Infrared Emission Monitoring for Plasma Dicing End Point Detection
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Solution Overview
Problem
The plasma dicing process generates high temperatures, leading to potential damage from tape deformation and outgassing, and existing methods for detecting the end point are either too late or rely on estimates, making it difficult to manage heat effectively and detect declamping issues without causing overheating.
Innovation Solution
Monitoring infrared emission from dicing lanes to detect the final phase of the plasma dicing process, allowing for adjustments in process variables such as etch rate and cooling to prevent overheating and declamping, using a pyrometer or infrared camera for cost-effective and accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical emission end point detection is used to signal singulation, then the end point can be detected, but the detection occurs too late to prevent tape overheating and burning
Solution Approach 1:
The patent applies preliminary action by detecting the final phase of plasma dicing through infrared emission monitoring before singulation occurs. This early detection enables process adjustments (reducing RF power, increasing cooling) to be made in advance, preventing tape overheating and burning that would occur with conventional end-point detection methods
2Object-affected harmful factors
If a less energetic etch rate is used prior to end point to prevent tape damage, then tape burning is reduced, but the etching process becomes less efficient and takes longer
Solution Approach 1:
The patent applies dynamics by dynamically adjusting the etch rate based on real-time detection of the final phase. The system transitions from a high etch rate during the main dicing process to a lower etch rate only when the final phase is detected, optimizing both productivity and tape protection without unnecessary slowdown
Solution Approach 2:
The patent detects the final phase in advance and prepares for rate reduction before tape damage occurs. This preliminary detection enables timely process adjustment that prevents tape burning while maintaining high productivity during the majority of the etching process
3Adaptability or versatility
If wafer thickness variation is accommodated by using estimated soft landing point, then inconsistent wafers can be processed, but the estimated activation point becomes inaccurate reducing process efficiency
Solution Approach 1:
The patent applies feedback by using infrared emission monitoring to detect the final phase based on actual process conditions rather than estimates. This real-time feedback enables accurate detection regardless of wafer thickness variations, eliminating the need for conservative timing estimates and improving overall process efficiency
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
Enables early detection of the plasma dicing end point, allowing for optimized heat management and preventing damage, while also predicting the end point in advance, thus improving process efficiency and reducing manufacturing costs.
Implementation Method 1
The process of plasma dicing can generate a significant amount of heat due to exothermic chemical reactions, ion bombardments and emission from the plasma
Implementation Method 2
The process of plasma dicing can generate a significant amount of heat due to exothermic chemical reactions, ion bombardments and emission from the plasma
Implementation Method 3
The process of plasma dicing can generate a significant amount of heat due to exothermic chemical reactions, ion bombardments and emission from the plasma
Implementation Method 4
Typically, the substrate is clamped to a cooled platen using electrostatic or mechanical methods or combination of both methods
Implementation Method 5
infrared emission emanating from at least a portion of the dicing lanes is monitored so that an increase in infrared emission from the dicing lanes is observed
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
According to the invention there is provided a method of detecting a condition associated with a final phase of a plasma dicing process comprising the steps of: providing a non-metallic substrate having a plurality of dicing lanes defined thereon; plasma etching through the substrate along the dicing lanes, wherein during the plasma etching infrared emission emanating from at least a portion of the dicing lanes is monitored so that an increase in infrared emission from the dicing lanes is observed as the final phase of the plasma dicing operation is entered; and detecting the condition associated with the final phase of the plasma dicing from the monitored infrared emission.