Semiconductor Device Light Shield Slit Bubble Prevention
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Solution Overview
Problem
In CSP-type semiconductor devices with light receiving elements, the formation of bubbles in the adhesive layer within recess portions of the light receiving element due to high-speed rotation during attachment can lead to reduced light sensitivity and reliability issues, as the passivation silicon nitride film absorbs light and the recess portions are filled with epoxy resin.
Innovation Solution
A semiconductor device design featuring a recess portion on the light receiving element with an opening slit in the light shield film extending from the recess portion, allowing bubbles to be discharged and reducing stress in the adhesive layer, thereby preventing cracks and ensuring reliable attachment of the supporting substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed rotation is used to attach the supporting substrate with epoxy resin, then attachment speed and productivity are improved, but bubbles are trapped in the recess portion of the light receiving element, reducing light sensitivity and reliability
Solution Approach 1:
The light shield film is segmented by forming an opening slit that divides it into multiple portions. This segmentation allows the adhesive layer to be continuously supplied through the slit to the recess portion, preventing bubble entrapment while maintaining high-speed rotation attachment processes.
Solution Approach 2:
The opening slit in the light shield film acts as an intermediary channel that allows the adhesive material to reach the recess portion of the light receiving element. This mediator enables continuous adhesive supply during high-speed rotation, preventing bubble formation while maintaining attachment productivity.
2Illumination intensity
If the passivation silicon nitride film is removed from the light receiving element region, then light sensitivity is improved, but the structural integrity and protection of the light receiving element are reduced
Solution Approach 1:
The light shield film is removed only in the specific region of the recess portion where light needs to reach the light receiving element, while the rest of the film remains intact to provide structural protection. This local modification allows light sensitivity improvement without compromising overall structural integrity.
3Strength
If the recess portion is filled with epoxy resin to attach the supporting substrate, then attachment strength is improved, but light sensitivity is reduced due to light absorption and bubble formation
Solution Approach 1:
The light shield film is divided by the opening slit to create a pathway for adhesive supply. This segmentation allows the adhesive to fill the recess portion uniformly without trapping bubbles, achieving both strong attachment and maintained light sensitivity.
Solution Approach 2:
The opening slit enables continuous supply of adhesive material to the recess portion during the attachment process. This continuous flow prevents bubble entrapment and ensures uniform adhesive distribution, maintaining both attachment strength and light sensitivity.
Data Source
AI summary
In a semiconductor device in which a glass substrate is attached to a surface of a semiconductor die with an adhesive layer being interposed therebetween, it is an object to fill a recess portion of an insulation film formed on a photodiode with the adhesive layer without bubbles therein. In a semiconductor die in which an optical semiconductor integrated circuit including a photodiode having a recess portion of an interlayer insulation film in the upper portion, an NPN bipolar transistor, and so on are formed, generally, a light shield film covers a portion except the recess portion region on the photodiode and except a dicing region. In the invention, an opening slit is further formed in the light shield film, extending from the recess portion to the outside of the recess portion, so as to attain the object.