How to Avoid Patent Infringement in PCB Reverse Engineering PCB Layout

PCB reverse engineering is often associated with hackers, piracy, and theft for those who are not familiar with this project. But it's not entirely true. With the prevalence of patent wars, reverse engineering is not only used by many companies to protect their own patents, ensure that competitors cannot illegally use these patents, but also to protect themselves from infringing on their competitors' patents.

For the semiconductor industry, reverse engineering has always been the main axis of research and development design, which can assist IC design in conducting comprehensive analysis of the cost, labor, manpower, and technology required for developing new products. It can also be used for patent avoidance by analyzing patent maps and databases for patented circuits, in order to understand market trends and seize business opportunities.

For the analysis of reverse competitiveness of chips, we have discussed how to use a delayer technique to observe the circuit layout of each layer in the die for advanced process chips at the nanoscale; I have also shared how to scan and take photos on a large scale, and perspective the circuits of nanoscale chips (read more: How to use SEM full field imaging technology, reverse perspective nanoscale processes, and avoid infringement?). We will share three major cases, taking you from reverse engineering in the nanoscale world, back to BGA packaging, and even large-scale layout extraction technology at the PCB level.

Case 1: Through 3D X-Ray, there is no need to remove layers and complete the routing of each layer

This case is to understand the structure of each layer of BGA packaging. In this case, destructive acid etching cannot be used to remove the packaging. Once removed, the BGA packaging will be damaged. What should we do then? At this point, we can use an ultra high resolution 3D X-Ray microscope (referred to as 3D X-Ray), which is a non-destructive X-ray perspective technology, combined with an optical objective to increase magnification for analysis. The analysis method is to fix the test sample and rotate it 360 °, collecting 2D penetration images from different angles during this process, and then use computer operations to reconstruct the physical image of the test sample.

Especially, we can conduct layer by layer analysis on the tested sample to reveal the internal structure one by one, as shown in Figure 1. For the BGA tested sample, the wiring from the packaging to each layer inside the chip can be proposed one by one; Through image presentation, local line width/spacing, via size, and thickness of each layer structure can also be measured.

• 

  Figure 1: This is the image of each layer of BGA substrate scanned using high-order 3D X-ray

Case 2: By grinding and removing layers and taking photos with OM, the wiring image becomes clearer

For packaging materials such as SiP and small BGA, as long as the size of the test sample is below 5mm * 5mm and the observed Layer layer is within three layers, 3D X-ray reverse engineering can be chosen without damaging the sample; But if your test sample is a large BGA complex package with a size exceeding 5mm * 5mm, it is recommended by the failure analysis laboratory to perform back grinding to remove layers, and then take photos through a digital optical microscope (OM) to present the wiring appearance more clearly (Figure 2).

• 

  Figure 2: This is the image of each layer of BGA substrate taken through general grinding and OM photography

Case 3: Die and Substrate Circuit Layout Analysis, Can Have Both Fish and Bear's Paw

This case not only hopes to reverse engineer the routing of the substrate layer (Substrate) in BGA, but also hopes to know the layout analysis of the die metal layer (Metal) inside the package, and even to overlay and perspective the layout analysis of Substrate and Metal. Can we first use 3D X-ray to capture Substrate Layer 1-3 layers, then grind and remove the layers of Substrate, and shoot the Metal layer through OM to obtain two images, and then perform the overlay and perspective of Substrate Layer 1-3+Metal layers?

The answer is not possible! Due to the fact that 3D X-ray and OM are two different types of image presentation, it is absolutely impossible to overlay for perspective, and grinding is done from the tin ball surface instead of taking photos from the back of the crystal or the front end of the IC. The order of taking photos and overlaying will be mirror oriented, which is difficult to interpret (left of Figure 3).

What should we do then? Yite Failure Analysis Laboratory exclusively develops special reverse engineering techniques to quickly assist you in obtaining the perspective images of Substrate Layer 1-3 and Metal layer stacks. Through Yite's exclusive viewing software, you can flip the photos of each layer and stack them from top to bottom (Figure 3, right), making it convenient for users to track the lines and know the connection relationships of each layer (Figure 4).

Figure 3 (left): Grinding from the surface of the tin ball instead of taking photos from the front end of the IC. The order of taking photos and overlaying them will be mirror oriented, which is difficult to interpret; Figure 3 (right): Through the exclusive viewing software provided by Yite, the photos of each layer can be flipped greatly and stacked from top to bottom.

Figure 4: Through the exclusive image viewing software provided by Yite, users can easily track and learn about the connection relationships of each layer

HUANYU PCB has more than experienced and skilled senior engineers, Successfully reverse cloned various products, involving multiple fields such as smart homes, computers, rail transit, beauty instruments, office equipment, medical electronic devices, automotive electronics, high-speed communication, security monitoring, UPS power supply,new energy, industrial control, home appliances, game consoles, etc. Our technology and services have been unanimously recognized by the market, and we look forward to working with you.