Here is how the application processors (AP) are packaged using Package-on-Package (PoP) technology

I have pleasure to recall that, located under the DRAM chip on the main board, the application processors (AP) are packaged using Package-on-Package (PoP) technology. The Apple A10 can be found in the iPhone 7 series. The HiSilicon Kirin 955 can be found in the Huawei P9 and the Samsung Exynos 8 as the Qualcomm Snapdragon 820 can be found in the Samsung Galaxy S7 series depending on the world version (US and Asia for the Snapdragon and International for the Exynos).