Non-Photoreactive IR Blocking Layer for Semiconductor Devices
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Solution Overview
Problem
Existing methods for forming patterned radiation blocking layers in semiconductor devices require expensive and time-consuming two-step photo-lithography processes, and conventional IR blocking layers are inadequate in blocking infrared radiation due to non-uniform coating and high cost of photo-definable materials.
Innovation Solution
A method using a preformed, non-photoreactive IR blocking layer that conforms to the topography of the semiconductor device, allowing for a single photo-lithography process to form openings, and a laminated bi-layer structure with a photoreactive passivation layer to expose pads for electrical connections, reducing costs and improving radiation blocking efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photo-definable IR blocking layer is used and patterned through photo-lithography, then openings can be formed to expose ball-pads, but the process requires expensive photo-lithography equipment and multiple processing steps
Solution Approach 1:
The patent divides the manufacturing process into two independent stages: (1) forming the IR blocking layer without requiring photo-lithography patterning, and (2) performing photo-lithography only on the passivation layer. This segmentation eliminates the need for photo-lithography equipment for the IR blocking layer, reducing capital expenses and simplifying the overall manufacturing process while maintaining the ability to expose ball-pads through the patterned passivation layer
Solution Approach 2:
The IR blocking layer is formed in advance using spin-coating or other deposition methods before the passivation layer is applied. This preliminary formation of the IR blocking layer eliminates the need for subsequent photo-lithography processing of the IR blocking material, reducing both equipment requirements and processing time while ensuring proper infrared radiation blocking is established before final pad exposure
2Object-affected harmful factors
If a thick IR blocking layer is used to effectively block infrared radiation, then radiation blocking efficiency improves, but photo-lithography cannot penetrate through the full thickness of the blocking layer
Solution Approach 1:
The patent separates the functions of infrared radiation blocking and photo-lithography patterning into two different material layers: the IR blocking layer (non-photoreactive) handles radiation blocking with sufficient thickness, while the passivation layer (photo-definable) handles the photo-lithography patterning. This segmentation allows each layer to be optimized for its specific function without compromise
Solution Approach 2:
The passivation layer acts as an intermediary between the thick IR blocking layer and the photo-lithography process. It provides the necessary photo-definable properties for pattern formation while allowing the underlying IR blocking layer to maintain its radiation-blocking function with adequate thickness
3Manufacturing precision
If photo-definable IR blocking materials are used, then the layer can be patterned to expose ball-pads, but the cost of materials and processing increases
Solution Approach 1:
The patent segments the functional requirements by assigning the IR blocking function to a non-photoreactive material layer and the patterning function to a separate photo-definable passivation layer. This eliminates the need for expensive photo-definable IR blocking materials while maintaining precise pad exposure capability through the passivation layer
Solution Approach 2:
The patent uses a cost-effective non-photoreactive IR blocking material that can be applied via simple spin-coating or deposition processes. The expensive photo-lithography step is performed only on the thinner passivation layer, not on the bulk IR blocking material, significantly reducing material and processing costs while maintaining manufacturing precision
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
This approach reduces capital expenses by minimizing the need for expensive photo-lithography tools and enhances radiation blocking by using a thick, non-photoreactive IR blocking layer that effectively absorbs infrared radiation, improving the efficiency and cost-effectiveness of the process.
Implementation Method 1
a first film comprising infrared blocking material that is at least substantially non-photoreactive
Implementation Method 2
photo-patterning a second film of a photo-definable material on the first film and thereby exposing portions of the first film aligned with corresponding traces
Implementation Method 3
a conventional spin-on process in which a liquid IR blocking material is deposited onto the workpiece and the workpiece is rotated to spread the liquid IR blocking material
Data Source
AI summary
Several embodiments for semiconductor devices and methods for forming semiconductor devices are disclosed herein. One embodiment is directed to a method for manufacturing a microelectronic imager having a die including an image sensor, an integrated circuit electrically coupled to the image sensor, and electrical connectors electrically coupled to the integrated circuit. The method can comprise covering the electrical connectors with a radiation blocking layer and forming apertures aligned with the electrical connectors through a layer of photo-resist on the radiation blocking layer. The radiation blocking layer is not photoreactive such that it cannot be patterned using radiation. The method further includes etching openings in the radiation blocking layer through the apertures of the photo-resist layer.