TSG-T3 (USIM) meeting #2		Tdoc T3-99045
Munich 17th - 19th February, 1999

ETSI SMG9 Generics #4					Tdoc SMG9 Generics 9g99-012
Munich,
15-16 February 1999

				Proposal for third size UICC

Source: STMicroelectronics

This document proposes some alternative packaging possibilities as a basis for discussion of the smaller third size UICC.  This proposal will not cover the possibilities for plastic shrink or  umodule shrink of the existing plug-in format , but will propose a CSP (chip scale/size package) for minimum package size.
The parameters taken into consideration for this proposal are that the SIM may be
i) removable or  ii) fixed and iii) have the possibility for Marking on package.

As silicon chip size decreases with technology shrink and higher integration, the packaging technology follows this same trend. And instead of traditional packages such as DILS - these are being replaced with Surface Mount Devices, which allows contact pitch of 0.8mm and Ball size of 0.3mm. 
The Chip Scale/size Package is an example of a surface mount device. There are several variants of  this technology:  Medium pin count such as  BGA (Ball grid array) [ Flip chip BGA, LBGA, mBGA] or Low pin count such as SHELLCASE or BCC (bump chip carrier)
The difference between the low pin count options is that BCC  is a packaging technology carried out at chip level, while SHELLCASE  is processed at wafer level.

The Advantages of CSP with respect to more traditional SMD packages are
	a) Size, the silicon chip is 80% of package.
	b) Thickness ;  <0.5mm is possible
	c) Package solution at wafer level is possible
	d) The size can be adapted on demand , but contacts can have a fixed position
	e) Testability & Reliability of package is standardized
	f) The chip can be directly soldered onto printed board with ISO contact printing 
			( for the non-removeable option)
	g) Laser printing is possible
	h) CSP  is based on available market standards and are available in the public domain. 
		
One possible restriction is related to the removal  option, since a sub-assembly system (i.e. PCB) is required. However in this case some innovative ideas can be used to minimize the PCB (printer circuit board) and so optimize the final size. In addition,  CSP sockets already exist on the market for the removable option.