Difference between revisions of "Gold Plating"
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Revision as of 12:13, 4 March 2021
|Mask Materials||KMPR, SU-8, Positive Resist|
|Sample Size||6" wafer to 1cm pieces|
|Chemicals Used||BDT 510-510 Makeup, BDT Brightener, Sodium Sulfate (Anhydrous)|
|Supported Processes||Supported Processes|
Gold Plating is typically used for depositing thicker layers of gold onto the surface of the sample. The sample has a seed layer of gold or copper, patterned photoresist and the gold is deposited into the exposed area. It is important that you know the amount of exposed area for the calculations required to use the tool.
- Plating rate (based on 2 mA/cm2 open area) 100 nm/min
- Very small features and high aspect ratios may limit plating rate because of depletion of gold ions in the feature
- Aspect ratio is normally limited by photoresist
- Typical plating thickness ranges from 0.1 to 20 µm. If you are plating thicker than 20 µm please contact a tool engineer.
- BDT-510 makeup (plating solution itself)
- BDT Brightener (an additive for improving surface finish)
- Sodium Sulphate (anhydrous) CAS # 7757-82-6
- Glass tank
- Wafter holder
- Platinum Annode on teflon holder
- Hotplate with temperature probe
- Filter and filter pump
- Programmable current source (DC)
- Digital Volt Meter
- small pieces to 6" wafers
- All substrates
|Warning:||You must use the buddy system for all chemical processing. No processing if you are alone in the lab. If the yellow warning lights are on it means that there are 2 or 1 people in the lab.|
Working with chemicals can be very dangerous. Chemicals used at this bench are some of the most hazardous in the lab. To minimize the chance of accident, make sure you always:
- Wear personal protective equipment. Required PPE at this bench is an apron, face shield, and Trionic gloves.
- Know the properties and hazards of chemicals you are working with. If you don’t know, find out by reading about them or asking staff.
- Plan the details of your process. Before you start working, plan what quantities of chemicals and sample carriers you will use. Plan how you will rinse your sample and what you will do with any waste generated. Make sure you know how the controllers work.
- Do not use this bench without proper training.
- Waste from this bench goes into the LNF’s acid waste neutralization system and then to city sewers.
- No gold plating solution can be used or disposed of here.
The Gold Plating is designated as a Metals class tool. Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under normal circumstances. If a material is not listed, please create a helpdesk ticket or email email@example.com for any material requests or questions.
The only process utilized on this tool is DC gold plating. For resists, we have found that
- SPR 220 is not a good plating resist.
- AZ 9260 can be patterned in 8:1 aspect ratios, and negative resists such as KMPR, and SU8 make very good plating molds and can be patterned in very high aspect ratios, however they are very difficult to remove after plating.
Characterization: With a current of 2mA/cm2 this process electroplates gold at a rate of 0.1 microns/min. The BDT-510 solution is a non-cyanide base process, but the additive contains arsenic.
|Warning:||This page has not been released yet.|
Standard operating procedure
This article 's SOP does not follow the LNF Equipment Manual Guidelines.
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- Read through this page and the Standard Operating Procedure above.
- Train and practice with your mentor or another authorized user until you are comfortable with tool operation.
- If your mentor or another group member is not authorized open a help desk ticket requesting training.
- Schedule a checkout session with a tool engineer via the helpdesk ticket system. If this checkout is successful, the engineer will authorize you on the tool.
- Fillout online logbook to help everyone know solution status.
- The solution test coupons are plating ever 10-15 Amp-min to check plating quality and rate.
- If volts are over 1 V during plating, plating quality is assessed and bath is adjusted.
- Brightener is added when the surface of the plated gold becomes rough
- If you find issues with the plating, please create a helpdesk ticket