In Chizhou, Anhui Province, the subsidiary of Yunzhong Technology, Chizhou Yunhai Ceramic Capacitor Technology Co., Ltd., has made a new breakthrough in the field of high-power laser heat sinks by leveraging the DPC (Direct Copper Plating) ceramic substrate technology. In 2025, the monthly shipment volume of Chizhou Yunhai laser heat sinks exceeded 3 million units, and the customers included leading domestic laser equipment companies. Recently, the reporter conducted an exclusive interview with the general manager of Chizhou Yunhai, Liu Xingxing, and the chairman of Yunzhong Technology, Wang Bin, in an attempt to reveal the technical path and industrial blueprint of this enterprise. 

The "three-layer barrier" of the DPC process 

There are three main mainstream routes for metalization of ceramic substrates - DBC, AMB and DPC. Yunzhong Technology has chosen the DPC route, which has advantages such as high precision patterning (line width precision reaching 25 micrometer level) and vertical interconnection capability. Through the "via metalization" process, it enables the connection of circuits on the upper and lower layers, significantly shortening the signal and heat conduction paths. 

However, the technical barriers of this process have deterred most entrants, mainly in three aspects. 

Firstly, the deep-hole metallization process is more advanced than through-hole metallization. This process requires the construction of a continuous and defect-free conductive layer within a vertical micro-hole channel that is ten times deeper than the diameter. It is necessary to first completely and uniformly coat a seed layer on the inner wall of the deep hole using magnetron sputtering, then fill it with copper through electroplating. Precise control of parameters such as current density and temperature is required to balance the deposition rates inside and outside the hole, avoiding the formation of intractable voids. 

Secondly, the mismatch of material thermal expansion coefficients causes significant differences in thermal expansion coefficients between ceramics and copper. Repeated thermal expansion and contraction at the interface will generate extremely high thermal stress. "After multiple cycles, it may lead to layer separation, cracking, or even detachment of the copper layer," Liu Xingxing said. The pores or cracks at the interface will also cause the active metals such as titanium, which serve as a buffer layer, to oxidize, seriously affecting the adhesion. Chizhou Yunhai has carried out systematic technical research on technical difficulties such as stress control and has obtained relevant patents. 

Thirdly, for high-precision graphic etching, after metallization, the excess copper layer needs to be "erased" to leave only the precise circuit patterns. This step determines the high-precision wiring level of DPC and requires extremely strict control over parameters such as etching solution concentration, temperature, and spray pressure. 

Closed-loop layout empowers industrialization 

Among the domestic DPC ceramic substrate enterprises, those that possess a complete closed-loop capability covering the entire process from product design, laser processing, yellow light lithography, electrochemistry, PVD (physical vapor deposition) deposition, planarization, surface treatment, and precious metal recovery are few and far between. Chizhou Yunhai is one of them. 

Liu Xingxing explained that the DPC process is a series of interrelated steps, and any fluctuation in any one of these steps could be transmitted to the final product. "The uniformity and adhesion of PVD sputtering coating are the basis for subsequent electroplating and etching. If this step is not controlled properly, no matter how well the subsequent processes are carried out, it will be of no use." In the DPC process, PVD coating is widely recognized as the most difficult step. The uniformity of the thickness of the precious metal coating and the bonding strength of multiple metal layers at the interface are also key difficulties. 

The direct benefit brought by the full-process in-house production is the full lifecycle management of precious metals. Yunhai in Chizhou incorporates precious metal recycling into a closed loop, recovering gold, platinum, etc. from waste materials and purifying them to high purity. According to the company, the recovery rate of precious metals is at a relatively high level in the industry, and it has basically achieved a material closed loop from recycling to purification and then to the preparation of high-purity target materials. This capability has significantly improved the overall utilization rate of materials compared to the industry average. 

The self-developed and self-made automation equipment also played a significant role. The company independently developed high-precision automatic dish placement, automatic visual inspection, automatic laser cutting, and automatic hole detection. This not only ensured product consistency but also effectively reduced labor costs and improved production efficiency. 

At the organizational management level, Yunhai in Chizhou implements performance distribution based on value contribution. The core processes are divided into autonomous operating units, and employees are responsible for output, quality, and cost and participate in the distribution. "These nine words - 'visible, calculable, obtainable' - are crucial," Liu Xingxing said. The combination of high value-added products and high automation levels, along with efficient organizational management efficiency, has laid the physical foundation for the continuous increase in per capita monthly output. In the future, equipment self-production will evolve from "discrete automation" to "full-process data integration and MES intelligent scheduling". 

Expanding applications open up growth opportunities 

When it comes to the market potential of the DPC business, Chairman Wang Bin provided a more vivid assessment: "DPC is a brand-new scene that is gradually improving. Looking back from the vantage point of the industry, China's semiconductor power devices are undergoing a crucial leap from 'usable' to 'efficient'." 

Currently, the products in Chizhou Yunhai mainly consist of pre-fabricated nitrogenized aluminum, beryllium oxide, silicon carbide and other ceramic heat sinks. They are applied in scenarios such as fiber laser, semiconductor laser medical treatment, ultra-fast laser, etc., covering areas like high-power industrial lasers, lighting, medical aesthetics, consumer electronics, and high-end equipment research. Among them, the laser field contributes the main revenue. 

“A considerable proportion of lasers worldwide are produced in China. Many components of the lasers have been made domestically. Chizhou Yunhai has made positive progress in this field.” Liu Xingxing explained. Previously, this market was dominated by overseas enterprises. After Chizhou Yunhai entered the market, its market position significantly improved. 

However, Liu Xingxing's vision did not remain confined to this. "High-power laser heat sink is just the starting point. The application boundaries of DPC are far larger than what is currently seen." The May industry weekly report of Fangzheng Securities stated, "Ceramic materials have high thermal conductivity and a thermal expansion coefficient that is relatively matched with Si. Currently, the technological penetration pace in the fields of optical modules and PCB is expected to accelerate." At present, the company is also actively expanding several new tracks, including T/R component casings for active phased array antennas and high-heat dissipation substrates in the field of optical communications. To meet the demands of product upgrades and emerging fields, the company is actively promoting the construction of related technological renovation and expansion projects, planning to carry out automated and intelligent upgrades of the DPC business production line, and accelerating the realization of large-scale development of ceramic heat sinks and other products. 

Source: China Securities Journal 

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