一、光刻膠的制造流程
1、準備基質
在涂布光阻劑之前,硅片一般要進行處理,需要經過脫水烘培蒸發掉硅片表面的水分,并涂上用來增加光刻膠與硅片表面附著能力(li)的(de)化合物(wu)。
2、涂布光阻劑
將(jiang)硅(gui)(gui)片(pian)(pian)(pian)放在一個(ge)平整的(de)金屬托盤上(shang),托盤內有小孔與真空管相(xiang)連,硅(gui)(gui)片(pian)(pian)(pian)就被吸在托盤上(shang),這樣硅(gui)(gui)片(pian)(pian)(pian)就可(ke)以(yi)與托盤一起旋(xuan)轉。涂膠(jiao)工藝一般分為三個(ge)步驟:1)將(jiang)光(guang)刻(ke)膠(jiao)溶液噴灑倒硅(gui)(gui)片(pian)(pian)(pian)表面;2)加速(su)旋(xuan)轉托盤(硅(gui)(gui)片(pian)(pian)(pian)),直到達到所需的(de)旋(xuan)轉速(su)度;3)達到所需的(de)旋(xuan)轉速(su)度之后(hou),保持一定時間的(de)旋(xuan)轉。由于硅(gui)(gui)片(pian)(pian)(pian)表面的(de)光(guang)刻(ke)膠(jiao)是(shi)借旋(xuan)轉時的(de)離(li)心力作(zuo)用向著硅(gui)(gui)片(pian)(pian)(pian)外圍移(yi)動,故涂膠(jiao)也可(ke)稱做甩膠(jiao)。經過(guo)甩膠(jiao)之后(hou),留(liu)在硅(gui)(gui)片(pian)(pian)(pian)表面的(de)光(guang)刻(ke)膠(jiao)不(bu)足原有的(de)1%。
3、軟烘干
也稱前烘。在(zai)(zai)液(ye)態(tai)(tai)的光(guang)刻膠(jiao)(jiao)中,溶(rong)劑成(cheng)分占65%-85%,甩膠(jiao)(jiao)之后雖然液(ye)態(tai)(tai)的光(guang)刻膠(jiao)(jiao)已經成(cheng)為固態(tai)(tai)的薄(bo)(bo)膜,但仍(reng)有(you)10%-30%的溶(rong)劑,容易(yi)玷(dian)污灰塵。通過(guo)在(zai)(zai)較高溫度(du)(du)下進行烘培,可(ke)(ke)以(yi)使溶(rong)劑從光(guang)刻膠(jiao)(jiao)中揮發(fa)出來(前烘后溶(rong)劑含量降至5%左右),從而(er)降低了灰塵的玷(dian)污。同(tong)時還可(ke)(ke)以(yi)減(jian)輕因高速旋(xuan)轉形成(cheng)的薄(bo)(bo)膜應力,從而(er)提高光(guang)刻膠(jiao)(jiao)的附著(zhu)性(xing)。在(zai)(zai)前烘過(guo)程(cheng)中,由(you)于溶(rong)劑揮發(fa),光(guang)刻膠(jiao)(jiao)厚度(du)(du)也會(hui)減(jian)薄(bo)(bo),一般減(jian)薄(bo)(bo)的幅度(du)(du)為10%-20%左右。
4、曝光
曝(pu)光(guang)(guang)(guang)(guang)(guang)過程(cheng)中(zhong),光(guang)(guang)(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)中(zhong)的感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)劑(ji)發生(sheng)光(guang)(guang)(guang)(guang)(guang)化(hua)(hua)學反應,從(cong)而使(shi)正膠(jiao)(jiao)的感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)區、負膠(jiao)(jiao)的非感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)區能夠溶(rong)(rong)解(jie)于顯影液中(zhong)。正性光(guang)(guang)(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)中(zhong)的感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)劑(ji)DQ發生(sheng)光(guang)(guang)(guang)(guang)(guang)化(hua)(hua)學反應,變為乙(yi)烯(xi)酮,進一步水(shui)解(jie)為茚并羧酸(suan),羧酸(suan)對堿性溶(rong)(rong)劑(ji)的溶(rong)(rong)解(jie)度(du)比未感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)的感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)劑(ji)高(gao)出約100倍(bei),同(tong)時還會促進酚醛樹脂的溶(rong)(rong)解(jie)。于是利用感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)與未感(gan)(gan)(gan)光(guang)(guang)(guang)(guang)(guang)的光(guang)(guang)(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)對堿性溶(rong)(rong)劑(ji)的不同(tong)溶(rong)(rong)解(jie)度(du),就可以進行掩(yan)膜圖(tu)形的轉移。
5、顯影
經顯影(ying),正膠(jiao)(jiao)的感光(guang)(guang)(guang)區(qu)、負膠(jiao)(jiao)的非感光(guang)(guang)(guang)區(qu)溶(rong)解于顯影(ying)液中,曝光(guang)(guang)(guang)后在光(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)層中的潛在圖形,顯影(ying)后便顯現出(chu)來,在光(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)上形成三位圖形。為(wei)了提高分辨率,幾乎(hu)每一(yi)種光(guang)(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)都有專(zhuan)門的顯影(ying)液,以(yi)保證高質量(liang)的顯影(ying)效(xiao)果(guo)。
6、硬烘干
也稱堅膜(mo)。顯(xian)影(ying)后,硅片(pian)(pian)還要經(jing)過一個高(gao)(gao)溫(wen)(wen)處理過程,主要作用是除(chu)去(qu)光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)中剩(sheng)余(yu)的(de)溶劑,增強光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)對硅片(pian)(pian)表(biao)面的(de)附著(zhu)力(li)(li)(li),同時提高(gao)(gao)光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)在刻(ke)(ke)蝕和離子注入過程中的(de)抗蝕性和保護能力(li)(li)(li)。在此溫(wen)(wen)度(du)下,光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)將軟化(hua)(hua),形成類(lei)似玻璃體在高(gao)(gao)溫(wen)(wen)下的(de)熔融狀態。這會使光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)表(biao)面在表(biao)面張力(li)(li)(li)作用下圓滑化(hua)(hua),并使光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)層中的(de)缺(que)陷(xian)(如針(zhen)孔)因此減少,借(jie)此修正光(guang)(guang)刻(ke)(ke)膠(jiao)(jiao)圖形的(de)邊(bian)緣輪(lun)廓。
7、刻(腐)蝕或離子注入
8、去膠
刻蝕或離子(zi)注入之后,已經(jing)不(bu)再需要光(guang)(guang)(guang)(guang)刻膠(jiao)(jiao)(jiao)(jiao)作保(bao)護層,可以將(jiang)其除(chu)去(qu)(qu)(qu),稱(cheng)為(wei)去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao),分為(wei)濕(shi)法去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao)和干法去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao),其中濕(shi)法去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao)又分有(you)機溶(rong)(rong)劑(ji)去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao)和無(wu)機溶(rong)(rong)劑(ji)去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao)。有(you)機溶(rong)(rong)劑(ji)去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao),主要是(shi)使光(guang)(guang)(guang)(guang)刻膠(jiao)(jiao)(jiao)(jiao)溶(rong)(rong)于(yu)有(you)機溶(rong)(rong)劑(ji)而(er)除(chu)去(qu)(qu)(qu);無(wu)機溶(rong)(rong)劑(ji)去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao)則是(shi)利用(yong)光(guang)(guang)(guang)(guang)刻膠(jiao)(jiao)(jiao)(jiao)本(ben)身也是(shi)有(you)機物的(de)特點,通過(guo)一些無(wu)機溶(rong)(rong)劑(ji),將(jiang)光(guang)(guang)(guang)(guang)刻膠(jiao)(jiao)(jiao)(jiao)中的(de)碳元素氧(yang)化為(wei)二氧(yang)化碳而(er)將(jiang)其除(chu)去(qu)(qu)(qu)。干法去(qu)(qu)(qu)膠(jiao)(jiao)(jiao)(jiao),則是(shi)用(yong)等離子(zi)體將(jiang)光(guang)(guang)(guang)(guang)刻膠(jiao)(jiao)(jiao)(jiao)剝除(chu)。
二、光刻膠制備方法
光刻膠制(zhi)作是一(yi)項(xiang)制(zhi)作印刷出版品,電子元件和(he)芯(xin)片基板等(deng)精密細節的任(ren)務,它(ta)可(ke)以使產品品質更(geng)好、速(su)度(du)更(geng)快以及圖案更(geng)清晰且(qie)可(ke)重(zhong)復性高。下面將圍繞光刻膠來介紹一(yi)下其(qi)制(zhi)作的步驟。
1、首先,需(xu)要(yao)準(zhun)備(bei)一些基本材料,包括光(guang)刻油(you)墨、總溶劑(ji)、無水乙(yi)醇(chun)、光(guang)刻膠(jiao)片(pian)(pian)以及洗版片(pian)(pian)等(deng)。具(ju)體材料需(xu)要(yao)根據不同情況選擇,常見的光(guang)刻膠(jiao)片(pian)(pian)有PE片(pian)(pian)、PVC片(pian)(pian)和PC基片(pian)(pian)等(deng)。
2、接著,熔(rong)化光(guang)(guang)刻(ke)(ke)油墨。將所需的(de)光(guang)(guang)刻(ke)(ke)油墨投入(ru)熔(rong)鍋,加入(ru)總(zong)溶劑和無水乙醇,熔(rong)化攪拌至光(guang)(guang)刻(ke)(ke)油墨充分溶解(jie),并維持(chi)高溫狀態10-20分鐘,熔(rong)化溫度一般達(da)到200℃左右。
3、然(ran)后,就是制作光(guang)刻膠。將(jiang)混合物倒入(ru)特定的(de)(de)烘(hong)箱(xiang),使其能夠(gou)容納光(guang)刻片(pian),加上少量脫(tuo)模(mo)劑,將(jiang)光(guang)刻膠片(pian)在(zai)烘(hong)箱(xiang)內暴露在(zai)200°高溫的(de)(de)空氣中(zhong),保持1小(xiao)時左(zuo)右,至膠片(pian)變軟且完全吸收光(guang)刻油墨(mo),再(zai)放入(ru)冷(leng)卻抽風箱(xiang)中(zhong)冷(leng)卻1-2個小(xiao)時。
4、最后,就是(shi)洗(xi)版(ban)。首(shou)先將冷卻的(de)(de)光刻膠片(pian)和(he)實(shi)物模板(ban)放置(zhi)在洗(xi)版(ban)槽中(zhong),用(yong)洗(xi)滌(di)劑洗(xi)滌(di)洗(xi)版(ban)片(pian),保(bao)證洗(xi)版(ban)片(pian)覆(fu)蓋牢固,然后用(yong)抽(chou)空(kong)裝(zhuang)置(zhi)抽(chou)空(kong)空(kong)氣(qi)中(zhong)的(de)(de)殘留毛刺,最后,將光刻膠片(pian)及模板(ban)取出。
總之,制作光刻膠有收集材(cai)料、熔化光刻(ke)油墨、制作光刻(ke)膠、以及(ji)(ji)洗版等四個步驟。它涉(she)及(ji)(ji)有材(cai)料以及(ji)(ji)技術等方面(mian),制作完成之后,可(ke)以在制作印刷出版品、電(dian)子元(yuan)件和芯片基板等精密細節的任務中大顯身手。