JEDEC PUBLICATION 95 PAGE 4.21-3/A 4.21-2 PACKAGE DESCRIPTION Internal Stacking Module(ISM)Land Grid Array Packages(LGA)with External Interconnect Terminals are plastic semiconductor packages with metalized package terminals or lands arranged in an array on the bottom surface of the package.These terminals are either flush with the bottom surface of the package or defined by solder mask. In addition to the land pad terminals arrayed on the bottom surface of the package,metalized fine pitch interconnect terminals(bond fingers)are located along the edges of the bottom surface of the package. These interconnect terminals can be on one side to all four sides of the package. The package can have a square or rectangular body as well as symmetric or asymmetric terminal patterns. The ISM LGA package is stacked within another BGA type package and then interconnect to base substrate is made by means of wire bonds attached to the external bond fingers of the ISM package per Figure 4.21-2.Therefore,the ISM LGA is embedded inside another package and the land pads are for testing purpose only(they have no 2 level or board level reliability impact).These land grid array pads can be eliminated altogether if testing of the bond finger terminals directly is implemented. Test Pads Terminals AW. Internal Stackina Module (ISM) Base Packaae ISM Stacked within Package FIGURE 4.21-2-ISM LGA Package Stacked within another PackageJEDEC PUBLICATION 95 PAGE 4.21-3/A 4.21-2 PACKAGE DESCRIPTION Internal Stacking Module (ISM) Land Grid Array Packages (LGA) with External Interconnect Terminals are plastic semiconductor packages with metalized package terminals or lands arranged in an array on the bottom surface of the package. These terminals are either flush with the bottom surface of the package or defined by solder mask. In addition to the land pad terminals arrayed on the bottom surface of the package, metalized fine pitch interconnect terminals (bond fingers) are located along the edges of the bottom surface of the package. These interconnect terminals can be on one side to all four sides of the package. The package can have a square or rectangular body as well as symmetric or asymmetric terminal patterns. The ISM LGA package is stacked within another BGA type package and then interconnect to base substrate is made by means of wire bonds attached to the external bond fingers of the ISM package per Figure 4.21-2. Therefore, the ISM LGA is embedded inside another package and the land pads are for testing purpose only (they have no 2nd level or board level reliability impact). These land grid array pads can be eliminated altogether if testing of the bond finger terminals directly is implemented. FIGURE 4.21-2 — ISM LGA Package Stacked within another Package Internal Stacking Module (ISM) ISM Stacked within Package Base Package Test Pads Terminals