AI chip testing takes longer: Why does JPMorgan prefer test sockets to probe cards?

Why do AI chips need more test interfaces?

Probe cards are used for wafer testing before packaging, while sockets are used for final testing and system-level testing (SLT) after packaging. Chiplet technology puts multiple chiplets in a single package. Although probing time for an individual chiplet may decline, JPMorgan expects the combined probing time for all chiplets in each chip generation to increase by 10%–15%.
SLT checks for coordination problems between chiplets under conditions close to actual workloads. The longer the test, the lower the throughput at each socket position, so customers need more parallel test positions to maintain output; more pins also increase the product value per position.
According to the bank’s estimates, from 2026 to 2028, the high-performance computing probe card market will grow from 1.6 billion dollars to 5.9 billion dollars, while the final-test and SLT socket market will grow from 900 million dollars to 3.7 billion dollars. Within the latter, SLT sockets will grow from approximately 700 million dollars to 3.1 billion dollars, accounting for the main increase.

Probe cards have higher technical barriers and profit margins, but fewer suppliers are qualified for high-end sockets, and shares in customer projects are more likely to persist. Local engineering support, timely delivery and early joint development help suppliers qualify and retain subsequent orders.
The bank estimates that WinWay holds more than 70% of Nvidia’s final-test socket market and will enter its SLT socket business in 2026; because testing takes longer, the product value of SLT is 7–8 times that of final testing. The bank expects Nvidia SLT socket revenue to rise from 23% of WinWay’s total revenue in 2026 to 44% in 2028.
Maintaining share depends on service and product quality. On earnings, JPMorgan’s 2028 revenue forecast for WinWay is 7% above market consensus, but capacity expansion costs depress gross margin, leaving its earnings-per-share forecast roughly in line with consensus.

JPMorgan expects MPI’s MEMS probe card capacity in 2027 to exceed 4 times its 2025 level, and MEMS to rise from 20% of total revenue in 2026 to 48% in 2028. But Technoprobe and FormFactor are also expanding capacity; mass production of probe cards typically retains only one or two suppliers, so qualification results directly affect market share.
PCBs are becoming a supply bottleneck for probe cards. MPI plans to raise the share of PCBs made in-house from approximately 5% to 50% in the second half of 2027, but ramping up mass-production yields for high-layer-count, fine-line products is difficult, and lead times for the relevant equipment exceed 12 months; if progress falls behind, added pin capacity could also be constrained by PCB supply.
For CPO testing equipment, the bank assumes MPI captures 50% of the addressable market for wafer-level Insertion 2, and halves the revenue contribution because the process may be eliminated. In its model, this accounts for approximately 3% of revenue in each of 2027 and 2028. Chiplet-level Insertion 3 equipment accounts for approximately 6% of revenue in each of those years.

A probe card’s PCB brings together the current and signals from all pins. Rising pin counts and power make power delivery, heat dissipation and routing more complex, and the PCB is increasingly likely to determine whether the entire card passes qualification. More chip designs also mean more custom PCBs, lengthening lead times.
JPMorgan is positive on test PCB supplier Chunghwa Precision Test Tech: it is seeking to move from supplying PCBs alone to providing complete probe card solutions, whose product value is approximately 3–5 times that of selling PCBs alone. The bank maintains its overweight rating and a target price of NT$4,900.

JPMorgan initiated coverage of WinWay with an overweight rating and a target price for December 2027 of NT$7,500; MPI received a neutral rating and a target price of NT$5,350. The bank expects WinWay’s socket-related earnings per share to grow at a compound annual rate of 108% from 2026 to 2028, and MPI’s overall earnings per share to grow at 73%.
The bank values WinWay and MPI at 26 times and 28 times their respective expected 2028 earnings per share, a 2-multiple premium for probe cards, below the 6–8-multiple gap the report says the market usually applies. Its 2028 earnings-per-share forecast for MPI is NT$194.78, approximately 12% below the market consensus of NT$220.52.
This assessment depends on testing times continuing to rise and AI platforms progressing as planned. If testing efficiency improves faster than expected, or customers shift more testing to wafer probing before packaging, growth in socket demand could slow; project delays could also cause suppliers that have expanded capacity to incur depreciation and personnel costs sooner.