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Method of Die to Substrate Bonding

IP.com Disclosure Number: IPCOM000197274D
Publication Date: 2010-Jun-30
Document File: 6 page(s) / 191K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention involves connecting a semiconductor die's bonding pads to a substrate without the implementation of C4 bumping on either wafer or substrate. Using a specially designed die collet, pre-solder filled substrate and vacuum technology, the solder from the substrate is easily adhered to the die pads through a sequence of processes.

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Method of Die to Substrate Bonding
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Abstract

The invention involves connecting a semiconductor die’s bonding pads to a substrate without the implementation of C4 bumping on either wafer or substrate.  Using a specially designed die collet, pre-solder filled substrate and vacuum technology, the solder from the substrate is easily adhered to the die pads through a sequence of processes.

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1.0  Problem Description

C4 bumping on wafers are costly. Moreover, electroless C4 bumping on substrate are also costly to manufacture. The planarity of the bumps on wafer/substrate has to be controlled to ensure integrity of connection. Dies with C4 bumping are at full wafer thickness. This is due to the fact that bump wafers cannot be back-grinded.

2.0 Proposed Solution

The idea involves a die without pre-C4 bumping, pre-filled solder in a substrate and a specially designed collet to place the die on the substrate. The substrate is pre-filled with solder (screen filled) with a portion not completely filled. The solder position points matches directly with the die’s pad position.  The collect has dual function which is used to pickup the die and also create a vacuum environment surrounding the die and substrate. The process steps are described in the section 2.2.

2.1 Major Components.  (Refer to Figure 1)

2.1.1. Specially designed collet with dual vacuum system.

2.1.2. High Temp Seal mounted to the base of the collet.

2.1.3 Via-holes in substrate

2.1.4. Pre-filled solder in substrate’s Via-holes

Figure 1.  Major components of the solution for a BGA package

2.2 Working of Solution.

2.2.1 Step 1. The Upward looking camera registers the fiducial locatio...