硅片(pian)背(bei)面(mian)(mian)(mian)減(jian)薄(bo)是(shi)一步重(zhong)要的(de)(de)(de)硅片(pian)制造工(gong)藝(yi)，目的(de)(de)(de)是(shi)去除硅片(pian)背(bei)面(mian)(mian)(mian)多余材料，以(yi)有效(xiao)減(jian)小硅片(pian)封(feng)裝(zhuang)體積，降(jiang)低(di)熱阻，提(ti)高(gao)器件(jian)的(de)(de)(de)散(san)熱性(xing)(xing)(xing)能，降(jiang)低(di)封(feng)裝(zhuang)后芯(xin)(xin)片(pian)因受熱不均而(er)(er)開裂(lie)的(de)(de)(de)風險，提(ti)高(gao)產(chan)品可靠(kao)性(xing)(xing)(xing)；同時，減(jian)薄(bo)后的(de)(de)(de)芯(xin)(xin)片(pian)機械性(xing)(xing)(xing)能與電氣性(xing)(xing)(xing)能也得到(dao)顯著提(ti)高(gao)。硅片(pian)背(bei)面(mian)(mian)(mian)減(jian)薄(bo)技術(shu)有很(hen)多種，如(ru)磨(mo)(mo)削、拋光、干式拋光、電化(hua)(hua)(hua)學(xue)腐(fu)(fu)蝕(shi)(shi)、濕(shi)法腐(fu)(fu)蝕(shi)(shi)、等離(li)子(zi)輔助化(hua)(hua)(hua)學(xue)腐(fu)(fu)蝕(shi)(shi)和(he)常(chang)壓等離(li)子(zi)腐(fu)(fu)蝕(shi)(shi)等。其中硅片(pian)磨(mo)(mo)削減(jian)薄(bo)技術(shu)是(shi)一種效(xiao)率(lv)高(gao)、成本(ben)較低(di)的(de)(de)(de)減(jian)薄(bo)技術(shu)，已得到(dao)廣泛應用。該技術(shu)通過砂(sha)輪(lun)在硅片(pian)表面(mian)(mian)(mian)旋轉施壓、損傷(shang)、破(po)裂(lie)、移(yi)除而(er)(er)實(shi)現(xian)硅片(pian)減(jian)薄(bo)。工(gong)藝(yi)中不可避(bi)免引入損傷(shang)，降(jiang)低(di)器件(jian)可靠(kao)性(xing)(xing)(xing)和(he)穩定(ding)性(xing)(xing)(xing)。拋光工(gong)藝(yi)采用硅片(pian)與拋光頭(tou)之間相對(dui)運動來平(ping)坦(tan)化(hua)(hua)(hua)硅片(pian)表面(mian)(mian)(mian)，在硅片(pian)和(he)拋光頭(tou)之間有磨(mo)(mo)料；濕(shi)法化(hua)(hua)(hua)學(xue)腐(fu)(fu)蝕(shi)(shi)是(shi)一種通過腐(fu)(fu)蝕(shi)(shi)液與硅片(pian)發生化(hua)(hua)(hua)學(xue)反(fan)應實(shi)現(xian)硅片(pian)減(jian)薄(bo)的(de)(de)(de)工(gong)藝(yi)技術(shu)，常(chang)用的(de)(de)(de)腐(fu)(fu)蝕(shi)(shi)液有酸(suan)(suan)性(xing)(xing)(xing)腐(fu)(fu)蝕(shi)(shi)液（如(ru)硝酸(suan)(suan)、冰乙酸(suan)(suan)與氫氟酸(suan)(suan)）和(he)堿性(xing)(xing)(xing)腐(fu)(fu)蝕(shi)(shi)（如(ru)KOH溶液［1］）。

　　本文以(yi)15．24cm（6英寸）硅片(pian)(pian)背面減薄(bo)(bo)為(wei)例，通過對經過磨(mo)削(xue)、磨(mo)削(xue)后(hou)(hou)拋光與磨(mo)削(xue)后(hou)(hou)濕法腐蝕工藝后(hou)(hou)硅片(pian)(pian)的(de)損傷(shang)、表面粗糙(cao)度與翹曲度的(de)分(fen)析(xi)，優化硅片(pian)(pian)背面減薄(bo)(bo)技術。

　　取4片(pian)6英(ying)(ying)寸單(dan)晶硅片(pian)，硅片(pian)厚(hou)(hou)度(du)為(wei)(wei)675μm，正面貼保(bao)護膜，保(bao)護膜厚(hou)(hou)度(du)為(wei)(wei)140μm；采(cai)用(yong)方(fang)(fang)達(da)(da)科技單(dan)片(pian)研(yan)(yan)磨(mo)機對硅片(pian)進行(xing)磨(mo)削減薄(bo)(bo)加(jia)工(gong)，加(jia)工(gong)選用(yong)325＃－DISCO砂(sha)(sha)輪(lun)，砂(sha)(sha)輪(lun)粒度(du)為(wei)(wei)40～60μm，將4片(pian)6英(ying)(ying)寸硅片(pian)減薄(bo)(bo)140μm至535μm，取出其中1個樣(yang)品，編號(hao)為(wei)(wei)1＃；接著采(cai)用(yong)方(fang)(fang)達(da)(da)單(dan)面研(yan)(yan)磨(mo)機對余下3個樣(yang)品進行(xing)精磨(mo)削加(jia)工(gong)，加(jia)工(gong)選用(yong)2000＃－DISCO砂(sha)(sha)輪(lun)，砂(sha)(sha)輪(lun)粒度(du)為(wei)(wei)4～6μm，去除硅片(pian)厚(hou)(hou)度(du)為(wei)(wei)30μm，取出其中1個樣(yang)品，編號(hao)為(wei)(wei)2＃；對余下的兩個樣(yang)品，一(yi)個采(cai)用(yong)方(fang)(fang)達(da)(da)科技單(dan)面拋光(guang)(guang)機進行(xing)化學機械拋光(guang)(guang)40min，編號(hao)為(wei)(wei)3＃，另一(yi)個用(yong)濕法化學腐(fu)(fu)蝕方(fang)(fang)式(shi)減薄(bo)(bo)，腐(fu)(fu)蝕時間5min，編號(hao)為(wei)(wei)4＃。濕法腐(fu)(fu)蝕采(cai)用(yong)硝酸、冰乙酸和氫(qing)氟(fu)酸混合液腐(fu)(fu)蝕液，體積(ji)比為(wei)(wei)硝酸∶冰乙酸∶氫(qing)氟(fu)酸＝5∶4∶1，反應(ying)原(yuan)理(li)如(ru)下［2］：

　　完成(cheng)上述減薄工藝后，去除(chu)樣(yang)品(pin)(pin)正面(mian)保(bao)護膜，清洗，然(ran)后采用(yong)Mitotuyo厚度(du)測(ce)試儀(yi)測(ce)試樣(yang)品(pin)(pin)厚度(du)，用(yong)翹(qiao)曲(qu)度(du)測(ce)試儀(yi)測(ce)試樣(yang)品(pin)(pin)翹(qiao)曲(qu)度(du)，采用(yong)FEG450掃描電子顯(xian)(xian)微鏡觀察樣(yang)品(pin)(pin)表(biao)面(mian)和截(jie)面(mian)形(xing)貌，用(yong)原子力(li)顯(xian)(xian)微鏡測(ce)試樣(yang)品(pin)(pin)粗糙度(du)。

　　2．1表面形貌分析
　　圖2是減薄后樣(yang)品表(biao)面掃描電子形貌圖（SEM）。由(you)圖可見(jian)，1＃樣(yang)品表(biao)面粗糙(cao)、起伏(fu)大，存(cun)在凸起與(yu)(yu)凹坑；2＃樣(yang)品表(biao)面存(cun)在大量細(xi)小劃痕(hen)。原子力(li)顯微鏡測(ce)試得出1＃樣(yang)品與(yu)(yu)2＃表(biao)面粗糙(cao)度Ra分別為0．15和0．016μm。

　　單晶硅材料的原子在晶體內部按照金剛石結構周期性排列，硅片背面磨削減薄是一種物理損傷工藝，砂輪的磨削會破壞硅原子內部的周期性排列順序，在硅片表面產生機械損傷。對比圖2（a）與圖2（b）可知，樣品表面形貌和表面粗糙度與研磨所用砂輪有關，砂輪粒度越小，硅片表面越平整，粗糙度越小。
　　圖2（c）和圖2（d）分別(bie)為(wei)3＃與(yu)4＃樣(yang)(yang)(yang)品(pin)表(biao)(biao)面形(xing)貌(mao)圖，對(dui)比兩圖可(ke)見，化學(xue)(xue)機械(xie)拋(pao)光(guang)后樣(yang)(yang)(yang)品(pin)表(biao)(biao)面平整，沒有(you)磨(mo)削(xue)劃(hua)痕(hen)，濕(shi)(shi)法腐蝕(shi)(shi)(shi)(shi)后樣(yang)(yang)(yang)品(pin)表(biao)(biao)面依(yi)然可(ke)見砂輪磨(mo)削(xue)留下的劃(hua)痕(hen)。3＃與(yu)4＃樣(yang)(yang)(yang)品(pin)表(biao)(biao)面粗(cu)糙度Ra分別(bie)為(wei)0．001和0．008μm。化學(xue)(xue)機械(xie)拋(pao)光(guang)工(gong)(gong)藝(yi)是一(yi)(yi)種全(quan)局性平坦化工(gong)(gong)藝(yi)，由上(shang)述結果可(ke)知，拋(pao)光(guang)工(gong)(gong)藝(yi)有(you)效(xiao)地改(gai)善(shan)了硅片表(biao)(biao)面形(xing)貌(mao)；腐蝕(shi)(shi)(shi)(shi)工(gong)(gong)藝(yi)后樣(yang)(yang)(yang)品(pin)表(biao)(biao)面粗(cu)糙度降低，結合(he)酸性濕(shi)(shi)法腐蝕(shi)(shi)(shi)(shi)工(gong)(gong)藝(yi)是一(yi)(yi)種各向(xiang)同性腐蝕(shi)(shi)(shi)(shi)工(gong)(gong)藝(yi)［3］，樣(yang)(yang)(yang)品(pin)表(biao)(biao)面損傷與(yu)凸起部分被優先腐蝕(shi)(shi)(shi)(shi)，可(ke)見濕(shi)(shi)法腐蝕(shi)(shi)(shi)(shi)可(ke)改(gai)善(shan)硅片表(biao)(biao)面形(xing)貌(mao)。4個樣(yang)(yang)(yang)品(pin)表(biao)(biao)面粗(cu)糙度Ra見表(biao)(biao)2所示。

　　2．2截面形貌分析
　　圖3為(wei)樣(yang)品截面形貌圖（SEM），可(ke)見1＃樣(yang)品截面粗糙(cao)，截面存在裂紋(wen)，2＃樣(yang)品截面平直，有微裂紋(wen)。由圖可(ke)知，樣(yang)品截面損傷層厚度分(fen)別為(wei)5．382與1．115μm。

　　硅片磨削減薄是一種物理性損傷工藝，根據Hadamovsky提出的損傷層模型［4］，機械研磨減薄工藝后，基體硅之上存在著損傷層，損傷層自上而下分為多層結構。結合上述實驗可知，損傷層厚度與研磨硅片砂輪粒度有關，砂輪粒度越大，磨削產生的損傷層越大，硅片表面越粗糙。3＃與4＃樣品截面圖如圖3（c）與圖3（d）所示，樣品截面無損傷層，結合上文可知，拋光工藝和濕法腐蝕工藝去除了樣品表面的機械損傷，減薄后樣品厚度以及表面損傷層厚度如表3所示。表3中還列出了樣品的翹曲度，由表中可知，樣品翹曲度與表面損傷層厚度相關，如圖4所示，損傷層厚度越大，翹曲度也越大。硅片表面的機械損傷破壞了硅片晶體結構，降低硅片強度，增大硅片在傳遞過程中碎片率，影響后續工藝的可靠性與穩定性，降低了產品成品率。拋光工藝和濕法腐蝕不僅可以去除硅片表面損傷層，還降低了硅片翹曲度，有效提高減薄后硅片質量，這對提高生產線成品率，拓寬元器件使用條件，提高元器件使用性能，延長使用壽命等都具有極其重要的意義。

　　硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)背面(mian)(mian)(mian)(mian)機械(xie)研磨減(jian)(jian)薄(bo)(bo)是一種物理損(sun)(sun)傷(shang)(shang)工藝(yi)，減(jian)(jian)薄(bo)(bo)會在(zai)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)引入機械(xie)損(sun)(sun)傷(shang)(shang)。文中對(dui)比分(fen)析(xi)(xi)了粗磨、精磨、拋(pao)光(guang)(guang)(guang)和濕法(fa)(fa)(fa)(fa)腐(fu)(fu)蝕工藝(yi)后硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)與(yu)截面(mian)(mian)(mian)(mian)形(xing)(xing)貌，并(bing)且(qie)測試了硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)厚(hou)(hou)度(du)(du)(du)(du)、粗糙(cao)(cao)度(du)(du)(du)(du)和翹(qiao)曲(qu)度(du)(du)(du)(du)，結合(he)理論(lun)分(fen)析(xi)(xi)，得到結論(lun)如下(xia)：機械(xie)研磨減(jian)(jian)薄(bo)(bo)工藝(yi)中硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)形(xing)(xing)貌和損(sun)(sun)傷(shang)(shang)層(ceng)厚(hou)(hou)度(du)(du)(du)(du)和研磨減(jian)(jian)薄(bo)(bo)砂輪粒度(du)(du)(du)(du)有關，砂輪粒度(du)(du)(du)(du)越(yue)大(da)，硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)越(yue)不(bu)平整，粗糙(cao)(cao)度(du)(du)(du)(du)也(ye)越(yue)大(da)，損(sun)(sun)傷(shang)(shang)層(ceng)厚(hou)(hou)度(du)(du)(du)(du)越(yue)大(da)。采用粗磨與(yu)精磨結合(he)減(jian)(jian)薄(bo)(bo)的(de)方法(fa)(fa)(fa)(fa)，可(ke)以(yi)改善(shan)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)形(xing)(xing)貌，降低硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)損(sun)(sun)傷(shang)(shang)層(ceng)厚(hou)(hou)度(du)(du)(du)(du)；濕法(fa)(fa)(fa)(fa)腐(fu)(fu)蝕與(yu)拋(pao)光(guang)(guang)(guang)工藝(yi)可(ke)以(yi)改善(shan)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)形(xing)(xing)貌，去除硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)減(jian)(jian)薄(bo)(bo)中產生的(de)機械(xie)損(sun)(sun)傷(shang)(shang)，拋(pao)光(guang)(guang)(guang)工藝(yi)可(ke)以(yi)得到粗糙(cao)(cao)度(du)(du)(du)(du)更低的(de)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)表(biao)(biao)面(mian)(mian)(mian)(mian)，速率較慢，濕法(fa)(fa)(fa)(fa)腐(fu)(fu)蝕工藝(yi)效率高(gao)，表(biao)(biao)面(mian)(mian)(mian)(mian)較粗糙(cao)(cao)；減(jian)(jian)薄(bo)(bo)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)的(de)翹(qiao)曲(qu)度(du)(du)(du)(du)與(yu)損(sun)(sun)傷(shang)(shang)層(ceng)厚(hou)(hou)度(du)(du)(du)(du)有關，損(sun)(sun)傷(shang)(shang)層(ceng)厚(hou)(hou)度(du)(du)(du)(du)越(yue)大(da)，硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)翹(qiao)曲(qu)度(du)(du)(du)(du)越(yue)大(da)。實(shi)際(ji)工藝(yi)中，結合(he)器件需求，可(ke)以(yi)采用先分(fen)段研磨，再拋(pao)光(guang)(guang)(guang)或濕法(fa)(fa)(fa)(fa)腐(fu)(fu)蝕的(de)方法(fa)(fa)(fa)(fa)，得到高(gao)質量的(de)減(jian)(jian)薄(bo)(bo)硅(gui)(gui)(gui)(gui)(gui)片(pian)(pian)(pian)(pian)(pian)。