Influence of rapid thermal annealing on the wafer warpage in 3D NAND flash memory

Li, Qi; Zou, Xingqi; Gao, Jing; Chuan, Yang; Ding, Lei; Wu, Zhipeng; Li, Na; Zhang, Sen; Huo, Zongliang

doi:10.1088/1361-6641/aafccd

Cited by 19 publications

(9 citation statements)

References 19 publications

(18 reference statements)

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“…The bit density is generally increased by stacking more layers in 3D NAND Flash [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. However, stacking more layers makes integrated processes more complex, leading to worse wafer stress [ 9 , 10 , 11 ] and leakage caused by fluorine attack [ 12 ]. Meanwhile, the doping profile of vertical select transistors needs to be well controlled for better performance.…”

Section: Introductionmentioning

confidence: 99%

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

et al. 2023

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The bit density is generally increased by stacking more layers in 3D NAND Flash. Lowering dopant activation of select transistors results from complex integrated processes. To improve channel dopant activation, the test structure of vertical channel transistors was used to investigate the influence of laser thermal annealing on dopant activation. The activation of channel doping by different thermal annealing methods was compared. The laser thermal annealing enhanced the channel activation rate by at least 23% more than limited temperature rapid thermal annealing. We then comprehensively explore the laser thermal annealing energy density on the influence of Poly-Si grain size and device performance. A clear correlation between grain size mean and grain size sigma, large grain size mean and sigma with large laser thermal annealing energy density. Large laser thermal annealing energy density leads to tightening threshold voltage and subthreshold swing distribution since Poly-Si grain size regrows for better grain size distribution with local grains optimization. As an enabler for next-generation technologies, laser thermal annealing will be highly applied in 3D NAND Flash for better device performance with stacking more layers, and opening new opportunities of novel 3D architectures in the semiconductor industry.

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Section: Introductionmentioning

confidence: 99%

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

et al. 2023

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“…Shin and Lee concluded that the increased gravitational force used when depositing thin layers reduces warpage (Shin and Lee, 2014). Qi Li et al found that the annealing temperature helped control warpage (Li et al, 2019). S. Bhagavat, I. Kao proposed controlling the parameters and boundary conditions to reduce warping of the substrate used in wafers during ingot sawing (Bhagavat and Kao, 2008).C.…”

Section: Introductionmentioning

confidence: 99%

Reduction of the warping of a silicon wafer coated with two thin layers by minimal geometric modifications

Fatmi

Belhenini

Tougui

2023

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Purpose The aim of this study is to make a contribution towards reducing the deflections of silicon wafers. The deformation of silicon wafers used in the manufacture of electronic micro-components is one of the most common problems encountered by industrialists during manufacturing. Stack warping is typically produced during the process of depositing thin layers on a substrate. This is due to the thermal-mechanical stresses caused by the difference between the thermal expansion coefficients of the materials. Reducing wafer deformation is essential to increase reliability and improve quality. In this paper, the authors propose an approach based on minimal geometrical modifications to reduce the deformation of a silicon wafer coated with two thin layers. Numerical finite element models have been developed to evaluate the impact of geometrical modifications on warping amplitude. Finite element models have been validated compared with experimental models. The results obtained are encouraging and clearly show a considerable reduction in wafer deformation. Design/methodology/approach Reducing wafer deformation is essential to increase reliability and improve quality. In this paper, the authors propose an approach based on minimal geometrical modifications to reduce the deformation of a silicon wafer coated with two thin layers. Numerical finite element models have been developed to evaluate the impact of geometrical modifications on warping amplitude. Finite element models have been validated compared with experimental models. Findings The results obtained are encouraging and clearly show a considerable reduction in wafer deformation. Originality/value This paper describes the influence of geometric modification on wafer deformation. The work show also the cruciality of stress reduction in the purpose to obtain less wafer deformation.

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“…Tungsten (W), due to high melting point, high electrical conductivity, and superior accessibility, [1][2][3][4][5] has been widely used as the word line metal film of 3D NAND flash devices, dynamic random access memory (DRAM) devices, and phase-change memory (PCM) devices [6][7][8][9][10] for decades. Molybdenum (Mo) and tungsten are subgroup six (VIB) elements and have similar physical and chemical properties.…”

Section: Introductionmentioning

confidence: 99%

Tensile and Compressive Mechanical Properties of Polycrystalline Tungsten–Molybdenum Alloy

Zhang

et al. 2022

Physica Status Solidi (a)

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To clarify the mechanical performance of word line metal film, molecular dynamics simulations to explore the tensile and compressive responses of W–Mo alloys are utilized. The results reveal that all the mechanical parameters, including Young's modulus, yield strength, flow stress, and platform stress, decrease linearly by about 13–20% with the increase in Mo concentration. The development of the amorphous region and grain boundaries (GBs) dominates the deformation process of W–Mo alloys under tensile and compressive loadings. A large number of body‐centered cubic atoms transforms into amorphous atoms during the loading process. The average shear strain is independent of Mo concentration, and the value of the W50Mo50 sample under tension and compression rises to 1.11 and 1.98, respectively, as the strain increases from 0 to 0.6. In addition, the temperature sensitivity of mechanical features is independent of the concentration of Mo. The results may provide guidance and reference for the industrial application of W–Mo metal films in semiconductor manufacturing.

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Influence of rapid thermal annealing on the wafer warpage in 3D NAND flash memory

Cited by 19 publications

References 19 publications

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

Activation Enhancement and Grain Size Improvement for Poly-Si Channel Vertical Transistor by Laser Thermal Annealing in 3D NAND Flash

Reduction of the warping of a silicon wafer coated with two thin layers by minimal geometric modifications

Tensile and Compressive Mechanical Properties of Polycrystalline Tungsten–Molybdenum Alloy

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