Experimental Study on Temperature during Wire Saw Slicing

2013 ◽  
Vol 481 ◽  
pp. 153-157
Author(s):  
Chun Yan Yao ◽  
Zong Hua Xu ◽  
Wei Zhang ◽  
Qiao Fang Zhang ◽  
Wei Peng

Heat generated during wire saw slicing can cause silicon temperature raise and make silicon wafer warpage, especially for larger silicon wafers. In order to study the wire saw effect on silicon temperature during slicing process, three kinds of wire saw, mainly semi-fixed abrasive wire saw and traditional wire saw, are applied for slicing silicon ingot. In this paper, the thermocouple is used to measure the temperature of the silicon during wire saw slicing. The experiment results show that the temperature of the silicon increases along with the wire saw working direction and reaches maximum value near the outlet position of silicon. The temperature of the silicon sliced by semi-fixed abrasive wire saw is lower than that sliced by traditional wire saw.

1998 ◽  
Vol 120 (2) ◽  
pp. 123-128 ◽  
Author(s):  
J. Li ◽  
I. Kao ◽  
V. Prasad

Wire saw slicing is a cost effective technology with high surface quality for slicing large diameter silicon wafers. Though wire saws have been deployed to cut polycrystalline and single crystal silicon ingot since the early 1990s, very little is known about the fundamental cutting process. We investigate this manufacturing process and propose a contact stress model of wire saw slicing that illustrates the interactions among the wire, ingot, and abrasives (e.g., SiC) carried by the slurry. Stresses created by wire saw slicing silicon wafers are analyzed in this paper. During the cutting process, the wire moves at high speed (5–15 m/s) with respect to the silicon ingot. The abrasives in the slurry are lose third-body particles caught between the wire and ingot at the contact surface. The forces applied by the wire carry the abrasive particles and cause them to roll on the surface and at the same time to be constrained to indent the surface. Such rolling-indenting interactions result in the formation of isolated chips and surface cracks. The cracks and discontinuity on the surface also cause high stress concentration. As a result, the material is cut and removed. The stress fields of a single circular cone of the abrasive particle indenting on silicon crystal with normal and tangential forces can be calculated and analyzed from the modeling equations and boundary conditions. The stresses are expressed with dimensionless stress measures, as functions of normalized geometric parameters. The results show that the maximum normal stress occurs at the indentation point, while the maximum shear stress (σzx) occurs below the surface of contact, as expected. Such subsurface shear facilitates the peeling effects of the silicon cracks. Both the normal and tangential forces applied at the contacts are incorporated in the model. The model is very effective in explaining and predicting the behaviors and distributions of stresses during the cutting process, and can be used to determine the optimal geometry of the abrasive particles in the rolling-indenting process.


2011 ◽  
Vol 175 ◽  
pp. 294-299 ◽  
Author(s):  
Yong Peng Li ◽  
Hui Huang ◽  
Xi Peng Xu

Fixed-abrasive wire saw, with its ability to cut hard brittle material, such as silicon ingots, crystals and quartz, has emerged as a leading technology for production in semiconductor and photovoltaic industry. There are some defects in conventional fixed-abrasive wire saw such as significant low holding abrasive ability, low machining efficiency, high running costs, etc. A new fixed-abrasive wire, namely brazed diamond wires have been developed to overcome these problems. In this paper, brazed diamond wire were carried out to braze two different size diamond grits onto two different thin steel wires by using a nickel-based powder as brazing alloy. The mechanical properties of brazed diamond wire were evaluated by tensile and breaking twist experiment. The experimental results showed that the heating in the brazing process has litter influence on the wire mechanical properties. The addition of brazed alloy and diamond grits sharply decreased the wire mechanical properties significantly, both in the tensile strength and breaking twist angle. Bigger diamond grit would make the accumulation of brazed alloy which leaded to the deterioration of diameter consistency of wires.


2007 ◽  
Vol 359-360 ◽  
pp. 450-454 ◽  
Author(s):  
Yu Fei Gao ◽  
Pei Qi Ge ◽  
Zhi Jian Hou

The physical model of fixed-abrasive diamond wire-sawing monocrystalline silicon was founded to analyze the elastic deformation of the wire, supposing that every grit was connected to the surface of the wire by a spring. Ignoring lateral vibration of the wire, the geometrical model of wire-sawing was founded; the average cut depth of single grit was calculated theoretically. Based the indentation fracture mechanics and investigations on brittle-ductile transition of machining monocrystalline silicon, the removal mechanism and surface formation was studied theoretically. It shows that in the case of wire-sawing velocity of 10m/s or higher, infeed velocity of 0.20mm/s and diamond grain size of 64μm or smaller, the chip formation and material removal is in a brittle regime mainly, but the silicon wafer surface formation is sawed in a ductile regime. The size of the abrasives, the wire-saw velocity and infeed velocity can influence the sawing process obviously.


2011 ◽  
Vol 487 ◽  
pp. 233-237 ◽  
Author(s):  
Guang Qiu Hu ◽  
Jing Lu ◽  
Jian Yun Shen ◽  
Xi Peng Xu

The surface roughness and surface morphology of silicon wafers polished by three different polishing methods were analyzed in this paper. A polishing pad was prepared by means of sol-gel technology as semi-fixed abrasive tool. An electroplated polishing pad was chosen as fixed abrasive tool. And a polishing cloth was chosen as free abrasive tool. The results showed that the surface of silicon wafer polished by the sol-gel polishing pad was superior to the other two. It was easy to get mirror effect with few scratches while the free abrasive and fixed abrasive got lots of scratches on 23silicon wafers. The surface roughness of silicon wafer polished by the sol-gel polishing pad reached 1.41nm measured by atomic force microscope (AFM).


2007 ◽  
Vol 329 ◽  
pp. 361-366
Author(s):  
J.H. Liu ◽  
Zhi Jian Pei ◽  
Graham R. Fisher

The majority of integrated circuits are built on silicon wafers. To manufacture high-quality silicon wafers, a series of processes are needed. After a wire sawing process slices silicon ingots into wafers, grinding processes can be used to flatten the sliced wafers. This paper reports three experimental investigations on wafer grinding. The first investigation was to study the effectiveness of soft-pad grinding in removing the wire-sawing induced waviness. The second was to explore the capability of grinding in achieving super flatness. The third was to study the effects of grinding parameters on wafer flatness.


2013 ◽  
Vol 797 ◽  
pp. 685-690 ◽  
Author(s):  
Ren Ke Kang ◽  
Yan Fen Zeng ◽  
Shang Gao ◽  
Zhi Gang Dong ◽  
Dong Ming Guo

Wire saw process is widely used in the machining of hard and brittle materials with low surface damage and high efficiency. Cutting of silicon wafers in integrated circuit (IC), semiconductor and photovoltaic solar industries is also generally using wire saw process. However, the surface layer damage induced by wire saw process will seriously decrease the wafer quality and increase the process time and production costs of the post grinding and polishing. The surface layer qualities of the silicon wafers sawed by the different wire saw processes was investigated in this paper. The characteristics of surface roughness, surface topography and subsurface damage of silicon wafers sliced by the fixed abrasive and the loose abrasive wire sawing respectively were compared and the corresponding reasons were analyzed.


Author(s):  
Shujuan Li ◽  
Aofei Tang ◽  
Yong Liu ◽  
Jiabin Wang ◽  
Dan Cui ◽  
...  

Free abrasive diamond wire saw machining is often used to cut hard and brittle materials, especially for wafers in the semiconductor and optoelectronics industries. Wire saws, both free and fixed abrasive, have excellent flexibility, as compared to inner circular saws, outer saws, and ribbon saws, as they produce a narrower kerf, lower cutting forces, and less material waste. However, fixed abrasive wire saw machining is being considered more and more due to its potential for increased productivity and the fact that it is more environmentally friendly as it does not use special coolants that must be carefully disposed. The cutting forces generated during the wire saw process strongly affect the quality of the produced parts. However, the relationship between these forces and the process parameters has only been explored qualitatively. Based on analyzing the forces generated from the chip formation and friction of a single abrasive, this study derives an analytical cutting force model for the wire saw machining process. The analytical model explains qualitative observations seen in the literature describing the relationship between the cutting forces and the wafer feed rate, wire velocity, and contact length between the wire and wafer. Extensive experimental work is conducted to validate the analytical force model. Silicon carbide (SiC) monocrystal, which is employed extensively in the fields of microelectronics and optoelectronics and is known to be particularly challenging to process due to its extremely high hardness and brittleness, is used as the material in these experimental studies. The results show that the analytical force model can predict the cutting forces when wire saw machining SiC monocrystal wafers with average errors between the experimental and predicted normal and tangential forces of 9.98% and 12.1%, respectively.


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