Manufacture and Characterization of a Novel Flip-Chip Package Z-Interconnect Stack-up with RF Structures

Publisher: Endicott Interconnect

Format: PDF
Date: 2008-01-18

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Overview:
Emphasizing on the need for multi-GHz RF structures for multi chip packages to meet their performance targets, this paper demonstrates a new flip-chip package test vehicle (TV) that uses Z-axis interconnection (z-interconnect) building blocks to make RF structures. The report elucidates the advantages of Z-interconnect stack-up and lists the main features that an RF flip-chip package requires. Z-interconnection construction is described with the help of diagrams of a series of building blocks called cores, composite stack-up, and a snapshot of the basic test vehicle design. Composite lamination process is explained and an illustration of sixteen-layer z-interconnect composite is presented. Observations regarding the formation of conduction path are studied with the help of SEM micrograph of conductive adhesive with nano and micro particles. The report includes Time-Domain Reflectometry (TDR) plot showing the impedance measured along the transmission lines.

TABLE OF CONTENTS
1.	Introduction	1
2.	Z-Interconnect Construction	1
3.	Test Vehicle Design	3
4.	Composite Lamination	4
5.	Results and Discussion	4
6.	Conclusions	6
7.	References	6
8.	Figures
8.1.	Figure 1 Versatile, Arbitrary Stack-Up	2
8.2.	Figure 2 : Fabrication of Joining and Signal Cores	2
8.2.1.	(A) Etch 2P core	2
8.2.2.	(B) Drill Laminated 2P Core	2
8.2.3.	(C) Paste Fill Drilled 2P Core	2
8.2.4.	(D) Etch Laminated 2P Core	2
8.2.5.	(E) Drill and Plate Laminated 2P Core	2
3.	Figure3: Z-Interconnect Composite Stack-Up	3
8.4.	Figure 4: Buried and Blind Vias in Core	3
8.5.	Figure 5: Embedded Capacitance Layer and Embedded Discrete Caps and Resistors	3
8.6.	Figure 6: Mixed Dielectric Stack-Up	3
8.7.	Figure 7: Snapshot of Test Vehicle Design	4
8.8.	Figure 8: Sixteen-Layer Z-Interconnect Composite	4
8.9.	Figure 9: SEM Micrographs Conductive Adhesive with Nano and Micro Particles	4
8.10.	Figure 10: Cross-section of Conductive Paste Connection in the Test Vehicle	5
8.11.	Figure 11: Test Results with Stripline	5
8.11.1.	(A) Designed configuration	5
8.11.2.	(B) Deep Stripline (270µm) Insertion Loss	5
8.11.3.	(C) Deep Stripline (270µm) Return Loss	5
8.11.4.	(D) Shallow Stripline (48µm) Insertion Loss	5
8.11.5.	(E) Shallow Stripline (48µm) Return Loss	5
8.12.	Figure 12	6
8.12.1.	(A) TDR Plot	6
8.12.2.	(B) Insertion Loss dB/inch of Stripline in Organic vs. Ceramic Dielectric	6