가장 일반적인 PCB 결함 및 해결 방법

PCB에는 많은 문제가 있지만 그 중 일부는 다른 문제보다 덜 분명합니다. 이러한 문제를 구현 실패라고 하며 진단을 위해서는 전문 지식이 필요합니다. 예를 들어 정전기 방전, 화학물질 누출, 패드 들뜸, 부품 이동 등이 모두 고장의 원인이 될 수 있습니다. 고장 모드를 식별하려면 PCB가 고장날 때까지 스트레스 테스트를 수행해야 합니다.

정전기 방전

정전기 방전(ESD)은 전자 회로에서 흔히 발생하는 문제입니다. 전자 부품의 잘못된 취급이나 과도한 전압 레벨로 인해 발생합니다. 대부분의 경우 이로 인한 손상은 잠재적이거나 치명적입니다. 이 문제로 인해 PCB가 부분적으로 또는 완전히 오작동할 수 있습니다.

정전기 방전을 감지하고 수리하는 방법에는 여러 가지가 있습니다. 이 중 일부는 눈에 보이고 제품 성능에 영향을 줄 수 있지만 다른 일부는 그렇지 않습니다. 첫 번째 방법은 장치를 검사하여 영향을 받는 구성 요소가 있는지 확인하는 것입니다. 경우에 따라 회로 기판에 미세한 구멍이 나타날 수 있습니다.

화학 물질 누출

PCB의 화학물질 누출은 많은 산업에서 문제가 될 수 있습니다. 미국은 1977년 PCB 생산을 금지했지만, 여전히 매우 낮은 수준으로 환경 내에서 발견되고 있습니다. 환경 순환은 주변 PCB의 주요 공급원이며 생태계를 통해 운반됩니다. 이러한 오염 물질은 낮은 수준이지만 인간과 환경에 심각한 영향을 미칠 수 있습니다.

PCB는 전자제품에 사용되는 것 외에도 1950년대부터 1970년대까지 학교 건물 건설에도 사용되었습니다. 많은 학교에서 PCB가 함유된 코크와 형광등을 사용했습니다. 이러한 제품의 문제점은 누출되어 다른 건축 자재와 토양을 오염시킨다는 것이었습니다. 이로 인해 광범위한 오염이 발생했고, 이것이 바로 사용이 금지된 이유입니다.

들어 올린 패드

납땜 중 과도한 열과 힘을 포함하여 여러 가지 원인으로 인해 패드가 들리는 현상이 발생합니다. 그 결과 납땜 조인트가 불만족스러워질 수 있습니다. 이러한 결함은 재납땜이 필요하며 단락 위험으로 이어질 수 있습니다. 패드가 들리는 다른 원인으로는 오염 물질 오염, 청소 불량 또는 플럭스 부족 등이 있습니다. 패드가 들리면 회로 기능 및 기판 외관에 영향을 줄 수 있습니다.

패드가 들리는 현상은 얇은 구리 층과 스루도금이 없는 기판에서 가장 자주 발생합니다. 리프팅의 근본 원인을 파악하는 것은 추가 손상을 방지하는 데 매우 중요합니다. 단면 회로 기판의 경우, 부적절한 웨이브 납땜으로 인해 문제가 발생하는 경우가 많습니다. PCB를 취급할 때 각별한 주의를 기울이고 부품을 다룰 때 과도한 힘을 가하지 않으면 리프트를 방지할 수 있습니다.

구성 요소 이동

부품 이동은 PCB 조립에서 발생하는 가장 일반적인 결함 중 하나입니다. 부품을 잘못 배치하는 등 여러 가지 요인으로 인해 발생할 수 있습니다. 예를 들어, 방향이 올바르지 않은 방식으로 배치된 부품이 떠서 부품이 다시 정렬될 수 있습니다.

부품 이동의 원인은 부품과 패드 형상이 일치하지 않기 때문인 경우도 있습니다. 이로 인해 부품이 가장 가까운 열 덩어리 쪽으로 이동하게 됩니다. 다른 원인으로는 구부러진 리드, 부적절하게 배치된 부품 또는 산화가 있습니다. 다행히도 부품 이동에 대한 해결책은 여러 가지가 있습니다. 예를 들어 올바른 리플로우 프로파일을 준수하고, 리플로우되지 않은 어셈블리 공정에서 움직임을 줄이고, 적극적인 플럭스를 사용하면 부품 이동을 최소화하는 데 도움이 될 수 있습니다.

납땜 볼 결함

솔더링 볼 결함은 SMT 조립 공정에서 흔히 발생합니다. 솔더 볼은 본질적으로 솔더 본체에서 분리되는 솔더 볼입니다. 이를 방지하려면 칩 마운터의 장착 압력을 정확한 설정으로 조정해야 합니다. 이렇게 하면 솔더 페이스트가 패드에서 압착되는 것을 방지하고 솔더 페이스트가 제대로 생성될 가능성을 높일 수 있습니다.

좋은 솔더 조인트는 깨끗하고 대칭이며 오목한 모양을 갖습니다. 반면에 불량 솔더 조인트는 크고 줄기가 길 수 있습니다. 또 다른 일반적인 결함은 조인트가 흐트러져 벗겨지거나 일그러지거나 고르지 않은 모양을 보이는 것입니다.

열화상 이미지

열화상 이미지는 품질 관리를 위한 강력한 도구로, PCB 및 부품 수리 속도를 높여줍니다. 열화상은 핫스팟을 식별하여 결함이 있는 부품이나 전력을 너무 많이 사용하는 영역을 찾아낼 수 있습니다. 이 정보는 설계자가 전력 소비를 줄이고 배터리 수명을 연장하는 데 도움이 될 수 있습니다. 또한 열화상을 통해 열 관리가 제대로 되지 않아 더 많은 냉각, 더 큰 방열판 또는 재설계가 필요한 영역을 감지할 수 있습니다.

PCB 결함에 대한 열화상 이미징은 설계자와 엔지니어가 결함의 원인을 파악하는 데에도 도움이 될 수 있습니다. 테스트 보드가 품질 관리 테스트를 통과하지 못하면 열화상 카메라로 문제를 파악할 수 있습니다. 또한 보드의 서로 다른 두 영역 사이의 온도 차이를 보여줌으로써 두 영역이 어떻게 다른지 밝혀낼 수 있습니다.

높은 열 전도성 PCB 소재가 방열 문제를 해결하는 방법

PCBs, also known as printed circuit boards, are layered structures made of copper foils sandwiched between glass-epoxy layers. These layers serve as a mechanical and electrical support for components. The high-conductivity copper foils serve as the conductive circuit in the PCB, while the glass-epoxy layer serves as the non-conductive substrate.

High thermal conductivity pcb material

Thermal conductivity is the ability of a material to transfer heat away from a device. The lower the thermal conductivity, the less efficient the device is. High thermal conductivity materials can eliminate the need for vias and produce a more uniform temperature distribution. This also reduces the risk of localized volumetric expansion, which can lead to hotspots near high-current components.

A typical PCB for a personal computer might consist of two copper planes and two outer trace layers. Its thickness is about 70 um and its thermal conductivity is 17.4 W/mK. The result is that the typical PCB is not an efficient heat conductor.

Copper coins

Copper coins are small pieces of copper embedded into the PCB. They are placed under the component that produces the most heat. Their high thermal conductivity allows them to transfer heat away from the hot component to a heat sink. They can be made in different shapes and sizes to fit the desired areas and can be metalized to ensure a tight connection.

Glass-epoxy

The problem of heat dissipation is becoming more important in electronics. Excess heat can lead to underperformance and early failure. Currently, heat dissipation options are limited, particularly in the extreme environments. One of the solutions to this problem is the use of high-temperature glass epoxy PCB material, or HDI-PCB. This material is able to solve this problem by having a thermal conductivity over two hundred times better than FR4 composite.

The glass epoxy resin has excellent heat and flame resistance. It has a high glass transition temperature and high thermal conductivity. It can serve as an insulating layer and a heat dissipation layer. It can be made by impregnation or coating. The thermal conductivity of glass epoxy PCB will improve the performance and stability of electronic components.

Metal core PCBs

Metal core PCB manufacturers have introduced new board substrates that can withstand high temperatures. This allows them to selectively apply thicker copper layers that have higher thermal conductivity. This type of PCB enables better heat dissipation and can be used for fine circuit patterns and high-density chip packaging.

In addition to offering higher thermal conductivity, metal PCBs are also dimensionally stable. Aluminum metal core PCBs have a 2.5-3% size change when heated, making them ideal for high-power applications. Their low thermal expansion properties also make them suitable for high switching power. The most commonly used metal used for a metal core PCB is aluminum, which is cheap and recyclable. Its high thermal conductivity allows for a fast cooling process.

Another problem associated with heat dissipation is the risk of excessive heat. The heat generated by heat-generating components must be removed from the board, otherwise the PCB will not perform at its best. Fortunately, there are now new options to solve this problem. High thermal conductivity metal core PCBs are a new kind of thermal solution that can overcome these problems.

FR4 substrates

PCBs are layered structures made of copper foils and glass-reinforced polymers. They support and connect electronic components. The copper creates a conductive circuit within the PCB, while the glass-epoxy layer acts as a nonconductive substrate.

High-power components are best placed near the center of the PCB, rather than on the edges. This is because heat accumulates near the edges and scatters out. Also, heat from high-power components should be placed far away from sensitive devices, and the heat must be channeled away through the PCB.

High thermal conductivity PCB material is the best solution for heat dissipation, allowing for rapid transfer of heat and preventing heat accumulation. High-tech PCBs use copper base, aluminum, or ceramic as the substrate material. This will solve the heat dissipation issues and make the PCBs more durable.

PCB 프로젝트를 주문하기 전에 알아야 할 사항

If you are going to order a PCB project, there are a few things that you should be aware of. For instance, you must double check your traces before ordering. In addition, you need to make sure that your BOM and drill file match. Moreover, you must choose the right material.

Double checking traces

When ordering PCBs from a PCB manufacturer, it is crucial to double-check the traces and spacing on your board. The thickness and width of the traces on your project will determine the amount of current that can flow through the circuit. You can use an online trace width calculator to find the ideal trace width. This will reduce the chances of connections breaking.

Checking your BOM

The first step in ordering PCB components is checking your BOM. It will help you avoid missing or incorrect component numbers. Using the BOM is also beneficial when it comes to sourcing parts. The description of the component will help the buyer and assembly house find a suitable replacement part. This will also help them confirm that the parts have the right MPN.

It is important to check your BOM before sending the PCB project to a manufacturer. This is because even a small mistake can cause problems during the PCB assembly process. You should also keep track of any changes made to the BOM and label them clearly. The most up-to-date version of the BOM is the one that you should use.

Once you have your BOM, you need to find out the cost of the component you’re ordering. It is important to know exactly what you’re going to be paying. The price of your components should match the BOM of your PCB project. If not, you may have to replace the components or even change the design.

Checking your drill file

You can easily check your drill file before ordering your PCB project from a PCB manufacturing company. However, there are some important things you must remember before placing an order. The first step is to make sure that the file is in the correct format. You can use a gerber file viewer to double check your file.

A drill file is a secondary file that explains where holes should be drilled on the PCB. This file must be sent along with the Gerber files. If your Drill file does not specify the locations or sizes of holes, your PCB order will fail the audit.

The drill file should also contain a tool list. It lists which tools are needed for each component hole. The tool list should be either embedded in the drill file or be sent as a separate text file. Failure to provide this tool list on the fabrication drawing will eliminate automated verifications and result in more errors when it comes to data entry.

Choosing the right materials

Choosing the right materials for your PCB project is essential. The physical properties of PCB materials can significantly affect the performance of the board. For example, a lower dielectric constant will mean thinner dielectrics and lower board thickness, while a higher dielectric constant will lead to higher losses. This information will help you narrow down your selection of PCB materials and find those that deliver the required performance.

Next, you should determine the number of routing layers on your PCB. For a simple PCB design, there may be only one or two layers, while a moderately complex design may need four to six layers. More complicated designs may require eight layers or more. The number of layers will directly affect the cost of your PCB project.

PCB 색상으로 표면 마감을 파악하는 방법

If you’re wondering how to know the surface finish of a PCB, you’re not alone. The color of a PCB can reveal its surface finish. You may also see a color designation called ENIG or Hard gold, Silver, or Light red. Regardless of what you see, you’ll want to make sure the PCB is plated to protect the surface.

ENIG

ENIG surface finish is one of the most popular finishes for PCBs. It is made by combining gold and nickel. The gold helps protect the nickel layer from oxidation, and nickel acts as a diffusion barrier. The gold layer has a low contact resistance and is usually a thin layer. The thickness of the gold layer should be consistent with the requirements of the circuit board. This surface finish helps extend the life of the circuit board. It also has excellent electrical performance and enhances electrical conduction between the PCB’s components.

ENIG surface finish has a higher cost but a high success rate. It is resistant to multiple thermal cycles and displays good solderability and wire bonding. It is composed of two metallic layers: a layer of nickel protects the base copper layer from corrosion, and a layer of gold acts as an anti-corrosion layer for the nickel. ENIG is suitable for devices that require high levels of solderability and tight tolerances. ENIG is also lead-free.

하드 골드

Hard gold is a costly PCB surface finish. It is a high-quality, durable finish that is often reserved for components that see a high level of wear and tear. Hard gold is usually applied to edge connectors. Its main use is to provide a durable surface for components that undergo frequent actuation, such as battery contacts or keyboard contacts.

Hard electrolytic gold is a gold plated layer over a nickel barrier coat. It is the most durable of the two and is typically applied to areas that are susceptible to wear and tear. However, this surface finish is very expensive and has a low solderability factor.

Silver

Depending on the PCB’s composition, it can be produced with different colors and finishes. The three most common colors for PCB surfaces are silver, gold, and light red. PCBs with a gold surface finish are usually the most expensive, while those with a silver finish are cheaper. The circuit on the PCB is primarily made of pure copper. Because copper oxidizes easily when exposed to air, it is very important to protect the outer layer of the PCB with a protective coating.

Silver surface finishes can be applied using two different techniques. The first technique is immersion, in which the board is immersed in a solution containing gold ions. The gold ions on the board react with the nickel and form a film that covers the surface. The thickness of the gold layer must be controlled so that the copper and nickel can remain solderable, and the copper is protected from oxygen molecules.

Light red

The surface finish of a PCB can be glossy, non-glossy, or light red. A non-glossy finish tends to have a more porous look, and a glossy finish tends to be reflective and hard shell-like. Green is the most popular PCB color, and it’s also one of the least expensive. It’s important to clean PCBs before using them to avoid oxidation.

Although solder mask color isn’t a direct reflection of PCB performance, some manufacturers use it as a design tool. The color is ideal for PCBs that require brilliant visibility and sharp contrasts. Red PCBs are also attractive when combined with silkscreens.

Electroless palladium

Using the electroless palladium surface finish on your PCBs prevents the formation of black pads on the board, and has many benefits, including excellent solderability and aluminum and silver wire bonding. This type of finish also has an extremely long shelf life. However, it is also more expensive than other finishes and requires a longer lead time.

The ENEPIG PCB surface finish process involves several steps, each of which requires careful monitoring. In the first step, copper is activated, followed by the deposition of electroless nickel and palladium. After that, the circuit board goes through a cleaning procedure, to remove oxidation residues and dust from the surface.

Lead-free HASL

If you’re looking for a new PCB, you may wonder how to tell lead-free HASL surface finishes from lead-based PCBs. While HASL has an attractive look, it’s not ideal for surface-mount components. This kind of finish is not flat, and larger components, like resistors, can’t align properly. Lead-free HASL, on the other hand, is flat, and does not use lead-based solder. Instead, it uses a copper-based solder that is RoHS compliant.

HASL offers high-quality solderability, and it can withstand multiple thermal cycles. It was once the industry standard, but the introduction of RoHS standards pushed it out of compliance. Nowadays, lead-free HASL is more acceptable in terms of environmental impact, as well as safety, and is a more efficient choice for electronic components. It also aligns more closely with the RoHS directive.