Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing

The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectri...

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Main Authors: Xianglong Chu, Shitao Wang, Chunlei Li, Zhizhen Wang, Shenglin Ma, Daowei Wu, Hai Yuan, Bin You
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Micromachines
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Online Access:https://www.mdpi.com/2072-666X/16/5/582
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author Xianglong Chu
Shitao Wang
Chunlei Li
Zhizhen Wang
Shenglin Ma
Daowei Wu
Hai Yuan
Bin You
author_facet Xianglong Chu
Shitao Wang
Chunlei Li
Zhizhen Wang
Shenglin Ma
Daowei Wu
Hai Yuan
Bin You
author_sort Xianglong Chu
collection DOAJ
description The development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity of structures, combined with the temperature-dependent and viscoelastic properties of organic materials, make it increasingly difficult to predict the thermo-mechanical behavior of wafer-level Cu-PI RDL structures, posing a severe challenge in warpage prediction. This study models and simulates the thermo-mechanical response during the manufacturing process of Cu-PI RDL at the wafer level. A cross-scale wafer-level equivalent model was constructed using a two-level partitioning method, while the PI material properties were extracted via inverse fitting based on thermal warpage measurements. The warpage prediction results were compared against experimental data using the maximum warpage as the indicator to validate the extracted PI properties, yielding errors under less than 10% at typical process temperatures. The contribution of RDL build-up, wafer backgrinding, chemical mechanical polishing (CMP), and through-silicon via (TSV)/through-glass via (TGV) interposers to the warpage was also analyzed through simulation, providing insight for process risk evaluation. Finally, an artificial neural network was developed to correlate the copper ratios of four RDLs with the wafer warpages for a specific process scenario, demonstrating the potential for wafer-level warpage control through copper ratio regulation in RDLs.
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spelling doaj-art-65d759a3515e42b2bbf188533e2f70fe2025-08-20T03:47:57ZengMDPI AGMicromachines2072-666X2025-05-0116558210.3390/mi16050582Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During ManufacturingXianglong Chu0Shitao Wang1Chunlei Li2Zhizhen Wang3Shenglin Ma4Daowei Wu5Hai Yuan6Bin You7Pen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, China31002 PLA Troops, Beijing 100161, ChinaPen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, ChinaPen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, ChinaPen-Tung Sah Institute of Micro-Nano Science and Technology, Xiamen University, Xiamen 361005, ChinaXi’an Microelectronic Technology, Xi’an 710071, ChinaXi’an Microelectronic Technology, Xi’an 710071, China92858 PLA Troops, Ningbo 315800, ChinaThe development of chip manufacturing and advanced packaging technologies has significantly changed redistribution layers (RDLs), leading to shrinking line width/spacing, increasing the number of build-up layers and package size, and introducing organic materials such as polyimide (PI) for dielectrics. The fineness and complexity of structures, combined with the temperature-dependent and viscoelastic properties of organic materials, make it increasingly difficult to predict the thermo-mechanical behavior of wafer-level Cu-PI RDL structures, posing a severe challenge in warpage prediction. This study models and simulates the thermo-mechanical response during the manufacturing process of Cu-PI RDL at the wafer level. A cross-scale wafer-level equivalent model was constructed using a two-level partitioning method, while the PI material properties were extracted via inverse fitting based on thermal warpage measurements. The warpage prediction results were compared against experimental data using the maximum warpage as the indicator to validate the extracted PI properties, yielding errors under less than 10% at typical process temperatures. The contribution of RDL build-up, wafer backgrinding, chemical mechanical polishing (CMP), and through-silicon via (TSV)/through-glass via (TGV) interposers to the warpage was also analyzed through simulation, providing insight for process risk evaluation. Finally, an artificial neural network was developed to correlate the copper ratios of four RDLs with the wafer warpages for a specific process scenario, demonstrating the potential for wafer-level warpage control through copper ratio regulation in RDLs.https://www.mdpi.com/2072-666X/16/5/582equivalent modelredistribution layerwafer-level modelthermo-mechanicalpolyimidelayout effect
spellingShingle Xianglong Chu
Shitao Wang
Chunlei Li
Zhizhen Wang
Shenglin Ma
Daowei Wu
Hai Yuan
Bin You
Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
Micromachines
equivalent model
redistribution layer
wafer-level model
thermo-mechanical
polyimide
layout effect
title Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
title_full Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
title_fullStr Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
title_full_unstemmed Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
title_short Modeling and Simulation for Predicting Thermo-Mechanical Behavior of Wafer-Level Cu-PI RDLs During Manufacturing
title_sort modeling and simulation for predicting thermo mechanical behavior of wafer level cu pi rdls during manufacturing
topic equivalent model
redistribution layer
wafer-level model
thermo-mechanical
polyimide
layout effect
url https://www.mdpi.com/2072-666X/16/5/582
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