Avoid costly downtime on your PCB production line with WLCSP compatible pick and place machines from Capital Equipment Exchange. As technology advances, it also becomes smaller and more detailed. Make sure your SMT assembly processes can handle WLCSP components quickly and efficiently. We'll show you how.
WLCSP (wafer level chip scale package) is the technology of packaging silicon semiconductors with integrated circuitry. This type of packaging is often more streamlined than more traditional wafer dicing technologies. There are many reasons WLCSP sees increased use in PCB manufacturing.
Unfortunately, these benefits can be a trade-off in cost for many manufacturers. These tiny packages can cost in lost productivity and additional variance due to rework. That's because WLCSP parts are challenging to place for many SMT machines currently in production.
To correctly place these components, a machine needs to recognize the bumps on the bottom side of the component, make sure the bumps are within spec, and then register and place it.
Many machines in production today will not be able to see features this small and will try to place the component like it was just 0402 or 0603 – ignoring the bumps entirely.
For example, let's take a common gate array component, historically supplied in either a SOT-23-5 package or possibly an 8-Lead MSOP. Most, if not all manufacturers, have the capability in their current processes to handle these older package styles with acceptable quality yields.
This historical picture changes with the introduction of tiny WLSCP parts.
The five bump WLCSP shown has a bump spacing of 500 microns (.5 mm) and a bump diameter of 260 microns (.26 mm). This is all within a body size that essentially matches that of an 0603 chip component.
Compared to a standard SOT-23-5 with a body size closer to that of a 1206 chip and a lead spacing of 950 microns (.95 mm), the potential process challenges with the WLCSP become apparent.
The key to getting all the benefits possible out of WLCSP parts is choosing the right SMT equipment to handle these packages. Screen printing and parts placement machines are crucial in establishing your new processes to manage manufacturing costs and quality yields.
Your screen printers need to have alignment accuracy and repeatability to handle the solder deposits for the small bumps on the WLCSP. On a part that has a 260-micron bump size on 500-micron spacing, for example, even a slight offset can create defects that will require reworks or possibly result in a field failure.
Your pick and place machinery needs to be able to pick and place these tiny WLCSP components accurately. Proper vision magnification, real-time pickup offset adjustment, closed-loop pressure control for both the pick and place cycle (and a capable alignment process that is accurate and repeatable), are all required for optimal results.
WLCSP compatible SMT machines can be tested to verify that they are performing to specification, saving you downtime, frustrations, troubleshooting, and money. These tests are typically done with a CPK analysis.
Here is a CPK analysis from a machine that was recently sold and prepared by CEE for a customer that has a requirement to place this five bump WLCSP:
At Capital Equipment Exchange, we regularly help manufacturers looking to break into WLCSP or streamline their current production lines with used pick and place machines able to handle wafer-level-chip-scale-packages. We not only supply you with equipment we know works, but we can also provide you with proof that our machines can handle your required WLCSP specifications.
Our Universal Genesis GC-30S SMT pick and place machines are a great example.
Find the Genesis GC-30S SMT pick and place machine, and other reliable WLCSP compatible pick and place machines at Capital Equipment Exchange. Our used SMT equipment range includes screen printers, reflow ovens, AOI, wave solder machines, ICT, flying probe test machines, and spare parts.
You can be confident that we understand the processes and demands related to PCB manufacturing and can supply you with the highest quality solutions at affordable, used-equipment prices. Place your order today.