Tutorial #107
Terence Q. Collier
October 2010
A classic text on product development1 points out the market and profit advantages of faster product development. The company that is first to market has no competitor, establishing what economists refer to as a “transient monopoly.” You are a sole-source supplier until competition catches up with you.
You may charge a premium price, skimming the early-adopter market until competition develops. Alternatively, you may take advantage of learning-curve cost reductions to bring your costs down quickly, discouraging competitive entries. Either strategy can lead to higher profits.
A key point of the book is that your skillful involvement of other companies by purchasing their services, joint venturing, or sub-contracting can shorten development phases, focus attention, and reduce risk. In other words, letting others help you will bring your products to market faster. This approach minimizes total risk by allowing each participant to concentrate on their area of excellence.
In flip chip microelectronics assembly, a key development bottleneck is often the time and effort required to obtain the relatively small quantity of each of a variety of bumped die required for prototyping, pre-production assembly and test. Most bumping houses consider bumping single wafers to be a low priority, high priced activity. Typical lead times can be four or more weeks, a potential major delay.
While your immediate need may be only a few hundred die, you are compelled to purchase bumped wafers with thousands of die for each required type of device, with total costs in the tens of thousands of dollars.
CVInc2 is an external product development source that can help you to save this time and money. We have developed a technique to bump single die with consistency, repeatability and reliability.
Figure 1. Bumped single die. (courtesy CVInc)
Bumping single die saves both time and cost. Often only a few die are enough to meet customer needs or to review the first pass on the silicon.
By bumping a small quantity of die, the cost can held to the low thousands of dollars, compared to the tens of thousands of dollars charged to bump a full wafer.
You can choose from a variety of bumping alloys. You can obtain the same die bumped in both leaded and lead-free versions, for comparative evaluation. Thinned single die can be bumped, as well as partial wafer sections, MEMS and various substrate materials.
Bumping single die also has advantages for multi-project wafers, where the wafer is shared with other development teams. The wafer can produced with standard aluminum bond pads. The flexibility to either wirebond these die or to bump them with a variety of metals can provide real-world application data for comparative evaluations.
Some die cannot be flip-chip assembled as produced because of pad material or layout limitations. In that case, we can provide pad redistribution, allowing flip chip or wafer level packaging.
Figure 2. Redistributed die. (courtesy CVInc)
A flip chip solution with pad pitch and spacing that require redistribution may typically mean waiting six to eight weeks for redistributed samples from other sources. CVInc can supply samples of RDL die, including bumps, within six working days.
Figure 3. Bumped redistributed die. (courtesy CVInc)
Having the die this quickly not only provides customer samples but also furthers our two initial objectives: lower development costs and shorter time to market. Bumping wafers in one week instead of six or eight lowers your costs and raises your profits.
The sooner your customer has samples, the more likely your design win. In many cases first to sample is first to market. Most of all, speedy sampling lets the die be tested in the new product while leaving time for improvements.
References
[1] Milton D. Rosenau, “Faster New Product Development: Getting the right product to market quickly.” AMACOM, New York, NY, 1990. ISBN: 9780814459423
[2] Terence Q. Collier
CVInc.
www.covinc.com