<p>Next-generation memory technology requires high-speed operation, high-capacity transmission, and low-power characteristics of memory semiconductors. Because performance improvements based on front-end processes face physical limitations, the importance of back-end packaging technology is increasing. In particular, high-bandwidth memory (HBM) and 3D NAND flash memory architectures in use today increase the integration density of the device through three-dimensional stacking and wafer-to-wafer bonding processes, thereby increasing the need for a technology capable of precisely dicing thick wafers without defects. In this study, multiscan stealth dicing of full-thickness silicon wafers was performed using a 1550 nm wavelength nanosecond pulsed laser and a high-numerical-aperture objective lens. Systematic analysis of the effects of process parameters such as average power, scan speed, and gap size on cutting quality revealed that under conditions of 0.11 W average power (1.83 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\:{\upmu\:}\)</EquationSource> </InlineEquation>J pulse energy), 300 mm/s scan speed, and 10 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\:{\upmu\:}\)</EquationSource> </InlineEquation>m gap, a uniform micro-crack layer and nearly vertical cut edges were formed. Under this process condition, the roughness of the cut surface was as low as approximately 0.68 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\:{\upmu\:}\)</EquationSource> </InlineEquation>m. Raman spectroscopy results identified the compressive stress at the upper (<InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\:-\)</EquationSource> </InlineEquation>460.04 MPa) and lower (<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(\:-\)</EquationSource> </InlineEquation>230.02 MPa) parts of the cut surface, and field-emission scanning electron microscopy was used to elucidate the structure of the micro-crack layers. The results of this study confirmed that focal shape changes, beam intensity distribution, and nonlinear absorption phenomena played decisive roles in the formation of the micro-crack layers. These findings demonstrate that high-precision and uniform micro-crack layer formation is possible even with nanosecond lasers, suggesting that this approach can contribute to the development of cost-effective and reliable next-generation semiconductor wafer dicing processes.</p>

Multiscan stealth dicing of full-thickness silicon wafers using a near-infrared nanosecond pulsed laser

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发表日期：

2026年4月11日

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Yeongil Son,
Minjun Lee,
Joonghan Shin

摘要

Next-generation memory technology requires high-speed operation, high-capacity transmission, and low-power characteristics of memory semiconductors. Because performance improvements based on front-end processes face physical limitations, the importance of back-end packaging technology is increasing. In particular, high-bandwidth memory (HBM) and 3D NAND flash memory architectures in use today increase the integration density of the device through three-dimensional stacking and wafer-to-wafer bonding processes, thereby increasing the need for a technology capable of precisely dicing thick wafers without defects. In this study, multiscan stealth dicing of full-thickness silicon wafers was performed using a 1550 nm wavelength nanosecond pulsed laser and a high-numerical-aperture objective lens. Systematic analysis of the effects of process parameters such as average power, scan speed, and gap size on cutting quality revealed that under conditions of 0.11 W average power (1.83 \(\:{\upmu\:}\) J pulse energy), 300 mm/s scan speed, and 10 \(\:{\upmu\:}\) m gap, a uniform micro-crack layer and nearly vertical cut edges were formed. Under this process condition, the roughness of the cut surface was as low as approximately 0.68 \(\:{\upmu\:}\) m. Raman spectroscopy results identified the compressive stress at the upper ( \(\:-\) 460.04 MPa) and lower ( \(\:-\) 230.02 MPa) parts of the cut surface, and field-emission scanning electron microscopy was used to elucidate the structure of the micro-crack layers. The results of this study confirmed that focal shape changes, beam intensity distribution, and nonlinear absorption phenomena played decisive roles in the formation of the micro-crack layers. These findings demonstrate that high-precision and uniform micro-crack layer formation is possible even with nanosecond lasers, suggesting that this approach can contribute to the development of cost-effective and reliable next-generation semiconductor wafer dicing processes.