SiC thermal sinking of the core of the core: help high-power laser chips break through the heat dissipation bottleneck

The single light output power of high-power semiconductor laser chips continues to increase, and the current mainstream application has risen to 45W, but when moving towards higher power 50W, 60W or even higher power, the thermal conductivity of ceramic thermal sink, which is the "heat dissipation backing" of the chip, has become a constraint, although the thermal conductivity of AlN ceramics has increased from the previous 170W to the current 230W*K, it has still become a "stumbling block" restricting the breakthrough of chip light output. Dogain uses monocrystalline SiC thermal precipitation independently developed and produced throughout the process, bringing disruptive heat dissipation solutions to the industry.

From "sufficient" to "excellent", cooling technology must come first

The "power enhancement" and "heat dissipation ability" of high-power laser chips have always been a pair of symbiotic propositions. By continuously optimizing the performance of AlN ceramics, mainstream thermal sink manufacturers have increased their thermal conductivity to 230W/m*K, which can meet the heat dissipation needs of chips with optical power of 45W and below. However, when the chip power is higher than 50W, the chip junction temperature increases significantly, the electro-optical efficiency decreases, and the reliability deteriorates.

On the basis of the stable mass production and production of conventional AlN thermal deposition, Dogain has innovatively used high thermal conductivity SiC as the substrate, overcame a series of technical problems such as poor metal adhesion and difficult cutting, and developed SiC thermal sink with a thermal conductivity of ≥ 370W/m*K. Batch application to the packaging of 66W chips, comparative tests show that the junction temperature, divergence angle, polarization (PER) and other indicators of the chip can ensure that the high-power chip is in a stable and efficient operating state.

The output power of the 66W chip in SiC hot-sink packaging is 2W higher than that of AlN hot-sink at 68.5A test current (3% increase), and the chip junction temperature is reduced by 7.5°C. This difference in performance intuitively reflects the significant advantages of SiC heat sink in heat dissipation capabilities, ensuring the long-term reliability of high-power chips.

Four core breakthroughs have created a new height of hot sink technology

(1) Semiconductor-grade metallization and grinding and polishing process is adopted

Relying on the fully automatic process technology developed by semiconductor-grade metallization and grinding and polishing equipment, the thickness, surface roughness and adhesion of the single-sided Cu layer can be accurately controlled, and the thermal expansion coefficient (CTE) of the overall thermal sink can be accurately matched with the chip. This makes the polarization (PER) performance of the chip better, which can effectively improve the coupling efficiency in the subsequent pump source fiber coupling process.

(2) Adopt advanced laser cutting technology

The hardness of single crystal SiC is much higher than that of AlN ceramics, and the high-precision laser cutting process developed by Dogain fundamentally solves the processing problems such as laser residue spatter and cutting misalignment, and accurately controls the Cu pullback in the range of 10~20um. This breakthrough not only improves production efficiency and processing accuracy, but also directly ensures the consistency of the COS eutectic patch link and the stability of the optical coupling process, providing key support for the COS packaging performance of high-power laser chips.

(3) Absolute guarantee of 500V withstand voltage

High-purity intrinsic SiC is used as the substrate to make the heat sink capable of 500V withstand voltage. With unique testing technology, it can accurately identify products with insufficient withstand voltage due to substrate defects during the production process, ensuring that 100% of the thermal sink of each piece has passed the withstand voltage test, providing a guarantee for the overall withstand voltage performance of the pump module.

(4) The ultimate pursuit of quality control in the whole process

From the precise control of key parameters to the quality traceability of the whole life cycle, Dogain has established a rigorous quality control system: precise regulation of AuSn components (75±5wt% Au), stable melting point, and ensuring that the patch program is fixed and unchanged; Through AOI automatic inspection and sorting, combined with the photo and file traceability mechanism, the quality of each piece of hot sink is well documented; Each batch of products is sampled and packaged for testing, and then shipped after verification to ensure the quality of the shipped products in an all-round way.

Sufficient mass production capacity and strong delivery capacity

Today, Dogain SiC thermal sink has been successfully applied to high-end pump source products, and has won the favor of many customers with its excellent performance. This is not only the market's affirmation of our technology, but also marks the entry of the high-power laser chip cooling field into the SiC era.

From breaking through technical bottlenecks to leading industry standards, Dogain will continue to deepen its thermal sink technology, take innovation as the engine, provide stronger heat dissipation support for the development of the high-power semiconductor laser industry, help the industry break through the power limit, and create a new technological future!