Semiconductor devices are required to have higher performance and lower power consumption and to be produced at lower cost. To meet these requirements, many techniques such as System in Package (SiP) are developed (refer to, for example, “Nikkei Electronics” pp. 81-92 in Oct. 10, 2005 issue, published by Nikkei Business Publications, Inc.) In this non-patent document, techniques for interconnecting plural chips which are sealed in a single package are described. One example disclosed in this document is such that, on one surface of an interposer for, for example, a memory card, four chips (ND type flash memories) are stacked and electrical connections between each chip and the interposer are provided by wires (wire bonding). Another example disclosed in the same document is such that, on one surface of an interposer for a memory card, eight chips (ND type flash memories) are stacked and electrical connections between chips and a chip and the interposer are provided by Si through-hole electrodes.
In the same document, further, a method for manufacturing an image pickup element is disclosed. Disclosed in this document are section views by process step to illustrate a method for manufacturing a conventional image pickup element by utilizing wire bonding and section view by process step to illustrate a method for manufacturing an image pickup element by utilizing Si through-hole electrodes.
In the former section views by process step, the section views are described in which, after chips with their sensor surfaces facing up are joined to the top surface of a supporting substrate, the chips and the supporting substrate are connected by wires and then a protective glass is joined to the sensor surfaces.
In the latter method for manufacturing an image pickup element, the following process steps are disclosed. First, a supporting material for protecting sensors is attached to a wafer. Then, the wafer is thinned. Next, Si through-hole electrodes are formed and a rewiring/backside protection layer is formed on the exposed surface of the wafer. Then, the supporting material is removed and a protective glass is attached to the sensor surface of the wafer. Next, external terminals are installed. Finally, the wafer with the protective glass is cut into individual chips. In this way, the image pickup element is manufactured.