Characteristic of SiC Slurry in Ultra Precision Lapping of Sapphire Substrates

Yin, Tao; Wang, Zhi Da; Doi, Toshiro; Kurokawa, Syuhei; Tan, Zhe; Ding, Xiao Kang; Lin, Huan

doi:10.1007/s12541-021-00521-1

Cited by 4 publications

(2 citation statements)

References 30 publications

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“…For the lapping of sapphire wafer, scholars have studied the lapping plate type, processing form, process condition, processing efficiency, and surface damage. For example, for lapping with free abrasive, Yin [10] et al have obtained a smooth surface having a surface roughness of 1.9 nm by lapping single crystal sapphire with free SiC abrasive, but the associated material removal rate (MRR) is only 508 nm/h, which is far lower than that when using a fixed-abrasive lapping plate. Lu [11,12] et al the lapping plate with Fenton reaction is prepared, which can greatly improve the lapping MRR.…”

Section: Introductionmentioning

confidence: 99%

Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

Xiong

Nie²,

Lu³

et al. 2022

Int J Adv Manuf Technol

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To enhance the lapping effects of sapphire wafers, two vitrified bonded fixed-abrasive lapping plates with different mechanical properties were developed and used to lap sapphire wafers to evaluate the effects of lapping time and dressing cycle on the lapping process effect and the stability of the lapping plates. The results indicate that the lapping material removal rate (MRR) and surface roughness (Ra) of the workpiece decrease with increasing lapping time; the higher the hardness of the lapping plate, the larger the MRR and Ra. There are differences in the primary wear forms between the two types of plates, with the high-hardness plate being mainly abrasive wear and abrasive breakage, while the low-hardness plate being mainly abrasive peeling off and abrasive wear. The two plates have the same trend in material removal for sapphire wafers -increasing the lapping time, the MRR is found to be gradually decreased and plateaued after 30 min, which is only about 20% of that of the initial lapping time, resulting in the plates needing to be dressed. After dressing the lapping plates, the plate processing performance returns to its initial state; the MRR deviation is less than 10% within the same period of use after several dressings.

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Section: Introductionmentioning

confidence: 99%

Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

Xiong

Nie²,

Lu³

et al. 2022

Int J Adv Manuf Technol

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show abstract

“…In addition, MRR increased with an increase in lapping speed and lapping pressure and the optimised lapping parameters were used to process sapphire sliced wafers with an MRR of 40 mm/min. To reduce the damage on the surface of sapphire wafers caused by abrasive particles during lapping, Yin et al (2021) proposed an ultrasonic-assisted method to select SiC abrasives and prepare the corresponding lapping slurry, with which the sapphire wafers were processed and their lapping performance was analysed. The results revealed that abrasive size was the main factor affecting the MRR and surface roughness (Ra) of sapphire wafers and increasing abrasive concentration and lapping speed significantly improved MRR.…”

Section: Introductionmentioning

confidence: 99%

Surface quality prediction and lapping process optimisation on the fixed-abrasive lapping plate of sapphire wafers

Yan

Wang²,

Liu³

2022

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Purpose Lapping is a vital flattening process to improve the quality of processed semiconductor wafers such as single-crystal sapphire wafers. This study aims to optimise the lapping process of the fixed-abrasive lapping plate of sapphire wafers with good overall performance [i.e. high material removal rate (MRR), small surface roughness (Ra) of the wafers after lapping and small lapping plate wear ratio (η)]. Design/methodology/approach The influence of process parameters such as lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed on MRR, Ra and η of lapping-processed sapphire wafers was studied, and the results were combined with experimental data to establish a regression model. The multi-evaluation index optimisation problem was transformed into a single-index optimisation problem via an entropy method and the grey relational analysis (GRA) to comprehensively evaluate the performance of each parameter. Findings The results revealed that lapping time, abrasive size, abrasive concentration, lapping pressure and lapping speed had different influence degrees on MRR, Ra and η. Among these parameters, lapping time, lapping speed and abrasive size had the most significant effects on MRR, Ra and η, and the established regression equations predicted the response values of MRR, Ra and η to be 99.56%, 99.51% and 93.88% and the relative errors between the predicted and actual measured values were <12%, respectively. With increased lapping time, MRR, Ra and η gradually decreased. With increased abrasive size, MRR increased nearly linearly, whereas Ra and η initially decreased but subsequently increased. With an increase in abrasive concentration, MRR, Ra and η initially increased but subsequently decreased. With increased lapping pressure, MRR and η increased nearly linearly and continuously, whereas Ra decreased nearly linearly and continuously. With increased lapping speed, Ra initially decreased sharply but subsequently increased gradually, whereas η initially increased sharply but subsequently decreased gradually; however, the change in MRR was not significant. Comparing the optimised results obtained via the analysis of influence law, the parameters optimised via the entropy method and GRA were used to obtain sapphire wafers lapping with an MRR of 4.26 µm/min, Ra of 0.141 µm and η of 25.08, and the lapping effect was significantly improved. Originality/value Therefore, GRA can provide new ideas for ultra-precision processing and process optimisation of semiconductor materials such as sapphire wafers.

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Optimisation of free-abrasive assisted lapping process with vitrified bonded diamond plates for sapphire substrates

Deng,

Xiong,

Nie

et al. 2024

Precision Engineering

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Characteristic of SiC Slurry in Ultra Precision Lapping of Sapphire Substrates

Cited by 4 publications

References 30 publications

Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

Processing performance of vitrified bonded fixed-abrasive lapping plates for sapphire wafers

Surface quality prediction and lapping process optimisation on the fixed-abrasive lapping plate of sapphire wafers

Optimisation of free-abrasive assisted lapping process with vitrified bonded diamond plates for sapphire substrates

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