一、FPC 開料

        除部(bu)分材(cai)料以(yi)外(wai),柔(rou)(rou)性(xing)(xing)印制板所(suo)用的(de)(de)(de)(de)材(cai)料基(ji)本都是卷(juan)狀的(de)(de)(de)(de)。由于并不是所(suo)有(you)的(de)(de)(de)(de)工(gong)(gong)(gong)序(xu)都一定要用卷(juan)帶工(gong)(gong)(gong)藝(yi)進行(xing)加工(gong)(gong)(gong),有(you)些工(gong)(gong)(gong)序(xu)必須裁成片(pian)狀才能加工(gong)(gong)(gong),如(ru)雙面柔(rou)(rou)性(xing)(xing)印制板的(de)(de)(de)(de)金屬化孔(kong)的(de)(de)(de)(de)鉆孔(kong),目前只能以(yi)片(pian)狀形式進行(xing)鉆孔(kong),所(suo)以(yi)雙面柔(rou)(rou)性(xing)(xing)印制板第一道(dao)工(gong)(gong)(gong)序(xu)就(jiu)是開料。

       柔性覆(fu)銅(tong)箔層壓板對外(wai)力的(de)承受(shou)(shou)能(neng)力極差,很(hen)容易(yi)受(shou)(shou)傷(shang)。如果在開料(liao)時(shi)受(shou)(shou)到損傷(shang)將對以后各工序(xu)的(de)合格率產生嚴重(zhong)影(ying)響。因此(ci),即使看(kan)上去是(shi)十分簡(jian)單的(de)開料(liao),為了(le)保證(zheng)材料(liao)的(de)品質,也必須給予足夠(gou)重(zhong)視。如果量比較少(shao),可使用(yong)(yong)手工剪切機或滾刀切斷器,大批量,可用(yong)(yong)自動剪切機。

       無論(lun)是單面、雙面銅箔層壓板還是覆蓋膜,開料(liao)尺(chi)寸(cun)的(de)(de)(de)精度可(ke)達到±0.33。開料(liao)的(de)(de)(de)可(ke)靠性高,開好(hao)的(de)(de)(de)材料(liao)自動(dong)整齊(qi)疊放(fang),在(zai)出口處(chu)不需要人員(yuan)進行收料(liao)。能把對(dui)材料(liao)的(de)(de)(de)損傷控制在(zai)最小限度內,利(li)用送(song)料(liao)輥(gun)尺(chi)寸(cun)的(de)(de)(de)變化,材料(liao)幾乎沒(mei)有皺折、傷痕發生。而且最新的(de)(de)(de)裝(zhuang)置也能對(dui)卷(juan)帶工(gong)藝(yi)蝕(shi)刻后(hou)(hou)的(de)(de)(de)柔性印制板進行自動(dong)裁切,利(li)用光學傳感器(qi)可(ke)以(yi)檢出腐(fu)蝕(shi)定位圖形,進行自動(dong)開料(liao)定位,開料(liao)精度達0.3mm,但(dan)不能把這種開料(liao)的(de)(de)(de)邊框作為以(yi)后(hou)(hou)工(gong)序(xu)的(de)(de)(de)定位。

二

FPC 鉆導通孔

       柔性(xing)印制(zhi)(zhi)板的(de)通孔(kong)(kong)(kong)(kong)與剛(gang)性(xing)印制(zhi)(zhi)板一樣也可以用數控鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong),但不適用于(yu)卷(juan)帶雙面(mian)金屬化孔(kong)(kong)(kong)(kong)電路的(de)孔(kong)(kong)(kong)(kong)加工(gong)。隨著電路圖形(xing)的(de)高密度(du)化和(he)金屬化孔(kong)(kong)(kong)(kong)的(de)小孔(kong)(kong)(kong)(kong)徑化,加上數控鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)的(de)孔(kong)(kong)(kong)(kong)徑有一定界(jie)限,現在許多新(xin)的(de)鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)技術已付(fu)實際應(ying)用。這些(xie)新(xin)的(de)鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)技術包括等(deng)離子體蝕孔(kong)(kong)(kong)(kong)、激光鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)、微(wei)小孔(kong)(kong)(kong)(kong)徑的(de)沖(chong)孔(kong)(kong)(kong)(kong)、化學蝕孔(kong)(kong)(kong)(kong)等(deng),這些(xie)鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)技術比數控鉆(zhan)(zhan)孔(kong)(kong)(kong)(kong)更容易滿(man)足卷(juan)帶工(gong)藝的(de)成(cheng)孔(kong)(kong)(kong)(kong)要求(qiu)。

       柔性(xing)印制(zhi)板的(de)通孔(kong)(kong)與剛性(xing)印制(zhi)板一(yi)樣也可(ke)以(yi)用數(shu)控鉆孔(kong)(kong),但不適用于卷(juan)帶(dai)雙面金屬(shu)化孔(kong)(kong)電路(lu)的(de)孔(kong)(kong)加工。隨著電路(lu)圖形(xing)的(de)高密度化和金屬(shu)化孔(kong)(kong)的(de)小孔(kong)(kong)徑化,加上(shang)數(shu)控鉆孔(kong)(kong)的(de)孔(kong)(kong)徑有一(yi)定界限,現在(zai)許多新的(de)鉆孔(kong)(kong)技(ji)術已付(fu)實際應用。這(zhe)些新的(de)鉆孔(kong)(kong)技(ji)術包括(kuo)等離(li)子(zi)體(ti)蝕孔(kong)(kong)、激(ji)光鉆孔(kong)(kong)、微小孔(kong)(kong)徑的(de)沖孔(kong)(kong)、化學(xue)蝕孔(kong)(kong)等,這(zhe)些鉆孔(kong)(kong)技(ji)術比數(shu)控鉆孔(kong)(kong)更容易滿足卷(juan)帶(dai)工藝的(de)成孔(kong)(kong)要求(qiu)。

01

數控鉆孔

       雙面柔(rou)(rou)(rou)性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)中通的鉆(zhan)(zhan)(zhan)孔(kong)(kong)現(xian)在大部分仍然是用(yong)數控(kong)鉆(zhan)(zhan)(zhan)床鉆(zhan)(zhan)(zhan)孔(kong)(kong),數控(kong)鉆(zhan)(zhan)(zhan)床與剛性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)使用(yong)的數控(kong)鉆(zhan)(zhan)(zhan)床基本(ben)上(shang)相(xiang)同,但鉆(zhan)(zhan)(zhan)孔(kong)(kong)的條件有所不同。由于柔(rou)(rou)(rou)性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)很薄,能夠把多片(pian)重疊(die)鉆(zhan)(zhan)(zhan)孔(kong)(kong),如果鉆(zhan)(zhan)(zhan)孔(kong)(kong)條件良好的話可(ke)以(yi)把 10～15 片(pian)重疊(die)在一起進行鉆(zhan)(zhan)(zhan)孔(kong)(kong)。墊板(ban)(ban)和蓋板(ban)(ban)可(ke)以(yi)使用(yong)紙(zhi)基酚醛層壓(ya)(ya)板(ban)(ban)或(huo)玻(bo)纖(xian)布環氧(yang)層壓(ya)(ya)板(ban)(ban),也(ye)完全(quan)可(ke)以(yi)使用(yong)厚(hou) 0.2～0.4mm 的鋁板(ban)(ban)。柔(rou)(rou)(rou)性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)所用(yong)鉆(zhan)(zhan)(zhan)頭(tou)(tou)市(shi)場上(shang)有售,剛性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)鉆(zhan)(zhan)(zhan)孔(kong)(kong)用(yong)的鉆(zhan)(zhan)(zhan)頭(tou)(tou)及銑(xian)外形(xing)用(yong)的銑(xian)刀(dao)也(ye)可(ke)以(yi)用(yong)于柔(rou)(rou)(rou)性(xing)印(yin)(yin)制(zhi)(zhi)(zhi)板(ban)(ban)。

       鉆孔(kong)、銑覆蓋膜和增強(qiang)板(ban)的外形等的加工條件(jian)基本(ben)相同,但由于柔性印(yin)制板(ban)材料所(suo)使用的膠黏劑柔軟(ruan),所(suo)以十分(fen)容易附著在鉆頭上,需要(yao)頻繁地對(dui)鉆頭狀態進行檢(jian)驗,而且要(yao)適當提高鉆頭的轉速。對(dui)于多(duo)層(ceng)柔性印(yin)制板(ban)或多(duo)層(ceng)剛柔印(yin)制板(ban)的鉆孔(kong)要(yao)特別(bie)細(xi)心。

02

沖孔

       沖(chong)微小孔(kong)(kong)(kong)徑不(bu)是(shi)新技術,作為大(da)批量(liang)生(sheng)(sheng)產已有使(shi)用(yong)。由于卷(juan)帶工藝(yi)是(shi)連續生(sheng)(sheng)產,利(li)(li)用(yong)沖(chong)孔(kong)(kong)(kong)來加工卷(juan)帶的(de)(de)通孔(kong)(kong)(kong)也有不(bu)少實例。但是(shi)批量(liang)沖(chong)孔(kong)(kong)(kong)技術僅限于沖(chong)直徑 0.6～0.8mm 的(de)(de)孔(kong)(kong)(kong),與數(shu)(shu)控鉆(zhan)(zhan)床鉆(zhan)(zhan)孔(kong)(kong)(kong)相(xiang)比加工周期長(chang)且需要人(ren)工操(cao)作,由于最初工序加工的(de)(de)尺寸(cun)都很大(da),這樣沖(chong)孔(kong)(kong)(kong)的(de)(de)模具(ju)也相(xiang)應(ying)要大(da),因而模具(ju)價格(ge)就很貴(gui),雖然大(da)批量(liang)生(sheng)(sheng)產對降低成本有利(li)(li),但設備折舊(jiu)負擔大(da),小批量(liang)生(sheng)(sheng)產及靈活性無法與數(shu)(shu)控鉆(zhan)(zhan)孔(kong)(kong)(kong)相(xiang)競(jing)爭,所以至(zhi)今仍無法普(pu)及。

        但在最近數年里,沖(chong)(chong)孔(kong)(kong)(kong)技(ji)術的(de)(de)(de)(de)模具(ju)精密化和數控鉆孔(kong)(kong)(kong)兩方面都取(qu)得了很(hen)大的(de)(de)(de)(de)進步(bu),沖(chong)(chong)孔(kong)(kong)(kong)在柔性印制板(ban)(ban)上的(de)(de)(de)(de)實際應用(yong)已(yi)十分可(ke)行(xing)。最新的(de)(de)(de)(de)模具(ju)制造技(ji)術可(ke)制造能(neng)夠沖(chong)(chong)切基材厚(hou) 25um 的(de)(de)(de)(de)無膠黏劑型覆銅箔層壓板(ban)(ban)的(de)(de)(de)(de)直徑 75um 的(de)(de)(de)(de)孔(kong)(kong)(kong),沖(chong)(chong)孔(kong)(kong)(kong)的(de)(de)(de)(de)可(ke)靠性也(ye)(ye)相當高,如果(guo)沖(chong)(chong)切條(tiao)件合適甚至還可(ke)以(yi)沖(chong)(chong)直徑50um 的(de)(de)(de)(de)孔(kong)(kong)(kong)。沖(chong)(chong)孔(kong)(kong)(kong)裝置也(ye)(ye)已(yi)數控化,模具(ju)也(ye)(ye)能(neng)小型化,所以(yi)能(neng)很(hen)好地應用(yong)于(yu)柔性印制板(ban)(ban)沖(chong)(chong)孔(kong)(kong)(kong),數控鉆孔(kong)(kong)(kong)和沖(chong)(chong)孔(kong)(kong)(kong)都不能(neng)用(yong)于(yu)盲孔(kong)(kong)(kong)加工。

03

激光鉆孔

       用激(ji)光(guang)(guang)(guang)可以鉆(zhan)最微細(xi)的通孔(kong),用于(yu)柔性印制板鉆(zhan)通孔(kong)的激(ji)光(guang)(guang)(guang)鉆(zhan)孔(kong)機有受(shou)激(ji)準分子激(ji)光(guang)(guang)(guang)鉆(zhan)機、沖擊式二氧(yang)化碳激(ji)光(guang)(guang)(guang)鉆(zhan)機、YAG(釔(yi)鋁(lv)石榴石)激(ji)光(guang)(guang)(guang)鉆(zhan)機、氬(ya)氣激(ji)光(guang)(guang)(guang)鉆(zhan)機等。

       沖擊(ji)式(shi)二(er)氧化(hua)碳(tan)激(ji)(ji)光(guang)鉆(zhan)(zhan)(zhan)(zhan)(zhan)機僅能夠對基(ji)材的(de)絕(jue)緣(yuan)(yuan)層進(jin)行(xing)鉆(zhan)(zhan)(zhan)(zhan)(zhan)孔(kong)(kong)(kong)(kong)(kong)(kong)加工(gong)(gong),而 YAG 激(ji)(ji)光(guang)鉆(zhan)(zhan)(zhan)(zhan)(zhan)機可以對基(ji)材的(de)絕(jue)緣(yuan)(yuan)層和銅(tong)箔進(jin)行(xing)鉆(zhan)(zhan)(zhan)(zhan)(zhan)孔(kong)(kong)(kong)(kong)(kong)(kong)加工(gong)(gong),鉆(zhan)(zhan)(zhan)(zhan)(zhan)絕(jue)緣(yuan)(yuan)層的(de)速度(du)(du)要明顯(xian)比鉆(zhan)(zhan)(zhan)(zhan)(zhan)銅(tong)箔的(de)速度(du)(du)快,僅用同(tong)一(yi)種激(ji)(ji)光(guang)鉆(zhan)(zhan)(zhan)(zhan)(zhan)孔(kong)(kong)(kong)(kong)(kong)(kong)機進(jin)行(xing)所有(you)的(de)鉆(zhan)(zhan)(zhan)(zhan)(zhan)孔(kong)(kong)(kong)(kong)(kong)(kong)加工(gong)(gong)生產(chan)效(xiao)率不(bu)可能很(hen)高(gao)。一(yi)般是首先對銅(tong)箔進(jin)行(xing)蝕(shi)(shi)(shi)刻(ke),先形成孔(kong)(kong)(kong)(kong)(kong)(kong)的(de)圖形,然后去除(chu)絕(jue)緣(yuan)(yuan)層從而形成通孔(kong)(kong)(kong)(kong)(kong)(kong),這樣(yang)激(ji)(ji)光(guang)就能鉆(zhan)(zhan)(zhan)(zhan)(zhan)極其微小孔(kong)(kong)(kong)(kong)(kong)(kong)徑的(de)孔(kong)(kong)(kong)(kong)(kong)(kong)。但此時由于上下孔(kong)(kong)(kong)(kong)(kong)(kong)的(de)位(wei)置精(jing)(jing)度(du)(du)可能會制約鉆(zhan)(zhan)(zhan)(zhan)(zhan)孔(kong)(kong)(kong)(kong)(kong)(kong)的(de)孔(kong)(kong)(kong)(kong)(kong)(kong)徑。如果是鉆(zhan)(zhan)(zhan)(zhan)(zhan)盲孔(kong)(kong)(kong)(kong)(kong)(kong),只要把一(yi)面(mian)(mian)的(de)銅(tong)箔蝕(shi)(shi)(shi)刻(ke)掉(diao),不(bu)存在上下位(wei)置精(jing)(jing)度(du)(du)問題(ti)。該工(gong)(gong)藝與在下面(mian)(mian)所敘述的(de)等離子體蝕(shi)(shi)(shi)孔(kong)(kong)(kong)(kong)(kong)(kong)和化(hua)學蝕(shi)(shi)(shi)孔(kong)(kong)(kong)(kong)(kong)(kong)雷同(tong)。

       目(mu)前受激(ji)(ji)(ji)準(zhun)分子(zi)激(ji)(ji)(ji)光加(jia)工的(de)(de)孔(kong)(kong)是(shi)最(zui)微細(xi)的(de)(de)。受激(ji)(ji)(ji)準(zhun)分子(zi)激(ji)(ji)(ji)光是(shi)紫外(wai)線,直(zhi)(zhi)接破壞基(ji)底層樹脂(zhi)的(de)(de)結(jie)構,使樹脂(zhi)分子(zi)離散,產生的(de)(de)熱量(liang)極小(xiao),所(suo)以(yi)可以(yi)把(ba)熱對(dui)孔(kong)(kong)周圍的(de)(de)損傷(shang)程度限制在(zai)最(zui)小(xiao)范圍內,孔(kong)(kong)壁光滑垂直(zhi)(zhi)。如果能把(ba)激(ji)(ji)(ji)光束進一(yi)步縮小(xiao)的(de)(de)話就能夠加(jia)工直(zhi)(zhi)徑 10～20um 的(de)(de)孔(kong)(kong)。當然板厚孔(kong)(kong)徑比越(yue)大,濕式鍍(du)銅也(ye)就越(yue)難。受激(ji)(ji)(ji)準(zhun)分子(zi)激(ji)(ji)(ji)光技術鉆孔(kong)(kong)的(de)(de)問(wen)題是(shi)高(gao)分子(zi)的(de)(de)分解會(hui)產生炭黑附著于孔(kong)(kong)壁,所(suo)以(yi)必(bi)須采取(qu)某些手段(duan)在(zai)電鍍(du)之前對(dui)表面進行清(qing)洗(xi)以(yi)除去炭黑。但是(shi)激(ji)(ji)(ji)光加(jia)工盲孔(kong)(kong)時,激(ji)(ji)(ji)光的(de)(de)均(jun)勻(yun)性也(ye)存在(zai)一(yi)定(ding)的(de)(de)問(wen)題,會(hui)產生竹(zhu)子(zi)狀(zhuang)殘留物。

       受激(ji)(ji)準分(fen)子(zi)激(ji)(ji)光最大的難點(dian)就是鉆孔速度慢,加工成本太高。所以只限(xian)于用在(zai)高精度、高可靠(kao)性(xing)微(wei)小孔的加工。

       沖擊式二(er)(er)氧化碳(tan)(tan)激(ji)(ji)光一般是(shi)用二(er)(er)氧化碳(tan)(tan)氣體為激(ji)(ji)光源,輻射的(de)(de)(de)是(shi)紅(hong)外線,與受(shou)激(ji)(ji)準(zhun)(zhun)分子(zi)(zi)激(ji)(ji)光因熱效(xiao)應而(er)燃(ran)燒(shao)分解(jie)樹(shu)脂分子(zi)(zi)不同,它屬于熱分解(jie),加工的(de)(de)(de)孔(kong)形狀要比(bi)(bi)受(shou)激(ji)(ji)準(zhun)(zhun)子(zi)(zi)激(ji)(ji)光差得(de)多(duo),可(ke)以加工的(de)(de)(de)孔(kong)徑基(ji)本(ben)上是(shi) 70～100um,但加工速(su)(su)度(du)明(ming)顯的(de)(de)(de)比(bi)(bi)受(shou)激(ji)(ji)準(zhun)(zhun)分子(zi)(zi)激(ji)(ji)光速(su)(su)度(du)快得(de)多(duo),鉆孔(kong)的(de)(de)(de)成本(ben)也低得(de)多(duo)。即使如(ru)此,仍比(bi)(bi)下(xia)面所敘述的(de)(de)(de)等離子(zi)(zi)體蝕(shi)孔(kong)法(fa)和化學(xue)蝕(shi)孔(kong)法(fa)加工成本(ben)高得(de)多(duo),特(te)別單(dan)位面積孔(kong)數(shu)多(duo)時更是(shi)如(ru)此。

       沖擊式(shi)二氧化碳激(ji)(ji)光(guang)要(yao)注意的(de)(de)是加工(gong)(gong)(gong)盲孔時,激(ji)(ji)光(guang)只能發(fa)射至銅(tong)箔表(biao)面(mian),對表(biao)面(mian)的(de)(de)有機物(wu)完全不必去除,為了(le)穩定(ding)清洗銅(tong)表(biao)面(mian),應以化學蝕刻或等離子體蝕刻作為后處理。從(cong)技術的(de)(de)可能性(xing)來考慮(lv),激(ji)(ji)光(guang)鉆(zhan)孔工(gong)(gong)(gong)藝(yi)(yi)(yi)用于卷帶工(gong)(gong)(gong)藝(yi)(yi)(yi)基本上沒有什(shen)么困難,但考慮(lv)到(dao)工(gong)(gong)(gong)序的(de)(de)平(ping)衡及(ji)設備的(de)(de)投資所占的(de)(de)比例,它就不占優勢,但帶式(shi)芯(xin)片自(zi)動化焊接(jie)工(gong)(gong)(gong)藝(yi)(yi)(yi)(TAB,Tape Automated Bonding)寬度狹小,采用卷帶工(gong)(gong)(gong)藝(yi)(yi)(yi)可以提高鉆(zhan)孔速度,在這方面(mian)已經有了(le)實際的(de)(de)例子。

三

孔金屬化

       柔(rou)性(xing)印制板的孔(kong)金屬化與(yu)剛性(xing)印制板的孔(kong)金屬工藝基本相同。

       近年來(lai)出現了取代化學鍍,采用形成碳導(dao)電層技(ji)術的直接電鍍工(gong)藝(yi)。柔性印制板的孔(kong)金屬化也引入了這一技(ji)術。

       柔(rou)(rou)性(xing)印制板(ban)由于其柔(rou)(rou)軟(ruan),需要(yao)有特別的(de)固(gu)定夾具(ju),夾具(ju)不僅(jin)能把柔(rou)(rou)性(xing)印制板(ban)固(gu)定,而(er)且在(zai)(zai)鍍(du)(du)液中還必須穩定,否(fou)則鍍(du)(du)銅(tong)厚度(du)不均(jun)勻,這也是在(zai)(zai)蝕刻工序中引起斷線和橋接的(de)重要(yao)原因。要(yao)想獲得均(jun)勻的(de)鍍(du)(du)銅(tong)層,必須使柔(rou)(rou)性(xing)印制板(ban)在(zai)(zai)夾具(ju)內繃緊,而(er)且還要(yao)在(zai)(zai)電(dian)極的(de)位置和形(xing)狀上下功夫。

       孔金(jin)屬化(hua)外(wai)包(bao)加工(gong)(gong),要盡可能避免外(wai)包(bao)給(gei)無(wu)柔性(xing)印(yin)制板(ban)孔化(hua)經驗的工(gong)(gong)廠,如(ru)果沒有(you)柔性(xing)印(yin)制板(ban)專用(yong)的電鍍線,孔化(hua)質量(liang)是無(wu)法保證(zheng)的。

四

銅箔表面的清洗

       為了提高(gao)抗(kang)蝕(shi)掩膜的附著力,涂(tu)布(bu)抗(kang)蝕(shi)掩膜之前要對銅(tong)箔(bo)表面進行清洗,即使(shi)這樣(yang)的簡單工序對于柔性印制板(ban)也(ye)需要特(te)別注(zhu)意。

         一般清洗有化學清洗工藝和機械研磨工藝,對于制造精密圖形時,大多數場合是把兩種清流工藝結合起來進行表面處理。機械研磨使用拋刷的方法,拋刷材料過硬會對銅箔造成損傷,太軟又會研磨不充分。一般是用尼龍刷,必須對拋刷的長短和硬度進行仔細研究。使用兩根拋刷輥,放在傳送帶的上面,旋轉方向與皮帶傳送方向相反,但此時如果拋刷輥壓力過大,基材將受到很大的張力而被拉長,這是引起尺寸變化的重要原因之一。

       如果銅箔表面處理不干凈,那么與抗蝕掩膜的附著力就差,這樣就會降低蝕刻工序的合格率。近來由于銅箔板質量的提高,單面電路情況下也可以省略表面清洗工序。但 100μm 以下的精密圖形,表面清洗是必不可少的工序。
        抗蝕劑的涂布-雙面 FPC 制造工藝現在,抗蝕劑的涂布方法根據電路圖形的精密度和產量分為以下三種方法:絲網漏印法、干膜/感光法、液態抗蝕劑感光法。

       現在,抗蝕劑的涂布(bu)方法(fa)根(gen)據電路圖形的精密度和產量分為以下(xia)三種(zhong)方法(fa)：絲網漏印(yin)法(fa)、干膜/感(gan)光法(fa)、液態(tai)抗蝕劑感(gan)光法(fa)。

        抗蝕油墨采用(yong)絲網漏印法(fa)(fa)直接把線(xian)路(lu)(lu)圖(tu)(tu)形(xing)(xing)漏印在銅箔表面上,這(zhe)是(shi)最常用(yong)的技術,適用(yong)于大(da)批量生產(chan),成本低(di)廉。形(xing)(xing)成的線(xian)路(lu)(lu)圖(tu)(tu)形(xing)(xing)的精度可以(yi)達到線(xian)寬 / 間距  0.2～0.3 mm,但不適用(yong)于更精密(mi)的圖(tu)(tu)形(xing)(xing)。隨著微細化這(zhe)種方法(fa)(fa)逐步(bu)不能適應。與以(yi)下所敘述的干膜法(fa)(fa)相比需要有(you)一定技術的操(cao)作(zuo)人員,操(cao)作(zuo)人員必須經過(guo)多年的培(pei)養,這(zhe)是(shi)不利的因(yin)素。   

       干膜法只要設備、條件齊全就可制得 70～80μm 的線寬圖形。現在 0.3mm 以下的精密圖形大部分都可以用干膜法形成抗蝕線路圖形。采用干膜,其厚度是 15～25μm,條件允許,批量水平可以制作 30～40μm 線寬的圖形。

       當選擇干(gan)膜(mo)時(shi)(shi),必須(xu)根據與銅箔板、工藝的匹配性(xing)并通(tong)過試驗來(lai)確定(ding)。實驗的水平(ping)即使有(you)好的分辨能力,但并不一定(ding)在大批量生產使用時(shi)(shi)能有(you)很高的合格率(lv)。柔性(xing)印制板薄且(qie)易于彎曲(qu),如果(guo)選用硬一點的干(gan)膜(mo)則其較脆而隨動(dong)性(xing)差,所(suo)以也就會產生裂縫或(huo)剝落從而使蝕刻的合格率(lv)降(jiang)低。

       干膜(mo)(mo)(mo)(mo)(mo)是(shi)(shi)卷狀的(de)(de),生產設備和作業較簡單。干膜(mo)(mo)(mo)(mo)(mo)是(shi)(shi)由較薄的(de)(de)聚酯(zhi)保(bao)(bao)護(hu)膜(mo)(mo)(mo)(mo)(mo)、光致抗蝕(shi)膜(mo)(mo)(mo)(mo)(mo)和較厚的(de)(de)聚酯(zhi)離(li)型膜(mo)(mo)(mo)(mo)(mo)等三層結構所構成。在(zai)貼膜(mo)(mo)(mo)(mo)(mo)之前首先要把離(li)型膜(mo)(mo)(mo)(mo)(mo)(又(you)稱隔(ge)膜(mo)(mo)(mo)(mo)(mo))剝(bo)去,再用熱輥將其貼壓(ya)在(zai)銅(tong)箔的(de)(de)表面上(shang),顯影(ying)前再撕(si)去上(shang)面保(bao)(bao)護(hu)膜(mo)(mo)(mo)(mo)(mo)(又(you)稱載體(ti)膜(mo)(mo)(mo)(mo)(mo)或(huo)覆蓋膜(mo)(mo)(mo)(mo)(mo)),一般柔(rou)(rou)性(xing)印制板(ban)(ban)兩側(ce)有導向定位孔,干膜(mo)(mo)(mo)(mo)(mo)可稍(shao)微比要貼膜(mo)(mo)(mo)(mo)(mo)的(de)(de)柔(rou)(rou)性(xing)銅(tong)箔板(ban)(ban)狹窄(zhai)一點。剛性(xing)印制板(ban)(ban)用的(de)(de)自(zi)動(dong)貼膜(mo)(mo)(mo)(mo)(mo)裝置(zhi)不適用于(yu)柔(rou)(rou)性(xing)印制板(ban)(ban)的(de)(de)貼膜(mo)(mo)(mo)(mo)(mo),必須進行部分(fen)的(de)(de)設計(ji)更(geng)改。由于(yu)干膜(mo)(mo)(mo)(mo)(mo)貼膜(mo)(mo)(mo)(mo)(mo)與其他的(de)(de)工(gong)序相比線速度大,所以不少廠都不用自(zi)動(dong)化貼膜(mo)(mo)(mo)(mo)(mo),而是(shi)(shi)采用手工(gong)貼膜(mo)(mo)(mo)(mo)(mo)。

        貼好干膜之后,為了使其穩定,應放置 1 5～20min 之后再進行曝光。

       線(xian)路圖形(xing)線(xian)寬如果在 30μm 以下(xia),用(yong)干膜(mo)形(xing)成圖形(xing),合(he)格率會(hui)明顯下(xia)降。批量(liang)生產時(shi)一般都不使用(yong)干膜(mo),而使用(yong)液態光(guang)(guang)致(zhi)抗蝕(shi)(shi)劑。涂(tu)布條件不同,涂(tu)布的(de)厚度(du)會(hui)有所(suo)變化,如果涂(tu)布厚度(du) 5～15μm的(de)液態光(guang)(guang)致(zhi)抗蝕(shi)(shi)劑于 5μm 厚的(de)銅箔上,實驗室的(de)水平能夠蝕(shi)(shi)刻 10μm 以下(xia)的(de)線(xian)寬。

        液態(tai)光(guang)致抗(kang)蝕劑,涂布(bu)之后必(bi)須進行干燥和烘焙,由(you)于這一(yi)熱處(chu)理會(hui)對抗(kang)蝕膜(mo)性能產生(sheng)很大影(ying)響(xiang),所以必(bi)須嚴格控制(zhi)干燥條件。