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Method for DI water-immersed back-grinding process

IP.com Disclosure Number: IPCOM000125765D
Publication Date: 2005-Jun-16
Document File: 3 page(s) / 355K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for deionized (DI) water-immersed back-grinding process. Benefits include improved functionality, improved performance, reliability, and improved yield.

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Method for DI water-immersed back-grinding process

Disclosed is a method for deionized (DI) water-immersed back-grinding process. Benefits include improved functionality, improved performance, reliability, and improved yield.

Background

              Dice become prone to cracking when ground to a thickness below 3 mils. Warpage is reduced due to tape shrinkage after grinding because less heat is induced by the friction of the grinding wheel on the backside of the silicon wafer.

              Conventionally, the problem is solved by limiting the wafer thinning process boundary to 3 mils.

              Water is used as a lubricant during the grinding process. A single nozzle with a 0.5-inch diameter is directed towards the grinding wheel. The nozzle is pointed directly at the center of the point of contact between the grinding-wheel and the wafer radial length. Optimum lubrication is dependent on a stable DI water pressure and flow rate (see Figure 1).

 

      Friction from the grinding process results in damage to the die backside.

              When water is used as a lubricant, an unstable water supply causes damage to wafers and the machine chuck table. Heat is induced that may cause unstable wafer thickness, laminating tape shrinkage, and die warpage.

 

Description

              The disclosed method is a submerged grinding process for wafer-thinning to thicknesses less than 3 mils. The method results in less friction, controlled temperature, and a more consistent final thickness.

              The key elemen...