Lei Feng network (search "Lei Feng Net" public concern) by: author of this article dragondevil, Microarray chief scientist, electronics and software designers. Lei Feng network exclusive article, reproduced please contact the authorization. Apple's release of iPhone 7 & plus's Home key to Under Glass's Touch ID 3.0 version did not materialize, and only the use of Taptic Engine to provide vibration feedback was eliminated. From the diagram provided at the conference, it can be seen that the space left after the 3.5mm headphone jack is removed is used to reinforce the microphone and insert the Taptic Engine. In principle, the Taptic Engine is as close as possible to the vibration feedback point, and it is best to keep close to it; but since the Home button is under the Lightning interface, it is the best possible solution to place near. Canceling the 3.5mm headphone jack is an adventure for Apple's most important experience, which shows how important it is to maintain an excellent physical key feel in the heart of the Apple design team. Such a change is obviously not logical for saving a potted chip, so this generation of Touch ID should be considered as an interim version, which may be called Touch ID 2.1 . When the experience of using virtual keys is market-proven, after updating the process to optimize the structure, the Touch ID's Sensor area can be improved and the fingerprint recognition security can be improved. So what are the problems that have prevented Apple from coming in one step? Of course, the packaging technology: The world's leading technology and patent analysis company, Chipworks of Canada, sponsored Touch ID 1.0 disassembly data. Touch ID 1.0 on the iPhone 5S and iPhone 6 (Plus), using Apple's patented Trench + wire bonding, steps at the edge of the die, and connects the Pad to the Trench via rewiring (RDL). , and then with the flexible circuit board (FPC) wire bonding (wire bonding) connection. Take a look at the part: Note that the edge of the circuit board is deformed downwards, which can pull the bond wire, causing it to fall off or break, and even cracking the colloids that protect the bond wire. This is the main reason for the low yield of Touch ID 1.0. As can be seen from the floor plan, in addition to low yield, the Trench also occupies a small area of ​​the chip, resulting in Touch ID 1.0's Sensor face is low, so that Apple can not cover the security of touch ID 1.0. China's top technology analysis organization, Shanghai Micro-Tech Industrial Research Institute, provided touch ID 2.0 disassembly information. The iPhone 6S (Plus) loaded Touch ID 1.0 uses Microarray's patented TSV-based structure. In order to better represent the entire packaging technology, the following uses a combination of X-ray images and schematics. As can be seen in the X-ray diagram, there is a bond wire at the bottom of the Die area. The schematic diagram is as follows: From the perspective of mechanical assembly, the sapphire cover, die, and flexible circuit board (FPC) are spatially stacked along the Z axis. Touch ID 1.0 destroys the integrity of the entire structure process due to the presence of a lateral connection process in the XY plane, resulting in a low yield. Using a TSV package to pull the Pad through the through-silicon via to the back of the Die and then connecting it from the back with the FPC solves this problem and improves the manufacturing yield. Let us review the stacking structure of the "Domestic Touch ID" published at the end of 2014. Apple only uses bond wires instead of ACFs to connect TSV packaged Dies and FPCs. This is "achievable within a limited number of attempts using known technologies in the industry," and is still within Microarray's patented technology. In addition to using the TSV process to eliminate the chip area occupied by the Trench, Apple also increased the wafer process from 180nm to 65nm, as shown in the cross-section below, to reduce the area occupied by the control circuit; This limitedly increases the Touch ID 2.0 Sensor area: And our "Homemade Touch ID" is the iPhone 7S's arrogance on the Sensor area from the beginning: Therefore, "too rich" may not be the designer's blessing, and may be the design flaw. Compared with Touch ID 2.0/2.1, the most important change in Touch ID 3.0 is the need to mount the chip directly on the glass. This is a TSV process route, but with a little difference: TSV process used in Touch ID 2.0, Die thickness is only 70um. Placing such a thin film on an uncut fine-grained sapphire wafer is still feasible. If it is to be mounted on the ink surface of a glass plate, it will have to be faced with a "broken and safe" outcome. Because the TSV package is mainly used for the memory stack technology, it has always been thin and beautiful, and the standard TSV is certainly not suitable for the fingerprint sensor. The fingerprint sensor requires the TSV package to have enough mechanical strength to handle the post-mounting process, so the thickness must be greatly increased. Since 2014, Microarray and partners have used the following method to increase the Die thickness of TSV packages: Seeing it, the solution is actually very simple: on the one hand, the upper limit of Die's thickness is increased by multiple levels of trenches, and on the other hand, the weak area is protected by a planar layout . If Apple wants to truly advance to Touch ID 3.0, even if it wants to return to the Jobs era, it must further align with Microarray and carefully study the industrial spirit of Microarray in its research, design, and manufacturing processes. Of course, there are some other minor issues in order to achieve the Under Glass-level Touch ID, such as the current low glass yield of local thinning polishing process. But compared with the problem of packaging technology as a major obstacle, this is not an issue. Moreover, for financially wealthy Apple companies, the cost of less than 10 USD added to cover the low yield of cover glass is not particularly a problem. I believe that after the preparation of Touch ID 2.1, Touch ID 3.0 can meet with you on the iPhone 7S on time. Ending Statement: I retracted the view that "Setlak was slightly behind the back of a tree because he started from scratch." Since iPhone 7 is not loaded with Touch ID 3.0, there is still a lot of time to launch the Under Glass Level Touch ID for iPhone 7S. Setlak is still a tribute figure, but this era belongs to us. Second-Hand Power Generator,Power Generator,Diesel Generator,Electric Generator Shaoxing AnFu Energy Equipment Co.Ltd , https://www.sxanfu.com
