Gold Plating

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Gold Plating
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Gold Plating Station
Equipment Details
Technology Wet bench
Materials Restriction Metals
Material Processed Gold
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)
Equipment Manual
Overview System Overview
Operating Procedure SOP
Supported Processes Supported Processes
Maintenance Maintenance


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.

Announcements

The Online Logbook needs to be filled out every time this tool is used. Doing so allows other users to verify the quality of plating and the plating rate before they come in for processing.

Capabilities

  • Plating rate is characterized monthly (see section below)
  • 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.

System overview

Hardware details

  • BDT-510 makeup (plating solution itself)
  • BDT Brightener (an additive for improving surface finish)
  • Neutronex 309 Liquid Conducting Salt (proprietary formulation)
  • Glass tank
  • Wafer holder
  • Platinum Anode on PTFE (Teflon) holder
  • Hotplate with temperature probe
  • Filter and filter pump
  • Programable current source (DC)
  • Digital Volt Meter

Substrate requirements

  • Small piece parts to 6" wafers (processing 6" wafers requires additional configuration by LNF Staff; please create a Helpdesk ticket for assistance)
  • All substrates

Safety

Proper PPE for this bench are apron, face shield, trionic gloves and safety glasses
Warning 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 (liquid and solid) MUST be collected; the arsenic salts employed in the plating solution are toxic and need to be handled appropriately.
    • Gold plating solution is NOT disposed of down the drain.

Material restrictions

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 info@lnf.umich.edu for any material requests or questions.


Supported processes

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 12XT can be patterned in 5:1 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.


Warning Warning: This page has not been released yet.


Standard operating procedure

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Checkout procedure

  1. Read through this page and the Standard Operating Procedure above.
  2. Train and practice with your mentor or another authorized user until you are comfortable with tool operation.
  3. If your mentor or another group member is not authorized open a help desk ticket requesting training.
  4. 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.

Maintenance

  • The solution is characterized monthly by a tool engineer.
  • If the potential during plating is over 1 V, plating quality is assessed and bath is adjusted.
  • If you find issues during plating (i.e. quality, rate, etc.), please create a helpdesk ticket