硅晶圆激光切割头及切割性能的研究

发布时间：2018-07-29 12:29

【摘要】：硅晶圆是一种常用的半导体材料。传统的硅晶圆切割方式为高速金刚石片接触式切割,切割过程中容易产生崩边等缺陷。激光切割作为非接触式切割方法,能够有效控制因接触时应力不均匀而产生的缺陷。首先,根据双振镜激光切割头的运动原理及光学系统基本原理,利用solidworks软件设计了硅晶圆切割专用切割头。主要设计内容包括切割头光纤连接模块、准直模块及机器人连接模块等。该切割头切割范围为200mm×200mm、切割精度为±0.05mm。经实际硅晶圆切割验证,本次设计双振镜激光切割头满足了设计及生产要求。利用设计的双振镜激光切割头进行硅晶圆的皮秒激光切割试验,通过改变皮秒激光输出功率,激光脉冲频率及切割速度等切割参数进行了切槽及隐晶切割试验。硅晶圆的切槽试验结果表明,切槽宽度与切槽深度随激光输出功率的增加而增大,随激光脉冲频率的增加而增大,随切割速度的增加而减少;切槽的挂渣高度及飞溅宽度随激光输出功率的增加而增大,随激光脉冲频率的增加而增大,随切割速度的增加而减小;通过正交试验,获得最佳工艺参数为激光功率30W、切割速度100mm/s、激光脉冲频率40kHz。通过扫描电子显微镜(SEM)及能谱分析仪(EDS)等对最佳工艺参数下的切槽进行分析,由分析结果可知,虽然皮秒激光切割过程中能量密度较高,但切槽周围几乎没有发现氧化现象,切槽周围物质的物理性化学性能得到了保证。硅晶圆的隐晶切割试验结果表明,最佳切割工艺参数为激光输出功率0.88W、激光脉冲频率80kHz、切割速度300mm/s;与硅晶圆的传统切缝崩边尺寸(70μm)比较,隐晶切割的崩边尺寸(40μm)明显减小,约减小了42%;与硅晶圆的水导激光切割的崩边尺寸(42μm)相比,隐晶切割的崩边尺寸减少了约5%。为了比较激光切割方法对硅晶圆的切割质量影响,采用了水导激光切割方法对硅晶圆进行了切割试验,试验结果表明,水导激光切槽最佳切割工艺参数为水压13MPa、功率2W、切割速度500mm/min,水导激光切断最佳工艺参数为水压13MPa、功率2W、切割速度200mm/min;在最佳切割工艺参数下,切缝无热影响区、切缝周围无飞溅区、切缝边缘平整、切缝垂直度好;根据切缝断面的特征,将切缝断面分成了三个区域,区域1(切缝上表面附近)、区域2(切缝中间区域)及区域3(切缝下表面附近),区域1的表面粗糙度约为8.037-14.621μm、区域2的表面粗糙度约为4.908-6.640μm、区域3的表面粗糙度约为6.344-7.108μm,由结果可知,三个区域的表面粗糙度差别较大,区域2的粗糙度最小,区域3次之,区域1的粗糙度最大;水导激光切缝崩边尺寸约为42μm,与传统切割崩边尺寸(70μm)比较,减小了40%。
[Abstract]:Silicon wafer is a common semiconductor material. The traditional silicon wafer cutting method is high speed diamond wafer contact cutting. As a non-contact cutting method, laser cutting can effectively control the defects caused by non-uniform stress in contact. Firstly, according to the principle of motion and optical system of double-mirror laser cutting head, the special cutting head for silicon wafer cutting is designed by using solidworks software. The main design contents include optical fiber connection module, collimation module and robot connection module. The cutting range of the cutting head is 200mm 脳 200mm, and the cutting precision is 卤0.05mm. Through the verification of silicon wafer cutting, the design of double mirror laser cutting head meets the requirements of design and production. The picosecond laser cutting test of silicon wafer was carried out by using the designed double mirror laser cutting head. The cutting and implicit crystal cutting experiments were carried out by changing the cutting parameters such as the output power of picosecond laser, the laser pulse frequency and the cutting speed. The results show that the notch width and depth increase with the increase of laser output power, increase with the increase of laser pulse frequency, and decrease with the increase of cutting speed. The slagging height and spatter width increase with the increase of laser output power, increase with the increase of laser pulse frequency and decrease with the increase of cutting speed. The optimum technological parameters are as follows: laser power 30W, cutting speed 100mm / s, laser pulse frequency 40kHz. Through scanning electron microscope (SEM) and energy dispersive analyzer (EDS) to analyze the groove under the optimum technological parameters, the results show that although the energy density is high in the process of picosecond laser cutting, there is almost no oxidation around the notch. The physical and chemical properties of the material around the groove are guaranteed. The experimental results show that the optimum cutting parameters are laser output power of 0.88 W, laser pulse frequency of 80 kHz and cutting speed of 300 mm / s. Compared with the conventional slit size of silicon wafer (70 渭 m), the dimension (40 渭 m) of cryptocrystalline cutting is obviously reduced. Compared with the size (42 渭 m) of the water-conducting laser cutting of silicon wafers, the size of edge breaking is reduced by about 5%. In order to compare the effect of laser cutting method on the cutting quality of silicon wafer, the water conduction laser cutting method was used to cut silicon wafer. The optimum cutting parameters are water pressure 13MPa, power 2W, cutting speed 500mm / min. The optimum parameters of water-conducting laser cutting are water pressure 13MPa, power 2W, cutting speed 200mm / min. There is no splash area around the joint, the edge of the joint is flat and the seam is perpendicular. According to the characteristics of the section of the cutting joint, the section is divided into three regions. Region 1 (near the top surface of the notch), region 2 (middle area of the notch) and region 3 (near the surface of the cut joint), the surface roughness of region 1 is about 8.037-14.621 渭 m, the surface roughness of region 2 is about 4.908-6.640 渭 m, the surface roughness of region 3 is about 6.344-7.108 渭 m, the results show that the surface roughness of region 1 is about 8.037-14.621 渭 m, and that of region 2 is about 6.344-7.108 渭 m. The surface roughness of the three regions is different greatly, the roughness of region 2 is the smallest, the roughness of region 3 is the second, and the roughness of region 1 is the largest, and the size of water conduction laser cutting seam is about 42 渭 m, which is reduced by 40% compared with the traditional cutting dimension (70 渭 m).
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN305.1

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