ATE, fully known as Automated Test Equipment, is equipment that performs automated testing of functionality and performance after wafer and chip packaging. ATE equipment can perform parameter testing, functional testing, performance testing, fault detection, and reliability testing of chips, playing a vital role in the semiconductor manufacturing process.
ATE PCBs Used in Chip Production Process
As shown in the figure above, different types of ATE testing machines require different ATE boards.
Probe Card: Probe cards are used to test uncut and unpackaged semiconductor devices. By performing electrical testing on each chip on the wafer, devices with parameters within the required range are selected for packaging.
Load Board: Load boards are used on Final Test equipment. Load boards are used to perform functional or performance testing on devices after packaging, screening out defective devices after packaging. For ICs with high-speed interfaces, the corresponding load boards usually have strict impedance requirements.
Burn-in Board (BIB): Burn-in boards are used for aging testing of packaged chips, such as thermal cycling or accelerated switching cycles, to expose early failure faults of devices. The PCB materials for burn-in boards must be able to withstand prolonged and repeated exposure to high-temperature environments, having extremely high reliability.
PCB Processing Requirements for ATE Boards
As integrated circuits (ICs) become smaller and more complex, the density and complexity of ATE test boards also increase accordingly.
Alignment Accuracy and High Aspect Ratio
Load boards typically have more than 30 layers, BGA pitch is usually between 0.35 to 0.5mm, drill-to-conductor distance is less than 4mil, parallel test channels: 4 sites, 8 sites, to 16 sites. This puts forward higher requirements for PCB layer-to-layer alignment, drilling accuracy, copper plating under high aspect ratios, and resin plugging processes.
Ultra-High Density Test Interface
BGA pitch on Probe Cards is typically between 85-200μm, with high-end products ranging from 40-55μm. Fine lines approach packaging substrate levels. When lines exceed PCB process capabilities, MLO/MLC adapter boards using packaging substrate processes are required for transition before testing.
MLO Interposer
Flatness
Probe cards and high-end ATE PCBs have very high requirements for flatness, with warpage rate controlled within 0.1%-0.2%. BGA area pad height differences should be maintained within 50μm (2mil), with stricter requirements keeping the range within 25-28μm (1mil).
Appearance Quality
Since the Device Under Test (DUT) area establishes connections through probes and pads, pads must not have depressions or damage, and pad gold surfaces must not have scratches or roughness issues.
Signal Integrity
High-end ATE boards require impedance tolerance of ±5%, and stub length below 8-12mil. Due to strict impedance requirements, plating, etching uniformity, and back-drilling process capabilities are all required to be very strict.
Sunkey PCB ATE Specialized Product Line
Sunkey PCB has rich experience in manufacturing complex ATE boards, such as high aspect ratio drilling, pulse plating, high flatness control of DUT Pads and PCBs, <.002' layer-to-layer alignment accuracy, ENCAP process, and through-hole bonding technology. Additionally, Sunshine PCB has an advanced PCB technology laboratory that can perform validation and reliability testing of new materials.
Focusing on the characteristics of ATE boards having small batch sizes but requiring rapid delivery, Sunkey PCB has established an efficient delivery process. From DFM communication before manufacturing, engineering preparation, and material preparation, to dedicated production lines during manufacturing and after-sales service after order shipment, we fully meet the cycle requirements of chip R&D and design.
Sunkey PCB ATE Series Boards Introduction
