Backside-Doped Semiconductor Body With Laser-Activated Impurity Profile
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in balancing conflicting requirements such as doping profiles, thermal budgets, and mechanical stability when processing both sides of a semiconductor wafer, limiting manufacturing flexibility.
Innovation Solution
A method involving forming semiconductor device elements on one surface, attaching the wafer to a carrier, implanting ions through the opposite surface, and using laser pulses to irradiate the surface for controlled doping and activation, allowing for flexible manufacturing by adjusting temperature profiles and penetration depths without overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ions are implanted through the second surface into the semiconductor body, then doping profiles can be optimized, but thermal budget constraints from previous front side processing limit the achievable doping profiles
Solution Approach 1:
The manufacturing process is divided into two independent stages: front side processing (forming semiconductor device elements) and back side processing (ion implantation through the second surface). This segmentation allows each side to be processed independently with optimized parameters, eliminating the thermal budget constraint that would exist in a sequential single-side process.
Solution Approach 2:
Instead of the conventional approach of processing the front side first and then the back side with limited thermal budget, the patent inverts the thermal management strategy by using laser irradiation after ion implantation to activate dopants. This allows high-energy ion implantation to be performed first, followed by localized thermal activation that does not compromise the previously formed front side structures.
2Manufacturing precision
If laser pulses are used to irradiate the surface region, then doping activation and thermal processes can be controlled precisely, but overheating may occur
Solution Approach 1:
The laser irradiation is applied in periodic pulses rather than continuous exposure. This pulsed approach allows heat to dissipate between pulses, preventing cumulative overheating while still achieving the required thermal activation for dopant activation and diffusion control.
Solution Approach 2:
The laser irradiation is applied locally to specific surface regions rather than uniformly across the entire wafer. This localized treatment activates dopants only in the implanted regions while minimizing thermal exposure to other areas, preventing overheating and damage to previously formed structures.
3Strength
If the semiconductor body is attached to a carrier via the wiring area, then mechanical stability is improved during processing, but the carrier must be removed afterward
Solution Approach 1:
The carrier is attached to the semiconductor body before ion implantation and laser irradiation processes. This preliminary attachment provides mechanical stability during these high-stress operations, and the carrier is designed to be removed after processing is complete, serving its purpose temporarily.
Solution Approach 2:
The carrier acts as an intermediary support structure during critical processing steps. It provides the necessary mechanical stability without becoming part of the final device, allowing complex processing operations to be performed on thin or fragile semiconductor bodies.
4Stability of the object's composition
If standard wafer sizes and thicknesses are used, then manufacturing consistency is maintained, but flexibility in optimizing doping profiles and thermal budgets is limited
Solution Approach 1:
By segmenting the processing into independent front side and back side operations with the ability to attach to carriers, the process can accommodate non-standard wafer sizes and thicknesses. Each side can be processed with optimized parameters independent of the other, providing flexibility while maintaining consistency through standardized process modules.
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 enhances manufacturing flexibility by optimizing doping profiles and thermal processes, enabling precise control over impurity concentrations and minority carrier lifetimes, thereby improving semiconductor device performance.
Implementation Method 1
irradiating a surface region of the semiconductor body at the second surface with a plurality of laser pulses
Implementation Method 2
The plurality of laser pulses is/are used for electrically activating and adjusting an impurity concentration profile
Implementation Method 3
implanting ions through the second surface into the semiconductor body. The ions are ions of a doping element, or ions, which induce doping by complex formation
Data Source
AI summary
A semiconductor device includes: a semiconductor body having a first surface and a second surface; a plurality of semiconductor device elements in the semiconductor body at the first surface; a wiring area over the first surface of the semiconductor body; and an impurity in the semiconductor body. A profile of concentration of the impurity has a penetration depth from the second surface into the semiconductor body along a vertical direction. The profile of concentration has a concentration plateau along a vertical segment ranging from 30% to 70% of the penetration depth, the plateau having a fluctuation of the concentration of less than 20%.