Semiconductor Fluxes
Wafer Bumping Flux
Indium Corporation creates and provides top-tier wafer bumping (bump fusion) fluxes designed to eliminate oxides and other contaminants during reflow and cleaning. Our fluxes can be applied to solder-bumped and copper-pillar/solder-capped wafers through dispensing or spin coating techniques.
Powered by Indium Corporation
- Water-Washable or Solvent-Cleanable
- Suitable for Use with Various Alloys
- Widely Compatible
Product Overview
Indium Corporation boasts a longstanding reputation for delivering high-quality wafer-bumping fluxes. Our extensive portfolio features materials tailored for various applications, including traditional wafer bumping processes where fluxes are spin-coated onto plated bumps or copper pillars. Additionally, our products excel in printing applications, where flux is applied to wafers before a ball drop process, commonly used in wafer-level CSP (WLCSP), as well as wafer-level and panel-level fan-out packages.
Our wafer-bumping flux products are compatible with polymers and passivation materials commonly used in wafer processing and packaging assembly.
- Applied by jetting or dispense, followed by spin coating to optimize film thickness
- Reflow in inert atmosphere (typically <20ppm O2 level)
- Converts rough, non-spherical, plated, or wafer probe-dented solder bumps into shiny oxide-free bumps
- Proven applications include copper-pillar microbumps and standard solder bumps
- Applied by printing onto wafer or panel using screen or stencil, followed by a ball drop process
- Wafer bumping flux WS-3401 is used in most advanced 2.5D chip on wafer packaging technology.
- Wafer bumping flux SC-5R has been used for over 10 years in legacy products.
Wafer Bumping Flux Products
Wafer bumping with flux continues to be a widely used method, although some have transitioned to flux-less equipment and processes. Flux is highly effective in producing uniformly low-oxide and well-rounded bumps with optimal morphology.
| Flux Type* | Flux Application Method | Description | Cleaning Method | Halogen-Free | Material |
|---|---|---|---|---|---|
| SC | Dispence/Spin Coating | High-Pb, SnPb-eutectic, and SnAg solder bumps | Solvent- or aqueous-based chemistry | Yes | SC-5R |
| WS | Dispence/Spin Coating | 20-65 micron pitch copper-pillars with SnAg or Sn100 microbumps | Warm DI water | Yes | WS-3401 WS-3543 |
| Flux Type* | Flux Application Method | Description | Cleaning Method | Halogen-Free | Material |
|---|---|---|---|---|---|
| WS | Printing | 0.5mm and smaller pitch wafer-level or panel-level package; also suitable for LED die-attach application | Warm DI water | Yes | WS-676 WS-759 WS-829 |
| Considerations | Solder Paste Printing | Plating | Flux/Solder Ball Printing | C4-NP (Suess/IBM) |
|---|---|---|---|---|
| Used In High Volume Manufacturing? | Yes | Yes | Yes | Yes |
| Alloy Restrictions | All solder alloys, as long as powder can be made | Binary alloys only (Sn/Pb, Sn/Ag, Sn/Cu etc.) due to alloy control issues | All solder alloys, as long as sphere can be made | Probably limited to binary alloys |
| Bump Size | Down to around 125micron pitch only. Only 45% of paste volume is metal | Down to 2micron bumps feasible: possibly less | 60micron bump diameter in mass production, but most commonly used for wafer level CSP manufacturing | Unknown |
| Bump Uniformity | OK: can vary significantly with age of solder paste and print process variables | Good | Good with appropriate tight tolerance solderspheres | Good |
| Voiding | Common | Little or no with a controlled plating process | Little or no | Little or no |
| Cost Comparison | Low Cost | More Expensive | Low Cost | High Capital Cost |
| Prototyping | Fairly Easy | Complex | Easy | Complex |
Product Data Sheets
WS-3518 Wafer Flux PDS 98431 (A4) R3.pdf
WS-3518 Wafer Flux PDS 98431 R3.pdf
WS-3543 Wafer Flux PDS 98398 (A4) R3.pdf
WS-3401-A Wafer Flux PDS 98764 R4.pdf
Related Applications
Semiconductor Packaging & Assembly
Critical semiconductor packaging ensures functionality and
2.5D & 3D Packaging
Techniques to incorporate multiple dies in a single
Flip-Chip
A crucial technique in advanced semiconductor
Related Markets
Related Products
Semiconductor Fluxes
Extensive portfolio of proven and new semiconductor
Ball-Attach Flux
High-quality water-wash and no-clean ball-attach
Flip-Chip Flux
Offers advanced fluxes for flip chip assembly, water-soluble &
Expert Support for Reliable Results
Do you have technical questions or sales inquiries? Our dedicated team is here to help. “From One Engineer to Another®” isn’t just our motto—it’s our commitment to delivering exceptional service. We’re ready when you are. Let’s connect!
Interconnect Reliability: From the Chip to the System
Interconnect reliability is critical to the reliability of semiconductor packaging and electronic systems. If we look at the life cycle from the chip to the system—from IC design, wafer fab,
Minimizing Graping
Folks, This post is an excerpt on graping, fromIndium Corporation'sThe Printed Circuits Assemblers Guide to Solder Defects. Introduction The growth of personal electronic devices continues to
Semiconductor Fluxes: Part 1
A lot of people who arenot familiar with semiconductor products find themintimidating. I was one of those who found them daunting, but now I realize that semiconductor fluxes should not be
Driving the Packaging Frontier: Part 1
Indium Corporation’s Dr. Andy Mackie, Senior Product Manager, Semiconductor and Advanced Assembly Materials, and Sze Pei Lim, Regional Manager, Semiconductor, discuss how different reliability
Test Methods for ECM Assessment & Process Control: Test Methodologies & Process Control
Phil Zarrow: Brook, we talk about choosing a flux. We start off with these classifications. What is the meaning of it? BrookSandy-Smith: They can mean a lot of different things to a lot of different
In Electronics Manufacturing, Does Cpk =1 Yield 66,800 defects per million?
Folks, As Patty was walking past the Professor’s office on her way to see Pete and Rob, she decided to drop in. “Professor, I got the strangest phone call … a man claimed he had
Reflow of Copper Pillar Microbumps
Wafer bumping processes have evolved in the last 10 years. The semiconductor assembly industry has gone from bumping processes using solder paste printing (with all its concerns of voiding,
Wafer and Substrate Bumping with Solder Paste (I)
This week’s topic is both wafer bumping and substrate bumping with solder paste, and the issue of powder
WS3622 Water Soluble Flux
It’s no secret that I love WS3622. The water soluble flux is a magic bullet for all types of semiconductor packaging applications. As a tech guy, you need to be able to trust a flux – I
Looking for Safety Data Sheets?
Access everything you need — from technical specifications to application guidance — in one convenient location.
Your Success
is Our Goal
Optimize your processes with the latest materials, technology, and expert application support. It all starts by connecting with our team.