沒有現代 PCB design, high density interconnect (HDI) technology, and of course high-speed components, none of these would be usable. HDI 技術允許設計人員將小組件彼此靠近放置。 Higher package density, smaller board size and fewer layers bring a cascading effect to PCB design.

HDI的優勢

Let’s take a closer look at the impact. 增加封裝密度使我們能夠縮短組件之間的電氣路徑。 With HDI, we increased the number of wiring channels on the inner layers of the PCB, thus reducing the total number of layers required for the design. 減少層數可以在同一塊板上放置更多的連接，並改進組件放置、佈線和連接。 From there, we can focus on a technique called interconnect per Layer (ELIC), which helps design teams move from thicker boards to thinner flexible ones to maintain strength while allowing THE HDI to see functional density.

HDI PCBS rely on lasers rather than mechanical drilling. 反過來，HDI PCB 設計導致更小的孔徑和更小的焊盤尺寸。 減小孔徑使設計團隊能夠增加電路板面積的佈局。 縮短電氣路徑並啟用更密集的佈線可提高設計的信號完整性並加快信號處理速度。 We get an added benefit in density because we reduce the chance of inductance and capacitance problems.

HDI PCB designs do not use through holes, but blind and buried holes. Staggered and accurate placement of burial and blind holes reduces mechanical pressure on the plate and prevents any chance of warping. In addition, you can use stacked through-holes to enhance interconnect points and improve reliability. 您在焊盤上的使用還可以通過減少交叉延遲和寄生效應來減少信號損失。

HDI manufacturability requires teamwork

可製造性設計 (DFM) 需要周到、精確的 PCB 設計方法以及與製造商和製造商的一致溝通。 As we added HDI to the DFM portfolio, attention to detail at the design, manufacturing, and manufacturing levels became even more important and assembly and testing issues had to be addressed. 簡而言之，HDI PCBS 的設計、原型製作和製造過程需要密切的團隊合作並關注適用於項目的特定 DFM 規則。

One of the fundamental aspects of HDI design (using laser drilling) may be beyond the capability of the manufacturer, assembler, or manufacturer, and requires directional communication regarding the accuracy and type of drilling system required. Because of the lower opening rate and higher layout density of HDI PCBS, the design team had to ensure that manufacturers and manufacturers could meet the assembly, rework and welding requirements of HDI designs. Therefore, design teams working on HDI PCB designs must be proficient in the complex techniques used to produce boards.

了解您的電路板材料和規格

由於 HDI 生產使用不同類型的激光鑽孔工藝，設計團隊、製造商和製造商之間的對話在討論鑽孔工藝時必須關注板的材料類型。 提示設計過程的產品應用程序可能具有尺寸和重量要求，從而使對話朝著一個方向或另一個方向發展。 High frequency applications may require materials other than standard FR4. In addition, decisions about the type of FR4 material affect decisions about the selection of drilling systems or other manufacturing resources. While some systems drill through copper easily, others do not consistently penetrate glass fibers.

除了選擇正確的材料類型外，設計團隊還必須確保製造商和製造商可以使用正確的板厚和電鍍技術。 With the use of laser drilling, the aperture ratio decreases and the depth ratio of the holes used for plating fillings decreases. 儘管較厚的板允許較小的孔徑，但項目的機械要求可能會指定較薄的板，這些板在某些環境條件下容易發生故障。 設計團隊必須檢查製造商是否有能力使用“互連層”技術並在正確的深度鑽孔，並確保用於電鍍的化學溶液可以填充孔。

Using ELIC technology

The DESIGN of HDI PCBS around ELIC technology enabled the design team to develop more advanced PCBS, which include multiple layers of stacked copper filled microholes in the pad. 由於 ELIC，PCB 設計可以利用高速電路所需的密集、複雜的互連。 由於ELIC使用堆疊的填銅微孔進行互連，因此可以在任何兩層之間進行連接，而不會削弱電路板。

Component selection affects layout

與製造商和製造商就 HDI 設計進行的任何討論還應側重於高密度組件的精確佈局。 The selection of components affects wiring width, position, stack and hole size. 例如，HDI PCB 設計通常包括密集球柵陣列 (BGA) 和需要引腳逃逸的精細間距 BGA。 在使用這些設備時，必須認識到損害電源和信號完整性以及電路板物理完整性的因素。 這些因素包括在頂層和底層之間實現適當的隔離，以減少相互串擾和控制內部信號層之間的 EMI。Symmetrically spaced components will help prevent uneven stress on the PCB.

Pay attention to signal, power and physical integrity

除了提高信號完整性之外，您還可以增強電源完整性。 由於 HDI PCB 使接地層更靠近表面，因此提高了電源完整性。 The top layer of the board has a grounding layer and a power supply layer, which can be connected to the grounding layer through blind holes or microholes, and reduces the number of plane holes.

HDI PCB 減少了穿過板內層的通孔數量。 In turn, reducing the number of perforations in the power plane provides three major advantages:

較大的覆銅面積將交流和直流電流饋入芯片電源引腳

L resistance decreases in the current path

L Due to low inductance, the correct switching current can read the power pin.

Another key point of discussion is to maintain minimum line width, safe spacing and track uniformity. 在後一個問題上，在設計過程中開始實現均勻的銅厚和佈線均勻性，並進行製造和製造過程。

Lack of safe spacing can lead to excessive film residues during the internal dry film process, which can lead to short circuits. Below the minimum line width can also cause problems during the coating process because of weak absorption and open circuit. Design teams and manufacturers must also consider maintaining track uniformity as a means of controlling signal line impedance.

建立並應用特定的設計規則

High-density layouts require smaller external dimensions, finer wiring and tighter component spacing, and therefore require a different design process. The HDI PCB manufacturing process relies on laser drilling, CAD and CAM software, laser direct imaging processes, specialized manufacturing equipment, and operator expertise. The success of the entire process depends in part on design rules that identify impedance requirements, conductor width, hole size, and other factors that affect the layout. 制定詳細的設計規則有助於為您的電路板選擇合適的製造商或製造商，並為團隊之間的溝通奠定基礎。