surface so that processing output is highly consistent, repeatable and efficient.

BCE, a manufacturer of custom electric heaters and thermal systems was asked by a customer

to replace a cast aluminum heater plagued with surface finish problems. Poor surface finish equates to poor thermal uniformity and heat transfer. To add insult to injury, the vendor was quoting extremely long lead-times for replacements.

Using their broad experience in semiconductor chuck heater design, BCE knew immediately the best solution would be a vacuum brazed-in 6061 T6 aluminum heater with a 2-3 Ra μin surface.

Specification to be met:

• Temperature uniformity +/- 1%
• 350°C - 450°C Temperature range
• Surface finish of 2-3 Ra μin
• Hard coat Anodize
• 6061 T6 Aluminum
• Be able to heat ceramic top plate
•  20 Meg-ohm isolation at 1000 VDC
• Hi-pot 2E + 1K at 3mA

Results

BCE designed a chuck heater using their own proprietary internal element patterns, notches, and thermocouple holes, as well as adding additional manufacturing processes to provide the 2-3 Ra μin finish. Vacuum integrity for the customer has been greatly increased as well as contact with the ceramic workpiece and temperature uniformity.

For more information, contact BCE by calling 510-274-1990 or through visiting their website at https://bcemfg.com.