没有现代 PCB design, high density interconnect (HDI) technology, and of course high-speed components, none of these would be usable. HDI 技术允许设计人员将小组件彼此靠近放置。 更高的封装密度、更小的电路板尺寸和更少的层数给 PCB 设计带来了级联效应。

HDI的优势

Let’s take a closer look at the impact. 增加封装密度使我们能够缩短组件之间的电气路径。 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. 减少层数可以在同一块板上放置更多的连接，并改进组件放置、布线和连接。 从那里，我们可以专注于一种称为每层互连 (ELIC) 的技术，它可以帮助设计团队从较厚的电路板转向较薄的柔性电路板，以保持强度，同时让 HDI 看到功能密度。

HDI PCBS rely on lasers rather than mechanical drilling. 反过来，HDI PCB 设计导致更小的孔径和更小的焊盘尺寸。 减小孔径使设计团队能够增加电路板面积的布局。 缩短电气路径并启用更密集的布线可提高设计的信号完整性并加快信号处理速度。 We get an added benefit in density because we reduce the chance of inductance and capacitance problems.

HDI PCB 设计不使用通孔，而是使用盲孔和埋孔。 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. 您在焊盘上的使用还可以通过减少交叉延迟和寄生效应来减少信号损失。

HDI manufacturability requires teamwork

可制造性设计 (DFM) 需要周到、精确的 PCB 设计方法以及与制造商和制造商的一致沟通。 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. 简而言之，HDI PCBS 的设计、原型制作和制造过程需要密切的团队合作并关注适用于项目的特定 DFM 规则。

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.

了解您的电路板材料和规格

由于 HDI 生产使用不同类型的激光钻孔工艺，设计团队、制造商和制造商之间的对话在讨论钻孔工艺时必须关注板的材料类型。 提示设计过程的产品应用程序可能具有尺寸和重量要求，从而使对话朝着一个方向或另一个方向发展。 High frequency applications may require materials other than standard FR4. 此外，有关 FR4 材料类型的决定会影响有关钻井系统或其他制造资源选择的决定。 虽然有些系统很容易钻穿铜，但其他系统不能始终如一地穿透玻璃纤维。

除了选择正确的材料类型外，设计团队还必须确保制造商和制造商可以使用正确的板厚和电镀技术。 With the use of laser drilling, the aperture ratio decreases and the depth ratio of the holes used for plating fillings decreases. 尽管较厚的板允许较小的孔径，但项目的机械要求可能指定较薄的板，这些板在某些环境条件下容易发生故障。 设计团队必须检查制造商是否有能力使用“互连层”技术并在正确的深度钻孔，并确保用于电镀的化学溶液会填充孔。

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. 由于 ELIC，PCB 设计可以利用高速电路所需的密集、复杂的互连。 由于ELIC使用堆叠的填铜微孔进行互连，因此可以在任何两层之间进行连接，而不会削弱电路板。

元件选择影响布局

与制造商和制造商就 HDI 设计进行的任何讨论还应侧重于高密度组件的精确布局。 The selection of components affects wiring width, position, stack and hole size. 例如，HDI PCB 设计通常包括密集球栅阵列 (BGA) 和需要引脚逃逸的精细间距 BGA。 在使用这些设备时，必须认识到损害电源和信号完整性以及电路板物理完整性的因素。 这些因素包括在顶层和底层之间实现适当的隔离，以减少相互串扰和控制内部信号层之间的 EMI。Symmetrically spaced components will help prevent uneven stress on the PCB.

Pay attention to signal, power and physical integrity

除了提高信号完整性之外，您还可以增强电源完整性。 由于 HDI PCB 使接地层更靠近表面，因此提高了电源完整性。 板的顶层有接地层和电源层，可以通过盲孔或微孔与接地层相连，减少平面孔的数量。

HDI PCB 减少了穿过板内层的通孔数量。 In turn, reducing the number of perforations in the power plane provides three major advantages:

较大的覆铜面积将交流和直流电流馈入芯片电源引脚

L resistance decreases in the current path

L 由于低电感，正确的开关电流可以读取电源引脚。

Another key point of discussion is to maintain minimum line width, safe spacing and track uniformity. 在后一个问题上，在设计过程中开始实现均匀的铜厚和布线均匀性，并进行制造和制造过程。

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.

建立并应用特定的设计规则

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. 制定详细的设计规则有助于为您的电路板选择合适的制造商或制造商，并为团队之间的沟通奠定基础。