用于温度补偿型声表面波滤波器温补层的化学机械抛光工艺  

Chemical Mechanical Polishing Process for Temperature Compensation Layer of TC-SAW Filter

作　　者：冯志博 李湃 袁燕 史向龙 于海洋 孟腾飞 Feng Zhibo;Li Pai;Yuan Yan;Shi Xianglong;Yu Haiyang;Meng Tengfei(Beijing Aerospace Microelectronics Technology Co.,Ltd.,Beijing 100854,China)

机构地区：[1]北京航天微电科技有限公司,北京100854

出　　处：《微纳电子技术》2023年第2期320-326,共7页Micronanoelectronic Technology

摘　　要：在制备温度补偿型声表面波(TC-SAW)滤波器温补层工艺过程中,温补层薄膜的厚度控制、膜层质量控制和膜厚不均匀性(NU)控制十分重要。对TC-SAW滤波器晶圆的温补层的化学机械抛光(CMP)工艺进行了研究,探讨了不同晶圆背压和保持环压力的比值、抛光头转速和抛光盘转速的比值等对温补层的影响,进一步优化工艺参数,并研究了CMP对温补层表面粗糙度的影响。结果表明:采用优化后的工艺参数,即晶圆背压与保持环压力比值约为1.46(晶圆背压为350 g/cm^(3),保持环压力为240 g/cm^(3))、抛光头转速为93 r/min、抛光盘转速为87 r/min时,可以获得厚度稳定、表面均匀性良好、粗糙度为0.4 nm的膜层。最后将TC-SAW滤波器晶圆温补层进行化学机械抛光,得到膜厚为605.4 nm,总厚度偏差(TTV)为62.06 nm,NU为2.54%的温补层表面,最终得到滤波器的温漂系数为-1.478×10^(-5)/℃,可以满足设计要求,提高了滤波器的合格率。In the preparation process of the temperature compensation layer of temperature compensated surface acoustic wave(TC-SAW)filter,it is very important to control the thickness of the temperature compensation layer film,film quality and film thickness non-uniformity(NU).The chemical mechanical polishing(CMP)process of the temperature compensation layer of the TC-SAW filter wafer was studied,the effects of different ratios of wafer back pressure and retaining ring pressure,different ratios of polishing head rotatio-nal speed and polishing plate rotational speed on the temperature compensation layer were discussed.The process parameters were further optimized,and the effect of CMP on the surface roughness of the temperature compensation layer was investigated.The results show that using the optimized process parameters,i.e.,the ratio of wafer back pressure and retaining ring pressure is about 1.46(the wafer back pressure is 350 g/cm^(3),the holding ring pressure is 240 g/cm^(3)),the polishing head rotational speed is 93 r/min,and the polishing plate rotational speed is 87 r/min,the film with stable thickness,good surface uniformity and roughness of 0.4 nm can be obtained.Finally,the temperature compensation layer of the TC-SAW filter wafer was polished.The temperature compensation layer surface with a film thickness of 605.4 nm,a total thickness variation(TTV)of 62.06 nm,a NU of 2.54%can be obtained,and the temperature drift coefficient of the filter is-1.478×10^(-5)/℃,which can meet the design requirements and improve the qualification rate of the filter.

关 键 词：化学机械抛光(CMP) 声表面波滤波器 温补层 膜厚不均匀性 温漂系数 

分 类 号：TN305.2[电子电信—物理电子学]