HDI PCB – Learn about the benefits and applications

With so many different types of printed circuit boards on the market, determining which one is right for your next project can be a challenge. In this article, we explore a more common option – the high-density interconnect PCB.

What is HDI PCB?
HDI PCBs feature thinner lines, closer spaces, and denser routing, allowing for faster connections while reducing project size and volume. These boards also feature blind and buried vias, laser drilled microvias, sequential lamination, and vias in pads.

HDI vs Standard PCB – What’s the Difference?
HDI PCBs offer better signal integrity and have higher layers than standard PCBs. They also result in higher density (and therefore smaller) PCBs.

HDI PCBs have laser micro-vias, while standard PCBs only have mechanical drilling.

Additionally, Ball Arrays (BGAs) are defined by the number of pins (or connections) connected to the board. As the pin count increases, you need a microvia almost 100% of the time.

HDI PCB Applications
HDI PCBs are used in a variety of applications, including:

Electronics for the automotive industry (navigation, GPS, etc.)
Smartphones and Cell Phones
Game host
Wearable technology (Apple Watch, fitness trackers, etc.)
Military and Aerospace
Benefits of HDI Printed Circuit Boards
Whether you should have an HDI PCB is usually up to the designer. The benefits of this board include:

cost effective
Better signal integrity/high speed (you get more out of this board package without having to use multiple PCBs)
better signal
compact design
high frequency
HDI through In-Pad filling process
This refers to a specialized copper plating process. It is different from the via fill process within the pads of non-HDI standard PCBs.

HDI Lamination and Material Process
Laminates must have high temperature capability as they need to withstand at least three lamination cycles. Isola, Panasonic and Megtron all produce such materials.

Questions about HDI PCBs?
We have the experience and knowledge to do all complex PCB work – including HDI fabrication and fabrication. As one of the leading HDI PCB manufacturers, we continue to invest in state-of-the-art production and testing technology. We also have deep engineering experience and can handle all types of jobs with incredible accuracy – on time and on budget.

If you are looking for more information, please contact us or visit our HDI PCB page to learn about our capabilities, manufacturing tolerances, certifications and more.

Improvement measures for the drop of the board-to-board connector (B2B connector)




后来我们选择先实施第四个方案,在连接器的焊脚上加环氧树脂胶,因为我们认为前两步对改进的作用不大,第三步会造成以后的维修困难。至于环氧树脂胶水的选择,我们选择了“Cemedine”的Super-X 8008,因为这款胶水已经用在我们其他产品中,这是一种单组份的胶水,Work Bear个人认为和硅胶差不多我们通常在厨房里想要和使用的口香糖。使用前就像牙膏一样,干燥后略微柔软有弹性。


不过,在市场不断传出板对板连接器掉线的问题后,也就是说如果不改进设计加强掉应力的问题,单靠点胶是无法解决这个问题的,加上科钦是一件很头疼的事。只是时间给自己耽搁了,因为加胶后能承受的应力增加还是有限的,我们最后设计了一个额外的胶框,在电路板上开了几个NPTH定位孔,把板子和板子连接起来. 这不是一个小项目,因为电路板的设计需要移动。

Circuit Board to Board Edge Board Cutting Board: Stamp Hole Design

“邮票孔”拆分的最大优点是不需要任何特殊的拆分工具即可达到拆分的目的,不像其他两种方法需要专用的Scoring machine和routing machine。但是,这个邮票孔确实有很多缺点。以下是缺点:


The following are two different stamp hole designs. Have you noticed the difference? The same is the design of 5 small stamp holes with a diameter of 1.0mm, but the result is very different. The bad stamp hole design causes residues after the PCB is divided. The burrs protrude beyond the molding line. For precision products, most of these burrs require extra manpower to be processed and smoothed, which not only wastes manpower, but also wastes man-hours, increases costs, and may contaminate the powder during grinding. other products.
The difference between the two stamp hole designs is basically only in the design position of the rib. The better stamp hole design has the edge of the rib just in the middle of the stamp holes on the two sides, so that the stamp holes on the two sides are pre-formed broken In this way, it is not only easier to break the edge of the board, but also less burrs beyond the forming line after the edge of the board is broken.
Poorly designed circuit board [stamp hole]
The stamp hole design is not good, and the protruding point burrs after the plate are separated out of the forming line, which requires manual post-processing and smoothing. (The photo on the left appears to be a three-hole stamp hole design, but the result is the same)
印章孔设计不好,分版后突出点毛刺,毛刺超出成型线,需要人工进行后处理和修光,既浪费人力,又浪费工时,增加成本. 螺纹需要人工进行后处理和修光,不仅浪费人力,而且浪费工时,增加成本,而且磨削时的切屑还可能污染其他产品。
Better Design 电路板【印章孔】

Introduction to functional testing after board assembly (FVT/FCT)

PCB组件的功能测试一般称为F( Function Verification Test,功能验证电路)测试(Function Test,Function Test,Function Test,Function Test,Function Test,功能测试)设备板的形状也可以用于设备设备后发现的缺陷,所有浪费的工时进行拆解处理损失。
此功能测试的可能会因和产品的大小和不同而不同。时间紧迫等程度、测试板数量、成本不同有不同的选择。据了解,Work Bear和常用的功能测试方法大致可以分为以下几类。测试方法:

最大的问题是容易损坏的标准(GOLDEN SAMPLE),因为电路板或者电路板之间的一些连接器无法承受过多的电路板,通常采用延长线。优点可以方便地扩展连接器,这样就另起炉灶了。另外,延长线路便宜且所有板子不能正常更换功能。比用坏掉的信号换换更特殊的划算。扫描器、当触摸屏

▼ 下图是ICT测试机。基本上,FCT/FVT和它差不多,但是会有外接屏幕和按钮。下面会有一些FVT的照片。

FVT 功能测试夹具内的电缆
缺点是成本高,因为需要做定制板,所以这种无线功能测试治具的成本一般比一般的针床功能测试治具高40%到70%左右,而且只有适用于大量 可以生产稳定的产品,因为移动到测试点的电路板的任何设计更改都必须重新构建为定制电路板。
(Wireless FVT) 这是一款无线功能测试机,改进了传统的功能测试治具。夹具的顶部由定制的电路板代替,以代替原来的电缆。该夹具还具有集成产品的功能夹具。多于。
(无线F)功能测试电路要设置在待测电路板上后盖板的位置。以机台内部为目的。 ▼这是无线测试治具的整机结构。用功能中没有集成电缆

Advantages and Disadvantages of Selective Wave Soldering Machine

,虽然电路板的价格可以通过 SMT 工艺,但本身有一些工艺可以通过通孔插入(Past-In)。 – 或 PIPHole ) 技术可以通过 SMT 技术让所有工艺通过 SMT 制造,通过所有工艺让所有工艺使用或焊接,但也不是通过所有订单技术,都可以使用,但也不是通孔订单播放机”的出现“波峰焊”。


焊接良好的焊接质量和通孔率。 炉子节省时
。高温峰焊那样使用熔焊(老)。 热点区域的焊接波峰焊
必须额外购买 MT 的工艺,但可以与 SMT的工艺相比,可以继续运行一次。但是需要编写程序缺点,剩余时间就可以制作了。如果你写了,你可以重复使用它。

Causes and prevention methods of PCB board bending



由于大部分回流焊炉都是用链条带动电路板前进,较大尺寸的电路板会因自重在回流焊炉内凹陷变形,所以尽量把电路板的长边作为板边. 在回流焊炉的链条上,可以减少因电路板本身重量引起的凹形变形。这也是减少面板数量的原因。也就是说,在通过炉膛时,尽量用窄边与炉膛方向垂直,这样可以达到最低的凹变形量。

如果单层托盘夹具不能减少电路板的变形,则需要加一层盖板与上下托盘夹住电路板,通过回流焊可以大大减少电路板的变形烤箱。. 但是,这种烤箱托盘非常昂贵,您必须增加人工来放置和回收托盘。

Introduce PCBA double-sided reflow process (SMT) and precautions for component placement







哪些 SMT 零件应该通过第二面的回流炉?这应该是重点。

Large components or heavier components should be placed on the second side to avoid the risk of parts falling into the reflow oven during reflow.
LGA and BGA parts should be placed on the second side as far as possible to avoid the risk of unnecessary re-melting of tin during the second pass, so as to reduce the chance of empty/false soldering. If there are thin feet and smaller BGA parts are not excluded, it is recommended to place them in the reflow oven on the first side.

Whether the BGA should be placed on the first side or the second side through the reflow oven has been controversial in the electronics manufacturing industry. Although placing the second side can avoid the risk of re-melting tin after the second reflow, but usually when the second side passes through the reflow oven, the PCB will be deformed more seriously, which will affect the quality of tin eating, so the work bear will say It is not ruled out that the BGA with thin feet can be considered on the first side. But on the other hand, if the PCB has been seriously deformed, as long as it is a thin-footed part, placing it on the second side for patching must be a big problem, because the solder paste printing position and amount of solder paste will become extremely inaccurate. So the focus should be on how to avoid PCB deformation, instead of considering placing BGA on the first side because of deformation, right?
The deformation of the board will not only affect the quality of the parts eating tin, but also make the BGA fail when it is assembled into the whole machine. Because the board is erected when the board is assembled, the board is not deformed, so it will try to restore the deformed board to its original state. deformed condition.
Parts that cannot withstand too many high temperatures should be placed on the second side to pass through the reflow oven. This is to prevent the parts from being damaged by too many high temperatures.
The parts of PIH/PIP should also be placed on the second side to pass the furnace. Unless the length of the solder feet does not exceed the thickness of the board, the feet protruding from the surface of the PCB will interfere with the steel plate on the second side, which will cause the second side The solder paste printed steel plate cannot be flatly attached to the PCB, resulting in abnormal solder paste printing.
Some components may use soldering inside, such as a network cable connector with LED lights. It is necessary to pay attention to whether the temperature resistance of this part can pass through the reflow oven twice. If not, it must be placed on the second side.
It is only that the parts are placed on the second side and the patch has been passed through the reflow oven, which means that the circuit board has passed the baptism of the high temperature of the reflow oven. At this time, the circuit board has been somewhat warped and deformed, that is to say, the tin The printing amount and printing position of the paste will become more difficult to control, so it is easy to cause problems such as empty soldering or short circuit. Therefore, it is recommended not to place 0201 and fine spacing for the parts that are placed on the second side to pass the oven. pitch) parts, BGA should also try to choose solder balls with larger diameters.

目前,电路板的焊接工艺大致可分为全板焊接和局部焊接。全板焊接大致分为回流焊和波峰焊,而电路板的部分焊接包括载波波峰焊(Carrier Wave Soldering)、选择性焊接、非接触激光焊接等。

Introduction to the structure and function of PCB board

Today’s PCB substrate outsole is composed of three main components: copper foil layer (Copper Foil), reinforcement (Reinforcement), and resin (Epoxy). Powder (Fillers) was added to the PCB in large quantities to improve the heat resistance of the PCB.
We can think of copper foil as the blood vessels of the human body, which are used to transport important blood and allow the PCB to function; the reinforcing material can be imagined as the bones of the human body, which is used to support and strengthen the PCB so as not to slack off; and Resin can be imagined as the muscle of the human body and is the main component of PCB.
The uses, characteristics and precautions of these four PCB materials are explained below:
1. Copper Foil (copper foil layer)
Electric Circuit: Conductive circuit.
Signal line: The signal (signal) line that transmits the message.
Vcc: power layer, working voltage. The working voltage of the earliest electronic products was mostly set to 12V. With the evolution of technology and the requirement of power saving, the working voltage has gradually become 5V and 3V, and now it is gradually moving to 1V, and the requirements for copper foil are also increasing. Come higher.

GND (Grounding): ground plane. Think of Vcc as a water tower in the home. When we turn on the faucet, water (electrons) will flow out through the pressure of the water (working voltage), because the actions of electronic parts are determined by the flow of electrons. GND can be imagined as a sewer, all used or unused water will flow away through the sewer, otherwise the faucet will keep draining and the house will be flooded.
Heat Dissipation (due to high thermal conductivity): for heat dissipation. Have you ever heard that some CPUs are so hot that they can cook eggs? This is not an exaggeration. Most electronic components consume energy to generate heat. At this time, a large area of ​​copper foil needs to be designed to release the heat to the air as soon as possible. Among them, otherwise not only human beings can’t stand it, but even electronic parts will also crash.
2. Reinforcement
When choosing a PCB reinforcement material, it must have the following excellent characteristics. Most of the PCB reinforcing materials we see are made of glass fiber (GF, Glass Fiber). If you look closely, the material of glass fiber is a bit like a very thin fishing line. Because of the following individual advantages, it is often selected. When the basic material of PCB.
High Stiffness: With high “rigidity”, the PCB is not easily deformed.
Dimension Stability: Has good dimensional stability.
Low CTE: It has a low “thermal expansion rate” to prevent the circuit contacts inside the PCB from detaching and causing failure.
Low Warpage: It has low deformation, that is, low plate bending and plate warpage.
High Modules: High “Young’s modulus”
3. Resin Matrix (resin mixture)
The traditional FR4 sheet is mainly based on Epoxy (epoxy resin), while the LF (Lead Free)/HF (Halogen Free) sheet uses a combination of various resins and different curing agents, which increases the cost. LF is about 20%, and HF is about 45%. .
HF sheet is brittle and easy to crack, and the water absorption rate increases. Thick and large sheets are prone to CAF. It is necessary to use open fiber cloth and flat fiber cloth, and strengthen the impregnated material.
A good resin must have the following conditions:
Heat Resistance: Good heat resistance. The heat resistance is good if the board will not explode after two to three times of heating and welding.
Low Water Absorption: Low water absorption. Water absorption is the main cause of PCB explosion.
Flame Retardance: Must be flame retardant.
Peel Strength: Has high “tear strength”.
High Tg: High glass transition point. Most of the materials with high Tg are not easy to absorb water, and the lack of water absorption is the fundamental reason for not breaking the board, not because of high Tg PCB.
Related reading: What is glass transition temperature (Tg, Glass Transition Temperature)
Toughness: Good “toughness”. The greater the toughness, the less likely it is to burst. Toughness is also known as “destruction energy”, and the tougher the material, the stronger the ability to withstand impact and damage.

Dielectric properties: High dielectric properties, that is, insulating materials.
4. Fillers System (powder, filler)
In the early days of lead soldering, the temperature was not very high, and the original board of the PCB was still tolerable. Since the lead-free soldering was used, the temperature increased, so the powder was added to the PCB board to make the PCB strong against temperature.
Fillers should be coupled first to improve dispersion and adhesion.
Heat Resistance
Low Water Absorption
Flame Retardance
High Stiffness
Dimension Stability
Low Warpage
Drill processability: Due to the high rigidity and high toughness of the powder, it is difficult to drill a PCB.
High Modulus: Young’s modulus
Heat Dissipation(due to high thermal conductivity): for heat dissipation.

Real cause analysis and preventive measures of PCB explosion

PCB线路板 出现爆米花或脱层的主要原因无非是①板子吸水率②α2/z-CTE过大,而板子吸水引起的爆米花占了对于70% %的次品,其他原因如PCB结构膨胀收缩不均匀、加热冷却不均匀、工艺损坏、发黑不良……虽然不能排除这种可能性,但比例不会太高。


由于“水”是PCB爆炸的主要原因,所以大部分爆炸问题可以通过去除PCB中的水分来解决,而【烘烤】是去除PCB的最佳方法。 PCB 外部的水分。由于烘烤的目的是去除水分,因此烘烤条件最好满足以下要求:
PCB层压过程控制。对于PCB层压后烘烤后的多层板,可取样品用相同的方法和相同的机器测量两次Tg值;如果Tg 2 -Tg 1 的△Tg超过2~3°C(视差值而定),则表示层压过程的固化反应(硬化包括聚合和交联)尚未到位,而这种未固化的板材很容易吸水,容易开裂。

存放超过三个月的多层 PCB 可能会经历应力(来自压制)集中行为和吸水事实(这会增加 Z 膨胀)。应做好焊前烘烤(105℃+24小时)的防爆措施,或将一叠50块手机板压入氮气中185℃+70PSI烘烤2小时。客户端3个月以上的板子会先烘烤再焊接,这样可以减少板子的爆炸。烘烤不仅会增加成本,而且对 OSP 也是不利的。烘烤时,需要单独烘烤,以利于水分充分排出。





AOI最大的优点是可以对MT炉的人工眼目检测,比人更准确地判断SMT设备和圈组件的设备眼光一样,但AOI完全可以对人眼进行检测,只要能看到。当然,可以的位置,可以在下面检测到的正确度数,可以有更多的管子到的,我可以有更多的形状来检测 IC 的更多隐藏的能力,我的脚可能会提供更多的检测,会提供更多的检测率,但确实有10%的光检测率很容易出现

因此,一般的电路板组件和保证生产线很少只使用 AOI 来其组件质量,而且通常经过 ICT(在线测试)测试(FVT)测试,并且某些生产线会额外增加一个 AXI(自动 X- ray Inspection) 的 X-Ray 检查线路上确保使用 B 的焊接点(如 GA)的,电路板能够达到 100% 的测试质量。

AOI 能出出组件电路板的那些检测功能吗?



通过AOI的脚部翘曲的明暗差异来袭,但也可能有可能的足部翘曲变形。 AOI_Lift_leadAOI_Lead_Defect隐藏一般来说,很容易检查,如果是在下面的供应商处,就无法避免锡桥。例如,一些连接的AOI_solder_bridge 焊料不足):当锡量严重不足时,当然可以用AOI轻松判断的办法,锡膏印刷量联盟出现一些AOI_insi_derder 只是冷焊:一定最烦人通常从外表上做出来的假焊或冷焊。外观和形状来判断,用这样的真实世界。可以有效地提高SMTSMT质量,即时操作,提高,准确