Samsung Galaxy S7 Edge teardown

We are expecting many new devices inside the S7 and S7 Edge, so this blog will probably be spread over a few days. We will be deprocessing many of the chips and this takes time. As we get major sections of the phone deprocessed, we will update the story, so make sure you register to be notified every time we update. Immediately, it’s the display that grabs you. It is a stunningly brilliant AMOLED display with a resolution of 1440x2560.

Just as Apple had, in 2013, reversed the pixel shrink trend of the time by transitioning from a 1.4 to 1.5µm pixel pitch (iPhone 5 and 5s respectively), Samsung has similarly increased the pixel pitch of the Galaxy S7’s rear-facing camera. While the S6’s 16 MP camera featured 1.12µm pitch pixels, the S7’s rear-facing camera now uses 1.4µm generation pixels. Apple has since settled in on a 12 MP resolution (currently with a 1.22µm pixel pitch) for the iPhone 6s/6s Plus cameras. Samsung now meets Apple head-to-head at the 12MP resolution with its larger pixels. We’ll have to wait and see who wins the image quality battle; as of now, DxOMark Mobile does not have a score for the S7/S7 Edge. Currently tied for 1st place are Sony’s Xperia Z5 camera, which features a 23MP sensor with 1.12µm pitch pixels, and the 16MP Samsung Galaxy S6 Edge Plus camera. 

So what is new with the S7’s camera system? Dual pixel phase detection autofocus (PDAF) technology! We first saw this concept in use in 2013 in a much different imaging application: the Canon EOS 70D DSLR. Canon committed 80% of the 70D’s active pixel array to dual pixel CMOS AF functionality. A similar concept has now been adapted to the world of small-pixel mobile camera chips, where 100% of the 12MP active pixel array is committed to both sensing and providing data to the AF system.

What is impressive about the new dual pixel feature is the chip design team's ability to roll out this technology in a 1.4µm pixel generation (Canon’s DSLR system used 4.1 µm generation pixels). The results are stunning – the S7’s photos are of high quality, especially when viewed on its Quad HD display. We haven’t seen a claim for the S7’s AF system speed yet. As a reference point, Sony has reported a 0.03-second focus speed for its hybrid (contrast and phase detection) AF system in the Xperia Z5.  

We’ll be doing more thorough analysis of the dual pixel technology over the coming days and weeks, but our initial review of the 12MP camera module shows a camera module size of 12.1x12.1x5.4mm thick. We’ve been reading the web articles indicating a Sony IMX260 design win for the 12MP socket and we’re eagerly awaiting results from our lab to confirm. Based on the 'SONY' logo on the module’s flex cable, we believe the speculation to be true.

Our lab staff have removed the imaging chip from the 12MP camera module and have found a Sony back-illuminated (Exmor R) CMOS image sensor. We were expecting to find TSV arrays around the periphery of the active pixel array, corresponding to Sony’s stacked chip (Exmor RS) technology platform. Sony hasn’t publicly announced the IMX260, but based on what we’ve been reading, we assume that is the part number. It’s a bit of a surprise that the IMX260 isn’t an Exmor RS sensor, as we’ve been documenting a lot of Sony design wins based on its 1st and 2nd generation Exmor RS technology. It seems the full chip PDAF functionality, which requires dual readout from each pixel, was implemented with a multi-chip solution rather than a stacked (CIS + ISP) solution.

The Sony IMX260 die size, as measured from the die seals, is 6.69x5.55mm (37.1mm²). There are no conventional die identification markings in use on the die, consistent with back-illuminated (stacked/non-stacked) Sony CIS chips. We confirmed a pixel pitch of 1.4µm and a Bayer-patterned colour filter array. Work on this chip is ongoing and we will be reporting on this small-pixel event more extensively with a Device Essentials project and through our ChipSelect IS subscription service.

The front-facing camera module size is 8.0x7.2x5.0mm thick. It contains a back-illuminated Samsung die with S5K4E6XP die markings. The chip has a confirmed pixel pitch of 1.34µm and uses a Bayer-patterned colour filter array. On the flex tail coming off of the primary camera module, we find an STMicroelectronics K2G2IS gyroscope for image stabilization.

As soon as we got the cover off, we were able to start to ID some parts. For example, some of the the sensors and wireless chips are in plain view:

Once we got the motherboard out, we wanted to go straight for the application processor to look at the much-vaunted Qualcomm Snapdragon 820, but of course it is hidden under the Hynix LPDDR4 SDRAM in a package-on-package (PoP) format, as in almost all smartphones.

However, we are adept at popping off the top part of the PoP, so it didn’t take long to find the Snapdragon 820, now confirmed as the MSM8996. We’ll have to wait until the chip is off the motherboard and decapsulated before we can look at the die itself. We might have to wait to look at it, but if you’re interested in its capability, our friends over at AnandTech reviewed the performance of the 820 at the end of last year.

One thing we noticed is the large increase in the interconnecting solder bumps between the top and bottom parts of the PoP – earlier generations had only two rows connecting the two parts. This could be a result of the higher memory bandwidth being used these days, and/or the need to dissipate more heat from the higher performing processor, particularly the GPU.

Our expectation that Samsung adopts their own Touch Screen Controller (TSC) in their own phone was confirmed. The part number is S6SA552X. Chipworks first saw Samsung’s S6SMC41X TSC in a Chinese brand Doov L5Pro phone a few weeks ago. It is now our second time seeing Samsung’s TSC, but the first time in Samsung’s own phone.