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Molded Interconnect Substrate with Tin Pillar for FlipChip PoPb

IP.com Disclosure Number: IPCOM000248048D
Publication Date: 2016-Oct-21
Document File: 8 page(s) / 915K

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 36% of the total text.

Page 01 of 8

Molded Interconnect Substrate with Tin Pillar for FlipChip PoPb

Background

There are PoP package structures using the Cu core solder balls and Cu pillars on the laminate substrate to support the interposer for package interconnection. The conventional PoP structures can be depicted as follows: (a) Flip chip PoP with laser ablation in Figure 1A, employed the laser groove technology to make openings through the molded package, wherein the copper core solder balls are placed in stack to form a support pillar that enable interconnection with interposer (b) Flip chip PoP with core solder ball in Figure 1B, is using the Cu core solder balls mounted on substrate as support pillar, which embedded after molding with the solder ball exposure for interpose interconnection (c) Flip chip PoP Cu Post in Figure 1C, is having the embedded copper pillars with top exposure on the typical substrate for solder ball interconnection.

Conventional PoP Structures

Figure 1A: Flip chip PoP with laser ablation

The openings are created into mold surface of package using the laser groove technology, and have the copper core solder balls to be stacked in as pillar support for connection with the laminate interposer.

Figure 1B: Flip Chip PoP with Core Solder Ball

The interposer is overlaid and connected with the embedded core copper solder balls.

Figure 1C: Flip Chip PoP Cu Post

The interposer is connected with the embedded pillars by means of solder ball attach.


Page 02 of 8

Molded Interconnect Substrate with Tin Pillar for FlipChip PoPb

This invention renders the creation of Molded Interconnect Substrate (MIS) with tin pillars. The pillar is the infilled tin metal in the partial-etch ring hollow on the carrier. The standard MIS substrate process flow will then be carried out, thereby producing a MIS substrate with tin pillars. It can be fabricated as in single metal or dual metal layers shown in respective Figure 2A and 2B for the flip chip and BGA assembly. The packages using the MIS substrate with tin pillars enabled the package stacking interconnection to constitute a POP structure.

Figure 2A: MIS single metal layer with tin pillars

Figure 2B: MIS dual metal layers with tin pillars

Description

The process flow of producing MIS single metal layer with tin pillars is started with creating circular holes on the carrier. The holes are uniform in diameter, relatively at a defined depth into the carrier which can be achieved by means of drilling, engraving or etching process. Optional through-hole of needle size coincided in paralel to the center of respective circular hole, which is conceived as air vent can be included as shown in Figure 3A. It is intended to curb air trap or void, and aids to unobstructed the airway passage for tin filling by means of solder paste printing or by solder ball placement in mass and then reflow. Figure 3B shows the tin inside each circular hole full to the brim after the solder reflow with surface treatment on carrier. The condu...