Metallized Sidewall Die for Semiconductor Adhesion
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Solution Overview
Problem
The sintering process used in semiconductor package production leads to poor adhesion between sintered semiconductive glue and silicon dies, causing delamination and allowing impurities to reach the active side, which can short the die, and adhesive creep of the glue up the sides of the die also poses a risk.
Innovation Solution
A die with a metallized sidewall and backside, where a metal layer is applied to the backside and sidewall prior to adhesion to the die pad, forming a flange that extends from the active side to the backside, enhancing adhesion and acting as a barrier against adhesive creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is applied only to the wafer backside before separation, then the adhesion between sintered glue and die backside is improved, but the sidewalls remain bare causing poor adhesion and delamination
Solution Approach 1:
The patent extends the metal layer coverage from the traditional two-dimensional backside surface to include the three-dimensional sidewalls of the die. This dimensional extension ensures that all surfaces in contact with the sintered glue are metallized, eliminating bare silicon sidewalls that cause delamination and providing uniform adhesion throughout the die perimeter.
Solution Approach 2:
The metal layer is applied to the wafer backside and sidewalls before the wafer is separated into individual dies. This preliminary metallization ensures that when the sintering process occurs later, the glue immediately contacts a metallized surface, preventing delamination from the outset and eliminating the need for post-separation metallization steps.
2Reliability
If the sintering process is used to create intermetallic bond, then electrical and thermal characteristics are improved, but adhesive creep up the die sides occurs allowing glue to reach active side
Solution Approach 1:
The metallized sidewalls act as an intermediary barrier between the sintered glue and the bare silicon sidewalls. The metal layer modifies the surface properties to prevent adhesive creep from occurring on the silicon surface, while still allowing the sintering process to create the desired intermetallic bond for improved electrical and thermal characteristics.
3Productivity
If wafer is cut through scribe lines to separate dies, then individual dies are formed, but kerf removal exposes bare sidewalls without metal coverage
Solution Approach 1:
The metal layer is deposited on the wafer backside and sidewalls before the cutting process that separates individual dies. This preliminary metallization ensures that when the blade removes the kerf material and exposes the sidewalls, the sidewalls are already covered with metal, maintaining adhesion reliability without requiring additional post-cutting metallization steps.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The metallized sidewall increases adhesion between the sintered glue and the die, preventing delamination and impurity ingress, while the flange barrier limits adhesive creep, ensuring the die's electrical functionality and reliability.
Implementation Method 1
a metal layer is formed on the die backside and a portion of the die sidewall prior to the adhesion to the die pad
Implementation Method 2
the use of a sintering process to create an intermetallic bond between a semiconductor glue and the die pad
Data Source
AI summary
The present disclosure is directed to a die having a metallized sidewall and methods of manufacturing the same. A contiguous metal layer is applied to each edge of a backside of a wafer. The wafer is cut at a base of a plurality of channels formed in the backside to create individual die each having a flange that is part of a sidewall of the die and includes a portion that is covered by the metal layer. When an individual die is coupled to a die pad, a semiconductive glue bonds the metal layer on the sidewall and a backside of the die to the die pad, which decreases the risk of delamination along the sides of the die. The flange also prevents the glue from contacting the active side of the die by acting as a barrier against adhesive creep of the glue up the sidewall of the die.