— A Record of the Successful Development of Benqiang Circuit's 24-Layer 6-Stage Arbitrary Interconnection HDI Board"
With the continuous development of the integrated circuit industry, the connections between chips have become increasingly complex. Traditional PCB technology faces limitations in applications with rising frequency and speed requirements. Achieving stable and reliable connections between high-speed and high-density chips has become crucial. Moreover, as chip power consumption continues to increase, the associated heat generation has also risen, necessitating an effective cooling system to maintain the normal operation of the chips. Thus, the Interposer PCB, a new type of PCB, has emerged.
The so-called Interposer PCB is a highly precise, high-layer arbitrary interconnection HDI PCB. It serves as a key component for connecting and integrating different electronic components, functioning as an intermediate layer for chip connections. It achieves electrical connections through lead pads and interconnects with the chip's micro-bumps (uBump) and wiring within the intermediate layer. The intermediate layer utilizes Through-Silicon Vias (TSV) to interconnect the upper and lower layers. The PCB design features laser microvias and dense routing converging to the outer layer, resulting in a multi-structure with BGA connections on the top surface and pads on the bottom surface.
Interposer PCB has exceptional value and significance in improving various performance aspects of integrated circuits.
First, Interposer PCB can provide higher connection speeds and reliability for semiconductor products. Made from high-performance materials, Interposer PCBs enable short-distance, high-density connections between integrated circuits, significantly increasing the data transfer rates of chips.
Second, Interposer PCB technology addresses signal integrity and power consumption issues. By utilizing Interposer technology, signal pins can be directly connected to the Interposer layer, thereby reducing the length of signal transmission paths, minimizing signal loss, and enhancing signal integrity.
Third, the Interposer layer can also serve as a cooling solution, effectively lowering chip temperatures.
Finally, Interposer PCB technology facilitates connections between heterogeneous integrated circuits. By placing integrated circuits with different functions on the same Interposer layer, interconnections between different chips can be achieved, thus enhancing the overall performance and efficiency of semiconductor products.
In summary, Interposer PCB is widely used in fields such as high-performance computing, artificial intelligence, data centers, and communications. In high-performance computing systems, Interposer technology enables the connection of multiple computing chips, achieving greater computational capacity. In the field of artificial intelligence, Interposer technology facilitates interconnections between different chips, enhancing the training and inference speed of neural networks. In data center and communication applications, Interposer technology provides higher transmission rates and bandwidth to meet the demands of big data processing and high-speed communication.
As a leading domestic manufacturer of high-end HDI PCB rapid prototyping, Benqiang Circuit keeps pace with market trends. In response to the urgent demand from clients for high-layer arbitrary interconnection (Anylayer) HDI boards, the Product Research Institute has dedicated itself to research and overcoming technical challenges, ultimately achieving the successful development of this type of Interposer PCB—high-layer high-level arbitrary interconnection HDI board.
Below, we will disclose information about this high-precision circuit product using the 24-layer 6-stage Anylayer HDI PCB as an example.
Basic Product Parameters
| Layer Count |
24
|
Material |
S1000-2M |
| Board Thickness |
2.25mm |
Impedance Tolerance |
50Ω +/- 5Ω |
| Blind Via Diameter
|
4mil |
Pressing Cycles |
7 |
| Line Width/Spacing |
2.4/3mil |
BGA Diameter |
8mil |
Product Structure
Process Challenges
Challenge 1
The thickness of the buried vias from L7 to L18 is 1.0mm, with a mechanical via diameter of 0.1mm, resulting in a hole diameter ratio of 10:1, making mechanical drilling difficult.
Challenge 2
The BGA pitch is 0.35mm, with a distance of 0.13mm from the hole to the conductor line. Multiple pressing cycles can easily lead to misalignment.
Challenge 3
The line width/spacing is 2.4/3mil, and the routing is dense. Below are some routing diagrams:
Finished Product Photo
As one of the early companies engaged in the research and manufacturing of high-difficulty HDI PCBs, Benqiang Circuit, founded in 2010, has long focused on achieving high reliability and precision in HDI PCB processes. Over the past decade, the company has consistently refined its fine wire and microvia technologies. By integrating these advancements with flexible manufacturing paradigms, Benqiang has developed a self-driven technological approach that continually optimizes processes, breaks manufacturing bottlenecks, and enhances operational efficiency and product throughput. This approach ultimately ensures Benqiang Circuit's leading position in terms of process capability and delivery cycle for small-batch HDI boards and engineering sample boards.
