Stacked Memory Die Layout for Precise Joint Gap Measurement
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Solution Overview
Problem
In semiconductor manufacturing, particularly for high bandwidth memory (HBM) products, measuring the joint gap between stacked memory chips is challenging due to errors from chip thickness variations and the blocking effect of metal layers in the active layer, which hinders direct infrared interferometer measurements.
Innovation Solution
Incorporating light transmitting regions in the memory dies allows for direct measurement of joint gaps by passing light through these regions and detecting reflected light to accurately determine distances between memory dies, thereby overcoming the limitations of indirect measurement methods and metal layer interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement methods using infrared interferometer are used, then measurement precision is improved, but the metal layers in the active layer block infrared light preventing measurement
Solution Approach 1:
The active layer is divided into a measurement region containing metal layers and a scribe lane region without metal layers. The light transmitting region is formed specifically in the scribe lane region, separating the measurement function from the active circuit region, allowing infrared light to pass through without being blocked by metal layers.
Solution Approach 2:
The scribe lane region acts as an intermediary area that provides a light transmission path free of metal layers. By forming the light transmitting region in this intermediate zone between active dies, infrared light can reach the memory chip for measurement without being blocked by the metal layers in the active layer.
2Object-affected harmful factors
If indirect measurement methods such as bond line thickness measurement are used, then metal layer blocking is avoided, but measurement precision deteriorates due to chip thickness variations
Solution Approach 1:
The measurement function is extracted from the active layer and relocated to the scribe lane region. By forming the light transmitting region in the scribe lane region separate from the active circuits, direct infrared measurement can be performed without being affected by chip thickness variations that plague indirect measurement methods.
3Measurement precision
If light transmitting regions are formed in the active layer, then direct measurement is enabled, but the active layer structure is modified
Solution Approach 1:
The active layer is segmented into a measurement region and a scribe lane region. The light transmitting region is formed only in the scribe lane region, maintaining the integrity of the active layer structure in the measurement region while enabling direct infrared measurement through the scribe lane region.
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 enables precise measurement of joint gaps, reducing errors in the semiconductor manufacturing process, such as thermal compression bonding, by allowing direct light transmission and reflection for distance measurement.
Implementation Method 1
a first light transmitting region configured to pass light incident from the first upper surface to the second memory die
Implementation Method 2
measuring a distance between the first memory die and a second memory die through first detected light, wherein the second memory die is positioned immediately below the first memory die among the plurality of memory dies, and wherein the first detected light is formed by the first light sequentially passing through the first light transmitting region
Data Source
AI summary
A method of manufacturing a semiconductor package includes disposing a buffer die on a support carrier; forming a plurality of memory dies, each of the plurality of memory dies having a body layer and an active layer on a surface of the body layer, wherein the body layer includes a light transmitting region; stacking the plurality of memory dies on the buffer die in a vertical direction to form a semiconductor device; measuring respective distances between the buffer die and the plurality of memory dies by irradiating light on the semiconductor device in the vertical direction; and forming a molding member encapsulating the semiconductor device.