CMP Polishing Pad Groove Layout for Uniform Face-Up Wafer Planarization

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Solution Overview

Problem

Current semiconductor wafer thinning and package planarization techniques face challenges in achieving uniform polishing and minimizing wafer damage due to inadequate control over pressure and down force during face-up wafer CMP processes.

Innovation Solution

A chemical mechanical polishing (CMP) apparatus with a polishing pad that includes a sub-pad portion and a top pad portion, featuring a slurry inlet and grooves, is used to polish the wafer in a face-up orientation, allowing for improved slurry distribution and mechanical support, thereby enhancing polishing uniformity and reducing wafer loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If face-up wafer CMP process is used for thinning and planarization, then polishing accessibility is improved, but pressure and down force control becomes inadequate leading to poor polishing uniformity and increased wafer damage

Engineering Contradiction:

Improvepolishing accessibilityVSAvoidpolishing uniformity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The polishing pad is segmented into a head portion and a tail portion along the polishing direction, with different groove patterns in each section. The head portion has grooves with larger pitch to facilitate slurry penetration and removal of polished debris, while the tail portion has grooves with smaller pitch for refined polishing, thereby achieving uniform polishing across the wafer surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the polishing pad are designed with different groove characteristics. The head portion features grooves with larger pitch for aggressive material removal and slurry flow, while the tail portion has grooves with smaller pitch for finer polishing control. This local differentiation optimizes polishing uniformity across different zones of the wafer.

Inventive Principle:

Principle #3Local quality

2Device complexity

If conventional polishing pad design is used, then结构简单性 is maintained, but slurry distribution is inadequate leading to poor polishing uniformity

Engineering Contradiction:

Improvepad structure simplicityVSAvoidpolishing uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The polishing pad is divided into functional zones (head and tail portions) with distinct groove patterns. This segmentation enables optimized slurry distribution and debris removal in different polishing zones without requiring complex external control systems, maintaining structural simplicity while improving polishing uniformity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The groove patterns are designed with varying pitch in different directions and zones of the polishing pad. This dimensional variation in groove spacing creates optimized slurry flow paths and debris evacuation channels across the pad surface, enhancing polishing uniformity through geometric design rather than complex mechanical structures.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If inadequate groove design is used in polishing pad, then manufacturing simplicity is maintained, but polishing debris removal is insufficient leading to reduced polishing uniformity

Engineering Contradiction:

Improvepad manufacturing simplicityVSAvoidpolishing uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The groove pattern is segmented into different pitch zones along the polishing direction, with the head portion having larger pitch for debris removal and the tail portion having smaller pitch for surface finishing. This segmentation achieves effective debris evacuation and polishing uniformity through straightforward geometric design that remains manufacturable.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The groove pitch parameter is varied systematically along the polishing direction, with larger pitch in the head portion and smaller pitch in the tail portion. This parameter variation optimizes the balance between debris removal efficiency and polishing uniformity while maintaining manufacturing simplicity through regular geometric patterns.

Inventive Principle:

Principle #35Parameter changes

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

The solution achieves better control over polishing processes, improving polishing uniformity and reducing wafer damage, resulting in enhanced semiconductor package performance and reliability.

Implementation Method 1

Methodology Applied

Scientific EffectFluid flow distribution:

Implementation Method 2

Polishing is one of the most common technology for thinning the dies of the semiconductor wafer and for planarizing the topography of the semiconductor packages

Methodology Applied

Scientific EffectChemical mechanical polishing:

Data Source

PatentUS11878388B2Polishing pad, polishing apparatus and method of manufacturing semiconductor package using the same

Publication Date: 2024.01.23 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A polishing pad, a polishing apparatus and a method of manufacturing a semiconductor package using the same are provided. In some embodiments, a polishing pad includes a sub-pad portion and a top pad portion over the sub-pad portion. The top pad portion includes a plurality of grooves having a first width and a plurality of openings having a second width different from the first width, and the openings are located in a center zone of the polishing pad.