Dummy Dies and
Daisy-Chain Test Chips
Silicon test dies that stand in for your product during assembly development: pad arrays at your pitch, daisy chains that close through the mating substrate, UBM and bumps of your choice, and probe pads to read every chain. Diced to size, identified, from one wafer.
reviewed geometries
layout and dicing review
formats
order
Test dies that reveal the joint, not the device
Daisy-chain test structures measure continuity and total resistance through a defined group of assembled joints. Segmented chains help narrow the location of an open circuit; dedicated Kelvin structures can evaluate selected joints when the layout provides separate force and sense access. We fabricate the dies; assembly and electrical test are quoted separately or performed by you.
Schematic section of an assembled pair: die-side and substrate-side links alternate through the bumps, and the chain is read between the two terminals. Kelvin measurement of a selected joint needs separate force and sense routing.
Dummy dies
Mechanical stand-ins with pads, passivation and optional bumps, for pick-and-place, underfill and thermal trials without a live device.
Daisy-chain dies
Die-side links that close through the mating substrate to form the chain, with accessible start and end terminals. Segmentation narrows an open to a region; four-terminal Kelvin structures with separate force and sense routing are designed for selected joints where joint-level data are needed.
Bump and UBM options
Bare pads, UBM only, Cu pillar with SnAg cap, SnAg, AuSn or indium bumps, or Au bumps; solder routes delivered as-plated or reflowed, Au and indium as deposited. See Cu pillar and UBM.
Mating substrates
Matching interposer or substrate coupons with the complementary chain, so the pair closes the loop. See interposers.
Dummy Dies and Daisy-Chain Test Chips
Scope and specification options. Every figure is confirmed for your program in the quotation.
Typical ranges
| Parameter | Typical | Note |
|---|---|---|
| Die size | Custom, from about 1 × 1 mm up to the reticle field; larger by stitching where available | Confirmed after layout review; street width set to your saw or our dicing conditions |
| Pad and bump pitch | Cu pillar from 40 µm on reviewed geometries; solder bumps from about 80 µm; Au, AuSn and indium routes each have their own minimum | Pitch is confirmed per bump route and layout |
| Pad metal | Al or Cu pads with polyimide or SiN passivation | Opening size per pitch |
| Chain layout | Segmented chains, corner and edge chains, Kelvin structures | Probe pads at die edge or on the substrate |
| Bumps | Bare pads; UBM only; Cu pillar + SnAg cap; SnAg, AuSn or indium bumps; Au bumps | Delivery state by material: solder routes as-plated or reflowed, Au and indium as deposited or plated; height and diameter per pitch |
| Thickness | Standard or thinned to 100-200 µm | Thinning on carrier where needed |
| Identification | Die ID marks and wafer map | Traceability per lot |
| Inspection | Optical, bump height and coplanarity as agreed | Chain resistance is measured after assembly, a separate step; a dummy die is passive and is not a powered thermal test chip |
From pitch to diced dies
- 01Define the dieSize, pitch, chain map, bump type, mating part.
- 02LayoutPad array and chain routing; GDS returned for approval.
- 03FabricateMetal, passivation, UBM and bumps per the option chosen.
- 04InspectOptical and bump metrology as agreed; wafer map.
- 05Dice and deliverDies to size in trays or on tape, identified.
For a test die quotation
| Item | What helps |
|---|---|
| Die | Size, thickness, quantity |
| Array | Pitch, bump count, chain netlist and segmentation, which joints need Kelvin access, viewing side and flip-chip mirror convention, test-pad access after assembly |
| Bumps | Type, height, delivery as-plated or reflowed |
| Mating part | Whether you need matching substrates or already have them |
| Schedule | Target date and stage of your assembly program |
Questions engineers ask before ordering
What information is needed to quote a daisy-chain test die?
Die size and thickness, pad or bump pitch, bump count, chain segmentation and any Kelvin sites, bump type and delivery condition, whether you need matching substrates, quantity and date.
Do you also assemble and test the chains?
We fabricate the dies. Assembly and electrical test of the assembled chains are separate steps that can be quoted on request or kept in-house.
Can the dies be delivered without bumps?
Yes. Bare pads, UBM only, or bumped (Cu pillar with SnAg cap, SnAg, Au, AuSn, indium), as-plated or reflowed.
Processes usually combined with this work
Start your project.
Initial response within one business day.
Share your process requirements, substrate, and production volume. A Nanosystems JP Inc. engineer gives an initial response, typically within one business day. A written quotation typically follows within 7-10 business days after we receive the required information and complete any prerequisite NDA.