Archive for the ‘HDI PCB’ Category

How to Test for an Open Short Circuit on a PCB?

Tuesday, May 18th, 2021

Every printed circuit board need to do full test before ship to our customer. but you may have doubt, the PCB was made according to the original Gerber file, why finish the PCB production process, why the short Circuit will occur on a FR4 circuit board?

A short circuit may also occur during reflow soldering. the solder paste may accidentally connect two pins that are very close to each other. In some cases, errors can occur during the PCB design process because the wiring between different networks accidentally connects.

We believe every PCB manufacture have their own test method to do short circuit, but today I would like share how Best Technology to Check for Short Circuits in a Printed circuit board.

Here are some important steps:

Step 1 Visual inspection

The first step for locating short circuits on PCB is to carefully look at the entire surface of the PCB. Best Technology QC guys use a magnifying glass or low magnification microscope during the circuit board examination. We check the whole board surface to see if there are some traces break off. Any cracks or blobs of solder should get careful attention. Check all your vias. If you specified unplated vias, make sure that’s the case on the board. Poorly plated vias can create a short circuit between layers and leave you with everything tied to ground, VCC, or both.

visual inspection

All the testing work will carry out according to IPC 6012 class 2.

Step 2 Use a Digital Multimeter to find out where is the problem

To test a circuit board for a short circuit, you need to check the resistance between different points in the circuit. If visual inspection doesn’t reveal any clues as to the location or cause of the short circuit, grab a multimeter and try to track down the physical location on the printed circuit board. The multimeter approach gets mixed reviews in most electronics forums, but tracing your test points can help you figure out what isn’t the problem.

Step 3 use Probe flying Tester &E-tester

As long as you are in Printed Circuit board field, you are definitely known Probe flying test and E-Teter.

Flying probe test systems require no test fixture, it can serve both prototype and small production, providing maximum flexibility for PCB manufacturers and this job can complete in a short time.

probe flying test
probe flying test-1

But when your circuit board become to volume, you will need to open a test tooling/test fixture to test the Printed Circuit board to test the open short circuit.

E-tester

In my next blog in June, I will introduce Probe flying test to you in more detail.

If you have any question about printed circuit board, you are welcome to contact Best Technology.

It is our great pleasure to communicate with you for any issue for printed circuit boards.

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What is Blind Via and Buried Via for Printed Circuit Board?

Thursday, April 15th, 2021

In the Printed Circuit Board industry, believe that you are familiar with blind via and buried via. What is blind via and buried via for PCB? And do you know is the Blind via or Buried Via have special application in your Printed Circuit Board?

In order to know more, we would like to share more information with you today.

Best Technology is an experienced FR4 PCB manufacturer in China since year 2006, with more than 15 years design and fabricate experience for PCB, Best Technology accumulated more than 1000 customers from all over the world.

Before start, we need to know what kinds of hole for FR4 Circuit Board, Via, Blind Via and Buried Via.

What is a Via?

Vias are the copper-plated holes in the PCB that allows the layers to layer connection. The standard via is called a through-hole via, but there are several disadvantages to using through-hole vias in Surface Mount Technology (SMT). For this reason, we often use a blind via or buried via instead. A blind or buried via can be processed in a wide range of different measures, including plugged copper mask via, a plugged solder mask via, plated via or staggered via.

Via
staggered via

What is Blind Via?

The via connects the external layer to one or more inner layers of the PCB and is responsible for the interconnection between that top layer and the inner layers.

Blind Via

What is Buried Via?

For a buried via, is the inner HOLE, between both sides in the board up and down inside the layer after pressing is cannot see. So, it doesn’t have to take up the outer area.

Buried Via

Blind and buried vias are particularly advantageous in HDI board because they optimize the density of the boards without increasing board size or the number of board layers you require. They are most commonly used in high-density PCB designs like, or in FPGA and custom chip packaging.Here is the photo which Best Technology took from our production line to make HDI Printed Circuit Board for our USA customer.

HDI board under production
HDI process

Best Technology is a very professional manufacturer in printed circuit board and HDI Board. If you are interesting to know more information of us, come to contact us and we are looking forward to discuss with you more for Printed Circuit Board.

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High-TG FR4 Printed Circuit Board

Thursday, December 31st, 2020

If you work in Printed Circuit Board industry, you may know a normal PCB FR4-Tg is 130-140 degrees, the medium Tg is greater than 150-160 degrees, and High-TG FR4 Printed Circuit Board is greater than 170 degrees.
And what is a High-TG FR4 Printed Circuit Board? High-TG PCB is another name for a high-temperature FR4 PCB, it means the printed wiring boards designed to endure for extremely high-temperature. A Printed Circuit Board is defined as high-TG FR4 PCB if its glass transition temperature (TG) is higher than 170 degrees Celsius. High-TG FR4 will have better mechanical and chemical resistance to heat and moisture than standard FR4. The higher the TG value, the better the temperature resistance of the material, so High-TG FR4 is more and more popular particularly working in high power industry.
Best Technology can provide many different High-TG FR4 material for Rigid Circuit board, Typical High-TG FR4 PCB material including: ITEQ-IT-180A, ISOLA 370HR, ShengYi S1000-2 and etc.

Part of the inventory of raw material-1
Part of the inventory of raw material-2
Part of the inventory of raw material-3

From the following PCB picture, you can see the normal TG130 FR4 PCB substrate is not only softening, deformation, melting, as well as other phenomenon working under high temperatures, but also there is a sharp decline in electrical properties, which will effect on product life.

Solder mask blistering-1
、Solder mask blistering-2

If your FR4 Printed Circuit Board or PCBA board appear to above problems, then you should consider to use a High-TG FR4 Rigid Circuit Board. it may be catching your interest willing to understand a little bit more about High-TG FR4 printed circuit boards. Because High Tg Rigid Circuit board have a better stability at high temperatures, the substrate provides better heat resistance, mechanical and chemical stability for the circuit board.

BPM20396)

Properties/ Applications of high Tg PCB
With the rapid development of electronics industry, High-TG FR4 PCB is widely used in Uninterrupted Power Supply, precise instrument as well as industry. High-TG FR4 PCB material probably designed for the high functionality, high multi-layer development high-density circuit; higher heat resistance and high-density surface mounting technology (SMT). So, the demand on High-TG FR4 PCB material become more widely used PCB manufacturing.
What’s more, High TG material is also popular in LED lighting industry, because heat dissipation of LED is higher than normal electronic components, but same structure of FR-4 board is much cheaper than metal core PCB, such as aluminum PCB.
High-TG FR4 PCB materials have the following properties:
 Resistance to high temperatures
 Long delamination durability (aging of materials to consider for safety reasons)
 Low thermal expansion
Excellent PTH reliability
Good mechanical properties
High temperature durability
High value of thermal stress resistance
high temperature durability
long delamination durability
Low Z axis expansion (CTE)

BPM19308

Advantages of High-TG FR4 PCB
Higher stability: it will automatically improve the heat resistance, chemical resistance, moisture resistance, as well as stability of the device if increasing the TG of a printed circuit board substrate.
Bear high power density designs: high TG PCB will be a good solution for heat management if the device has high power density with quite high heat generation rate.
It can achieve with using a larger printed circuit board to change the design and power requirements of a device when reducing the heat generation of ordinary board, what’s more, it also can use the high TG PCB.
Ideal for multilayer & HDI PCBs: there will lead to high levels of heat dissipation because multilayer & HDI PCBs are more compact and have dense circuits. So high TG PCBs are often used for the multilayer & HDI PCBs so that it can make sure reliability in Printed circuit board fabrication.

BPM20005 TOP
BPM20005 BOT

 If your applications are in any danger of subjecting your PCBs to extreme temperatures or the PCB is required to be RoHS Compliant, it will be in your best interest to look into high-TG FR4 PCBs.
Come to contact Best Technology Co., Limited. for High-TG PCB assistance. we can help you determine if you need high-temperature printed circuit boards and direct you to which specific boards are likely to be useful for your design and application. If you are transitioning to RoHS or just need more information about the High TG laminates, just give us a call and we’ll be happy to accommodate you. contact us online right now.

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What is an HDI FR4 PCB?

Wednesday, September 16th, 2020

HDI abbreviation means High Density Interconnect. HDI PCBs have extremely density trace spaces and lines, micro vias under 0.25mm(10mil), smaller pads and higher connection pad density. See the photo of HDI board laser drill& prepreg thickness ratio.

It is very helpful in enhancing electrical performance and HDI PCB use for high-end products and HDI PCB is regularly used in 4G network communications, medical, Military and Aerospace. See the HDI board which Best Tech made for customers.

HDI PCB is the better option for high-layer count and costly laminated boards. Due to the increasing complexity of design structures laminate, the Blind vias and Buried vias are increasingly used in high-density circuit boards (HDI PCB board). Best Tech always improved manufacture capability for HDI, following production capability of the comparison for 2020 and the capability which Best Tech want to achieve at year 2021.

Following is the advantages to use an HDI PCB

The common reason for using HDI technology is a significant increase in packaging density. In addition, overall space requirements are reduced will result in smaller board sizes and fewer layers. 

1.Denser trace

2.More stable performance

3.Reduce interference inductance and capacitance effects

4.Improve signal integrity in high-speed design

5. Reduce frequent relocation of components

What’s mean for a blind via hole?

It is a hole runs from an outer layer, but not through the entire PCB. These holes can be drilled mechanically or using laser technology.

And what’s mean for a buried via hole?

This is a hole that runs between one or more inner layers. They are normally mechanically drilled.

By the way, we would like to make some explain for the through via hole, see attached photo to know the detail.

Do you want to know the different types for HDI PCB boards?

The following photos mainly shows the different laminate structures available from Best Tech for HDI PCB for prototype and mass production.

What is the minimum pad size of hole on the outer and inner layer?

This is different from manufacturer to manufacturer, but in general you can say that the majority of manufacturers can produce them as follows:
A = 0.10 mm
B = 0.15 mm
C = 0.20 mm

Finally, here is an 8L HDI FR4 PCB which we made for our customer at June. See the stack up information.

Surface finish: ENIG(2u”)

Features

1. 3+(2)+3  HDI FR4 PCB board

2. L1 L2、L2 L3、 L3 L4、 L5 L6、 L6 L7、 L7 L8 laser blind hole, micro via size:0.15mm

3. L3、L6 mechanical blind hole, hole size:0.25mm, through hole:0.3mm

4. minimum trace width and space is 3/3mil

5. Finished board thickness: 1.3±10%

6. following is the stack up information

For more information for HDI PCB, welcome to send any query to Best Tech for advice.

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