A . 背面研磨帶之整體構成圖1係本發明之一實施形態之背面研磨帶之概略剖面圖。背面研磨帶100具備：基材10；及黏著劑層20，其配置於基材10之至少單側。雖然未圖示，但本發明之背面研磨帶於供使用前之期間，為了保護黏著面，亦可於黏著劑層之外側設置剝離襯墊。 背面研磨帶之厚度較佳為50 μm～500 μm、更佳為150 μm～350 μm。只要為此種該範圍，則可得到能提高半導體晶圓之背面磨削精度之背面研磨帶。 背面研磨帶之於25℃下之黏著力較佳為0.1 N/20 mm～5 N/20 mm、更佳為0.2 N/20 mm～3 N/20 mm。再者，於本說明書中黏著力係指將鏡面晶圓(矽製)作為試驗板，根據依據JIS Z 0237(2000)之方法(貼合條件：2 kg輥往復1次、熟化：於測定溫度下1小時、剝離速度：300 mm/分鐘、剝離角度：90°)進行測定之黏著力。
B . 黏著劑層上述黏著劑層包含(甲基)丙烯酸系黏著劑。(甲基)丙烯酸系黏著劑可為熱硬化型黏著劑、活性能量線硬化型黏著劑等硬化型黏著劑，亦可為感壓型黏著劑。較佳使用硬化型之黏著劑。若使用硬化型之黏著劑，則能夠得到殘膠更少之背面研磨帶。 上述(甲基)丙烯酸系黏著劑包含(甲基)丙烯酸系聚合物作為基礎聚合物。再者，「基礎聚合物」係指黏著劑中所包含之聚合物之主要成分。又，該說明書中「主要成分」於沒有特別記載之情形時係指包含超過50重量%之成分。 上述(甲基)丙烯酸系聚合物包含具有碳數為8以上之側鏈之構成單位。作為此種(甲基)丙烯酸系聚合物，例如較佳為單體原料之聚合物，其包含具有碳數為8以上之支鏈狀或直鏈狀之烷基之(甲基)丙烯酸烷基酯作為主要單體，且包含與該主要單體具有共聚性之副單體。此處主要單體係指佔有上述單體原料中之單體組成之超過50重量%之成分。 於本發明中，藉由使用包含具有碳數為8以上之側鏈之構成單位之(甲基)丙烯酸系聚合物，而形成耐酸性及耐鹼性優異之黏著劑層。又，根據具備該黏著劑層之本發明之背面研磨帶，即使於將該背面研磨帶貼附至被黏物(半導體晶圓)而構成積層體，使該積層體浸漬於酸性液體或鹼性液體中之情形時，亦可防止酸性液體或鹼性液體浸入至被黏物與黏著劑層之間。進而，上述黏著劑層與耐酸性及耐鹼性優異之基材(例如，由聚烯烴或聚苯乙烯形成之基材)之密接性優異，因此若組合該基材與上述黏著劑層而構成背面研磨帶，則本發明之效果變得更加顯著。又，藉由使用(甲基)丙烯酸系聚合物，而可得到具有適於背面研磨步驟之黏著力，剝離性亦優異、可無殘膠地剝離之背面研磨帶。 作為具有碳數為8以上之支鏈狀或直鏈狀之烷基之(甲基)丙烯酸烷基酯，例如可列舉出丙烯酸2-乙基己酯(2EHA)、(甲基)丙烯酸辛酯、(甲基)丙烯酸異辛酯、(甲基)丙烯酸壬酯、(甲基)丙烯酸異壬酯、(甲基)丙烯酸癸酯、(甲基)丙烯酸異癸酯、(甲基)丙烯酸月桂酯(LA)、(甲基)丙烯酸硬脂酯等。 源自具有碳數為8以上之支鏈狀或直鏈狀之烷基之(甲基)丙烯酸烷基酯的構成單位之含有比例，相對於(甲基)丙烯酸系聚合物100重量份較佳為超過50重量份、更佳為60重量份～98重量份、更佳為70重量份～95重量份、進而佳為75重量份～85重量份。 作為上述副單體，例如可列舉出下述之單體。副單體可單獨使用1種或組合使用2種以上。 具有碳數為7以下之支鏈狀或直鏈狀之烷基之(甲基)丙烯酸烷基酯； 含羧基單體：例如丙烯酸(AA)、甲基丙烯酸(MAA)、丁烯酸等乙烯性不飽和單羧酸；馬來酸、衣康酸、檸康酸等乙烯性不飽和二羧酸及其酐(馬來酸酐、衣康酸酐等)； 含羥基單體：例如(甲基)丙烯酸2-羥乙酯、(甲基)丙烯酸2-羥丙酯、(甲基)丙烯酸3-羥丙酯、(甲基)丙烯酸2-羥丁酯等(甲基)丙烯酸羥基烷基酯類；乙烯醇、烯丙醇等不飽和醇類；2-羥乙基乙烯基醚、4-羥丁基乙烯基醚、二乙二醇單乙烯基醚等醚系化合物； 含胺基單體：例如(甲基)丙烯酸胺基乙酯、(甲基)丙烯酸N,N-二甲基胺基乙酯、(甲基)丙烯酸第三丁基胺基乙酯； 含環氧基單體：例如(甲基)丙烯酸縮水甘油酯、(甲基)丙烯酸甲基縮水甘油酯、烯丙基縮水甘油醚； 含氰基單體：例如丙烯腈、甲基丙烯腈； 含酮基單體：例如雙丙酮(甲基)丙烯醯胺、雙丙酮(甲基)丙烯酸酯、甲基乙烯酮、乙基乙烯酮、乙醯乙酸烯丙酯、乙醯乙酸乙烯酯； 具有含氮原子之環之單體：例如N-乙烯基-2-吡咯烷酮、N-甲基乙烯基吡咯烷酮、N-乙烯基吡啶、N-乙烯基哌啶酮、N-乙烯基嘧啶、N-乙烯基哌嗪、N-乙烯基吡嗪、N-乙烯基吡咯、N-乙烯基咪唑、N-乙烯基噁唑、N-乙烯基嗎啉、N-乙烯基己內醯胺、N-(甲基)丙烯醯基嗎啉； 含烷氧基甲矽烷基單體：例如3-(甲基)丙烯醯氧基丙基三甲氧基矽烷、3-(甲基)丙烯醯氧基丙基三乙氧基矽烷、3-(甲基)丙烯醯氧基丙基甲基二甲氧基矽烷、3-(甲基)丙烯醯氧基丙基甲基二乙氧基矽烷； 含異氰酸酯基單體：(甲基)丙烯醯基異氰酸酯、2-(甲基)丙烯醯氧乙基異氰酸酯、間異丙烯基-α,α-二甲基苄基異氰酸酯。 源自上述副單體之構成單位之含有比例，相對於(甲基)丙烯酸系聚合物100重量份而低於50重量份、更佳為2重量份～40重量份、進而佳為5重量份～30重量份。若為此種範圍，則可形成凝集力高、且密接性優異之黏著劑層。 上述(甲基)丙烯酸系聚合物之重量平均分子量較佳為20萬～300萬、更佳為25萬～150萬。重量平均分子量可藉由GPC(gel permeation chromatography，凝膠滲透層析法)(溶劑：THF(tetrahydrofuran，四氫呋喃))測定而得。 上述黏著劑亦可進而包含任意適合之添加劑。作為上述添加劑，例如可列舉出聚合起始劑、交聯劑、可塑劑、黏著性賦予劑、老化防止劑、填充劑、著色劑、帶電防止劑、界面活性劑等。上述添加劑可單獨使用，亦可組合使用2種以上。於使用2種以上之添加劑時，可1種1種地添加，亦可同時添加2種以上之添加劑。上述添加劑之調配量可設定為任意適合之量。 作為上述黏著性賦予劑，可使用任意適合之黏著性賦予劑。作為黏著性賦予劑，例如可使用黏著賦予樹脂。作為黏著賦予樹脂之具體例，可列舉出松香系黏著賦予樹脂(例如，未改性松香、改性松香、松香酚系樹脂、松香酯系樹脂等)、萜烯系黏著賦予樹脂(例如，萜烯系樹脂、萜烯酚系樹脂、苯乙烯改性萜烯系樹脂、芳香族改性萜烯系樹脂、氫化萜烯系樹脂)、烴系黏著賦予樹脂(例如，脂肪族系烴樹脂、脂肪族系環狀烴樹脂、芳香族系烴樹脂(例如，苯乙烯系樹脂、二甲苯系樹脂等)、脂肪族/芳香族系石油樹脂、脂肪族/脂環族系石油樹脂、氫化烴樹脂、香豆酮系樹脂、香豆酮-茚系樹脂等)、酚系黏著賦予樹脂(例如，烷基苯酚系樹脂、二甲苯甲醛系樹脂、甲階酚醛樹脂、酚醛清漆樹脂等)、酮系黏著賦予樹脂、聚醯胺系黏著賦予樹脂、環氧系黏著賦予樹脂、彈性體系黏著賦予樹脂等。其中較佳為酚系黏著賦予樹脂、更佳為烷基苯酚系黏著賦予樹脂。使用由烷基苯酚系樹脂構成之黏著性賦予劑時，可使黏著劑強黏著力化，並且容易控制凝膠量。黏著性賦予劑可單獨使用、或組合使用2種以上。可藉由黏著性賦予劑之種類及調配量而調整黏著劑層之凝膠分率。換言之，對於黏著性賦予劑之種類及調配量，較佳根據基礎聚合物之種類，以黏著劑層之凝膠分率成為下述範圍(40%～80%)之方式適當地設定。 作為上述交聯劑，可使用任意適合之交聯劑。例如可列舉出異氰酸酯系交聯劑、環氧系交聯劑、三聚氰胺系交聯劑、過氧化物系交聯劑、尿素系交聯劑、金屬醇鹽系交聯劑、金屬螯合物系交聯劑、金屬鹽系交聯劑、碳化二亞胺系交聯劑、噁唑啉系交聯劑、氮丙啶系交聯劑、胺系交聯劑等。交聯劑可僅使用1種，亦可組合使用2種以上。再者，交聯劑之用量可根據使用用途設定為任意適合之值。於一實施形態中，交聯劑之用量相對於(甲基)丙烯酸系聚合物100重量份，較佳為10重量份以下、更佳為0.1重量份以上且低於1重量份、進而佳為0.1重量份以上且低於0.5重量份。於其他實施形態中，交聯劑之用量相對於基礎聚合物100重量份，較佳為10重量份以下、更佳為0.1重量份～3重量份、進而佳為0.2重量份以上且低於1.5重量份。再者，交聯劑較佳為根據基礎聚合物之種類、以黏著劑層之凝膠分率成為下述範圍(40%～80%)之方式使用適合之量。 上述黏著劑層之凝膠分率較佳為40%～80%、更佳為42%～78%、進而佳為60%～76%。只要為此種範圍，即使於將背面研磨帶貼附至被黏物(半導體晶圓)而構成積層體，使該積層體浸漬於酸性液體或鹼性液體之情形時，亦可防止酸性液體或鹼性液體浸入至被黏物與黏著劑層之間。又，可得到具有適於背面研磨步驟之黏著力，剝離性亦優異、可無殘膠地剝離之背面研磨帶。凝膠分率以下述方式測定。將約0.1g之黏著劑層包裹於具有0.2 μm直徑之孔之鐵氟龍(註冊商標)片(商品名「NTF1122」、日東電工股份公司製造)中，然後用風箏線捆綁，測定此時之重量，將該重量作為浸漬前重量。再者，浸漬前重量係黏著劑層、鐵氟龍片與風箏線之總重量。又，亦預先測定所使用之鐵氟龍片與風箏線之重量，將前述重量作為包袋重量。其次，將用鐵氟龍片包裹前述黏著劑層並用風箏線進行捆綁而得到之物品放入至裝滿醋酸乙酯之50 ml容器中，於室溫下靜置1週。然後，自容器中取出鐵氟龍片，於130℃下於乾燥機中進行2小時乾燥而除去醋酸乙酯，然後測定樣品重量，將該重量作為浸漬後重量。又，基於下述公式計算出凝膠分率。再者，下式中之A為浸漬後重量、B為包袋重量、C為浸漬前重量。 凝膠分率(重量%)=(A-B)/(C-B)×100 上述黏著劑層於23℃下之儲存模數G'較佳為0.05×10
6Pa～1.0×10
8Pa、更佳為0.1×10
6Pa～1.0×10
7Pa。具備具有此種儲存模數之黏著劑層之背面研磨帶，可有助於達成背面研磨步驟中之優異之磨削精度，且殘膠少。再者，關於儲存模數G'，可使用黏彈性測定裝置，於以下之測定條件下對寬度10 mm×長度50 mm×厚度2 mm之評價樣品(黏著劑層)進行測定。 ・模式：扭轉模式 ・板直徑：7.9 mm
・應變：1%(25℃) ・頻率：1 Hz ・測定範圍：-20℃～100℃ 上述黏著劑層之厚度較佳為10 μm～200 μm、更佳為15 μm～150 μm。
C . 基材作為構成上述基材之材料，可選擇任意適合之材料。作為構成基材之材料，例如可列舉出樹脂系材料(例如，片狀、網狀、織布、無紡布、發泡片)、紙、金屬等。基材可為單層，亦可為由相同材料或不同材料構成之多層。作為構成基材層之樹脂之具體例，例如可列舉出聚酯、聚烯烴、乙烯-醋酸乙烯酯共聚物、乙烯-(甲基)丙烯酸共聚物、乙烯-(甲基)丙烯酸酯共聚物、乙烯-丁烯共聚物、乙烯-己烯共聚物、聚氨酯、聚醚酮、聚乙烯醇、聚偏二氯乙烯、聚氯乙烯、氯乙烯-醋酸乙烯酯共聚物、聚醋酸乙烯酯、聚醯胺、聚醯亞胺、纖維素系樹脂、氟系樹脂、有機矽樹脂、聚醚、聚苯乙烯系樹脂(聚苯乙烯等)、聚碳酸酯、聚醚碸及其等之交聯物等。 於一實施形態中，作為上述基材，可使用由聚烯烴系樹脂或聚苯乙烯系樹脂構成之基材。使用此種基材時，可得到耐酸性及耐鹼性優異之背面研磨帶。作為聚烯烴系樹脂之具體例，可列舉出聚丙烯、聚乙烯、聚丁烯、其等之共聚物等。作為基材，亦可使用由上述樹脂構成之拉伸薄膜。 上述基材可為多層結構。於一實施形態中，可使用包含由聚烯烴系樹脂構成之層、及由其他樹脂構成之層之基材。作為與聚烯烴系樹脂組合之其他樹脂，例如可列舉出乙烯-醋酸乙烯酯共聚物、乙烯-(甲基)丙烯酸酯共聚物(EE(M)A、EM(M)A、EB(M)A)等。其中較佳為乙烯-醋酸乙烯酯共聚物。若採用由上述共聚物構成之層作為多層結構中之1層，則可形成柔軟性優異之基材。該基材可發揮緩衝背面研磨時之衝擊之功能(防破裂缺損功能)。 上述基材可利用任意適合之方法來製造。例如可藉由壓延製膜、流延製膜、吹脹擠出、T模擠出等方法製造。又，根據需要亦可進行拉伸處理而製造。 根據目的，亦可對上述基材實施任意適合之表面處理。作為該表面處理，可列舉出鉻酸處理、臭氧暴露、火焰暴露、高壓電擊暴露、電離輻射線處理、消光處理、電暈放電處理、底塗處理、交聯處理等。 上述基材之厚度較佳為10 μm～300 μm、更佳為30 μm～200 μm。 上述基材之於23℃下之拉伸彈性模數(楊氏模數)較佳為1×10
6Pa～1×10
11Pa、更佳為1×10
7Pa～1×10
10Pa。再者，拉伸彈性模數可依據JIS K 7161：2008進行測定(夾具間隔：50 mm、拉伸速度：300 mm/分鐘)。
D . 背面研磨帶之製造方法本發明之背面研磨帶可藉由將上述黏著劑塗覆於上述基材上而製造。作為黏著劑之塗覆方法，可採用棒塗機塗覆、氣刀塗覆、凹版塗覆、凹版逆轉塗覆、逆轉輥塗覆、模唇塗覆、模塗覆、浸漬塗覆、膠印、柔性印刷、絲網印刷等各種方法。又，亦可採用另行於剝離襯墊上形成黏著劑層後將其貼合於基材上之方法等。 於使用硬化型之黏著劑作為黏著劑時，亦可對黏著劑層實施硬化處理而調整該黏著劑層之特性(黏著力、彈性模數等)。作為硬化處理，例如可列舉出紫外線照射、加熱處理等。 [實施例] 以下藉由實施例對本發明進行具體說明，但本發明不限定於該些實施例。又，於實施例中只要沒有特別說明，「份」及「%」為重量基準。 [製造例1](甲基)丙烯酸系聚合物(I) 將丙烯酸2-乙基己酯(2EHA)64.2重量份、丙烯醯基嗎啉(ACMO)16.5重量份、丙烯酸羥乙酯(HEA)11.4重量份、與2-甲基丙烯醯氧乙基異氰酸酯(MOI)7.9重量份聚合，得到重量平均分子量(Mw)為約90萬之(甲基)丙烯酸系聚合物(I)(包含具有碳數為8之側鏈之構成單位之(甲基)丙烯酸系聚合物)。 [製造例2](甲基)丙烯酸系聚合物(II) 將甲基丙烯酸月桂酯(LMA)83.4重量份、甲基丙烯酸2-羥乙酯(HEMA)8.5重量份、及2-甲基丙烯醯氧乙基異氰酸酯(MOI)8.1重量份聚合，得到重量平均分子量(Mw)為約100萬之(甲基)丙烯酸系聚合物(II)(包含具有碳數為12之側鏈之構成單位之(甲基)丙烯酸系聚合物)。 [製造例3](甲基)丙烯酸系聚合物(III) 將丙烯酸2-乙基己酯(2EHA)100重量份、及丙烯酸羥乙酯(HEA)4重量份聚合，得到重量平均分子量(Mw)為約55萬之(甲基)丙烯酸系聚合物(III)(包含具有碳數為8之側鏈之構成單位之(甲基)丙烯酸系聚合物)。 [製造例4](甲基)丙烯酸系聚合物(IV) 將丙烯酸丁酯(BA)41.6重量份、丙烯酸羥乙酯(HEA)36.2重量份、及2-甲基丙烯醯氧乙基異氰酸酯(MOI)22.2重量份聚合，得到重量平均分子量(Mw)為約50萬之(甲基)丙烯酸系聚合物(IV)(包含具有碳數為4之側鏈之構成單位之(甲基)丙烯酸系聚合物)。 [實施例1] (黏著劑A之製備) 將製造例1中得到之(甲基)丙烯酸系聚合物(I)100重量份、黏著性賦予劑(烷基苯酚系黏著賦予樹脂；Arakawa Chemical Industries， Ltd.製造、商品名「Tamanol 526」)3重量份、交聯劑(異氰酸酯系交聯劑；東曹公司製造、商品名「CORONATE HX」)0.1重量份、及光聚合起始劑(BASF公司製造、商品名「IRGACURE 184」)3重量份混合，製備出黏著劑A。 (基材之製作) 藉由使用T模之共擠出，得到由包含聚丙烯(Japan Polypropylene Corporation製造、商品名「WSX02」)之層(厚度30 μm)、及包含乙烯-醋酸乙烯酯共聚物(Mitsui Du Pont Co.， Ltd.製造、商品名「P1007」)之層(厚度85 μm)構成之基材A。 (背面研磨帶之製作) 將上述黏著劑A塗佈於隔離件(三菱化學公司製造、商品名「MRF38」)上，於120℃加熱2分鐘而形成黏著劑層(厚度：20 μm)，將該黏著劑層轉印至基材A之乙烯-醋酸乙烯酯共聚物薄膜側，而得到包含基材及黏著劑層之背面研磨帶。 [實施例2] 將交聯劑之調配量設為0.2重量份，除此以外與實施例1相同地得到背面研磨帶。 [實施例3] 將交聯劑之調配量設為0.3重量份，除此以外與實施例1相同地得到背面研磨帶。 [實施例4] 不調配黏著性賦予劑，除此以外與實施例1相同地得到背面研磨帶。 [實施例5] (黏著劑B之製備) 將製造例2中得到之(甲基)丙烯酸系聚合物(II)100重量份、黏著性賦予劑(烷基苯酚系黏著賦予樹脂；Arakawa Chemical Industries， Ltd.製造、商品名「Tamanol 526」)3重量份、交聯劑(異氰酸酯系交聯劑；東曹公司製造、商品名「CORONATE HL」)1重量份、及光聚合起始劑(BASF公司製造、商品名「IRGACURE 184」)3重量份混合，製備出黏著劑B。 (背面研磨帶之製作) 使用黏著劑B代替黏著劑A，除此以外與實施例1相同地得到背面研磨帶。 [實施例6] 不調配黏著性賦予劑、且將交聯劑之調配量設為0.2重量份，除此以外與實施例5相同地得到背面研磨帶。 [實施例7] 使用包含延伸聚苯乙烯(kurabo industries Ltd.製造、商品名「Oidys #25」；厚度：25 μm)之基材代替基材A，除此以外與實施例5相同地得到背面研磨帶。 [實施例8] 使用包含聚萘二甲酸乙二醇酯(Teijin Limited製造、商品名「Teonex Q51#25」；厚度：25 μm)之基材代替基材A，除此以外與實施例5相同地得到背面研磨帶。 [實施例9] 使用包含聚醯亞胺(Du Pont-Toray Co.， Ltd.製造、商品名「Kapton100V#25」；厚度：25 μm)之基材代替基材A，除此以外與實施例5相同地得到背面研磨帶。 [實施例10] (黏著劑C之製備) 將製造例3中得到之(甲基)丙烯酸系聚合物(III)100重量份、黏著性賦予劑(烷基苯酚系黏著賦予樹脂；Arakawa Chemical Industries， Ltd.製造、商品名「Tamanol 526」)3重量份、及交聯劑(異氰酸酯系交聯劑；東曹公司製造、商品名「CORONATE L」)0.2重量份混合，製備出黏著劑C。 (背面研磨帶之製作) 使用黏著劑C代替黏著劑A，除此以外與實施例1相同地得到背面研磨帶。 [比較例1] 將交聯劑之調配量設為1重量份，除此以外與實施例1相同地得到背面研磨帶。 [比較例2] 不調配黏著性賦予劑，除此以外與比較例1相同地得到背面研磨帶。 [比較例3] 將交聯劑之調配量設為0.5重量份，除此以外與實施例1相同地得到背面研磨帶。 [比較例4] 將交聯劑之調配量設為1.5重量份，除此以外與實施例5相同地得到背面研磨帶。 [比較例5] 不調配黏著性賦予劑，除此以外與實施例5相同地得到背面研磨帶。 [比較例6] (黏著劑D之製備) 將製造例4中得到之(甲基)丙烯酸系聚合物(IV)100重量份、交聯劑(異氰酸酯系交聯劑；東曹公司製造、商品名「CORONATE L」)0.1重量份、及光聚合起始劑(BASF公司製造、商品名「IRGACURE 651」)3重量份進行混合，製備出黏著劑D。 (背面研磨帶之製作) 將上述黏著劑D塗佈於隔離件(三菱化學社製造、商品名「MRF38」)上，於120℃加熱2分鐘而形成黏著劑層(厚度：20 μm)，將該黏著劑層轉印於PET上，得到包含基材及黏著劑層之背面研磨帶。 [評價] 將於實施例及比較例中得到之背面研磨帶供於下述(1)～(4)之評價。結果示於表1。 (1)黏著劑層之凝膠分率 將約0.1g之黏著劑層包裹於具有0.2 μm直徑之孔之鐵氟龍(註冊商標)片(商品名「NTF1122」、日東電工股份公司製造)中，然後用風箏線捆綁，測定此時之重量，將該重量作為浸漬前重量。再者，浸漬前重量係黏著劑層、鐵氟龍片及風箏線之總重量。又，亦預先測定所使用之鐵氟龍片及風箏線之重量，將前述重量作為包袋重量。其次，將用鐵氟龍片包裹前述黏著劑層並用風箏線進行捆綁而得到之物品放入至裝滿醋酸乙酯之50 ml容器中，於室溫下靜置1週。然後，自容器中取出鐵氟龍片，於130℃於乾燥機中進行2小時乾燥而除去醋酸乙酯，然後測定樣品重量，將該重量作為浸漬後重量。基於下述式計算出凝膠分率。再者，下式中之A為浸漬後重量、B為包袋重量、C為浸漬前重量。 凝膠分率(重量%)=(A-B)/(C-B)×100 (2)耐蝕刻性(背面研磨帶之耐酸性及耐鹼性) 將96重量%H
2SO
4水溶液、及70重量%HNO
3水溶液進行混合(重量比：H
2SO
4/HNO
3=50/7)而製備混合酸。將背面研磨帶浸漬於該混合酸(常溫下)中2分鐘。 其次，將自混合酸中取出之上述背面研磨帶浸漬於45重量%KOH水溶液(60℃)中1分鐘。 然後，對背面研磨帶進行水洗，藉由目視確認基材之劣化、及液體向黏著劑層之浸入之有無。表1中，將未確認到基材之劣化之情況(包括實用中可容許程度之劣化)設為〇，將確認到基材之劣化之情況(劣化至不適宜實用之程度之情況)設為×。又，將未確認到液體向黏著劑層之浸入之情況設為〇，將確認到液體向黏著劑層之浸入之情況設為×。 (4)殘膠 將背面研磨帶黏貼於矽晶圓上，一面利用手工剝離用晶圓保持裝置(Nitto Seiki Co.， Ltd.製造 HMT-300)對晶圓進行真空吸附，一面於常溫(23℃)對背面研磨帶進行手工剝離。然後，藉由目視及100倍光學顯微鏡對背面研磨帶剝離後之晶圓表層實施觀察，進行殘膠有無之確認。表1中，將完全未確認到殘膠之情況設為〇，將確認到殘膠之情況設為×。 [表1]
自表1可知，本發明之背面研磨帶形成有耐酸性或耐鹼性優異之黏著劑層。又，藉由使用特定之樹脂作為構成基材之材料，可得到基材及黏著劑層均優異之背面研磨帶。
A. Overall Configuration of Back Grinding Tape FIG . 1 is a schematic sectional view of a back grinding tape according to an embodiment of the present invention. The back grinding tape 100 includes: a base material 10 ; and an adhesive layer 20 disposed on at least one side of the base material 10 . Although not shown, in order to protect the adhesive surface before the back grinding tape of the present invention is used, a release liner may be provided on the outside of the adhesive layer. The thickness of the back grinding tape is preferably from 50 μm to 500 μm, more preferably from 150 μm to 350 μm. If it is such a range, the back grinding tape which can improve the back grinding precision of a semiconductor wafer can be obtained. The adhesive force of the back grinding tape at 25°C is preferably 0.1 N/20 mm to 5 N/20 mm, more preferably 0.2 N/20 mm to 3 N/20 mm. Furthermore, in this specification, the adhesive force refers to a mirror wafer (made of silicon) as a test board, according to the method based on JIS Z 0237 (2000) (bonding condition: 2 kg roller reciprocates once, aging: at the measurement temperature 1 hour, peeling speed: 300 mm/min, peeling angle: 90°) to measure the adhesive force. B. Adhesive Layer The above-mentioned adhesive layer contains a (meth)acrylic adhesive. The (meth)acrylic adhesive may be a curable adhesive such as a thermosetting adhesive or an active energy ray curable adhesive, or may be a pressure sensitive adhesive. It is better to use hardening type adhesive. If a hardening adhesive is used, a back grinding tape with less residual glue can be obtained. The above-mentioned (meth)acrylic adhesive contains a (meth)acrylic polymer as a base polymer. In addition, "base polymer" refers to the main component of the polymer contained in the adhesive. In addition, the "main component" in this specification means a component containing more than 50% by weight unless otherwise specified. The said (meth)acryl-type polymer contains the structural unit which has a side chain which has 8 or more carbon atoms. Such a (meth)acrylic polymer is preferably, for example, a monomer raw material polymer containing a (meth)acrylic alkyl group having a branched or linear alkyl group having 8 or more carbon atoms. An ester is a main monomer, and contains a submonomer which is copolymerizable with this main monomer. Here, the main monomer system refers to a component occupying more than 50% by weight of the monomer composition in the above-mentioned monomer raw material. In the present invention, an adhesive layer excellent in acid resistance and alkali resistance is formed by using a (meth)acrylic polymer having a constituent unit having a side chain having 8 or more carbon atoms. Also, according to the back grinding tape of the present invention having the adhesive layer, even if the back grinding tape is attached to an adherend (semiconductor wafer) to form a laminate, the laminate is immersed in an acidic liquid or alkaline In the case of liquid, it can also prevent acidic liquid or alkaline liquid from immersing between the adherend and the adhesive layer. Furthermore, the above-mentioned adhesive layer has excellent adhesion to a base material having excellent acid resistance and alkali resistance (for example, a base material formed of polyolefin or polystyrene), so if the base material and the above-mentioned adhesive layer are combined to form If the back grinding tape is used, the effect of the present invention becomes more remarkable. In addition, by using a (meth)acrylic polymer, it is possible to obtain a back grinding tape which has an adhesive force suitable for the back grinding step, has excellent releasability, and can be peeled without adhesive residue. Examples of alkyl (meth)acrylates having a branched or straight-chain alkyl group having 8 or more carbon atoms include 2-ethylhexyl acrylate (2EHA), octyl (meth)acrylate , Isooctyl (meth)acrylate, Nonyl (meth)acrylate, Isononyl (meth)acrylate, Decyl (meth)acrylate, Isodecyl (meth)acrylate, Lauryl (meth)acrylate ester (LA), stearyl (meth)acrylate, etc. The content ratio of the constituent unit derived from the alkyl (meth)acrylate having a branched or linear alkyl group having 8 or more carbon atoms is preferably 100 parts by weight of the (meth)acrylic polymer It is more than 50 parts by weight, more preferably 60 to 98 parts by weight, more preferably 70 to 95 parts by weight, still more preferably 75 to 85 parts by weight. As said submonomer, the following monomers are mentioned, for example. A submonomer may be used individually by 1 type or in combination of 2 or more types. Alkyl (meth)acrylate having a branched or linear alkyl group with a carbon number of 7 or less; carboxyl group-containing monomers: such as vinyl acrylic acid (AA), methacrylic acid (MAA), crotonic acid, etc. unsaturated monocarboxylic acids; maleic acid, itaconic acid, citraconic acid and other ethylenically unsaturated dicarboxylic acids and their anhydrides (maleic anhydride, itaconic anhydride, etc.); hydroxyl-containing monomers: such as (methyl) Hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, etc. ; Vinyl alcohol, allyl alcohol and other unsaturated alcohols; 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and other ether compounds; Amino-containing monomers: For example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, tertiary butylaminoethyl (meth)acrylate; Epoxy-containing monomers: for example Glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, allyl glycidyl ether; cyano-containing monomers: such as acrylonitrile, methacrylonitrile; ketone-containing monomers: such as bis Acetone(meth)acrylamide, diacetone(meth)acrylate, methyl ketene, ethyl ketene, allyl acetylacetate, acetylvinyl acetate; monomers having rings containing nitrogen atoms : For example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinyl Pyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine; Alkoxysilyl-containing monomers: such as 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(methyl) base) acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane; isocyanate-containing monomer: (meth)acrylisocyanate , 2-(meth)acryloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate. The content ratio of the constituent units derived from the above-mentioned submonomers is less than 50 parts by weight, more preferably 2 to 40 parts by weight, and more preferably 5 parts by weight, based on 100 parts by weight of the (meth)acrylic polymer. ~30 parts by weight. Within such a range, an adhesive layer having a high cohesive force and excellent adhesion can be formed. The weight average molecular weight of the above-mentioned (meth)acrylic polymer is preferably from 200,000 to 3 million, more preferably from 250,000 to 1.5 million. The weight average molecular weight can be determined by GPC (gel permeation chromatography, gel permeation chromatography) (solvent: THF (tetrahydrofuran, tetrahydrofuran)). The above-mentioned adhesive may further include any suitable additives. As said additive, a polymerization initiator, a crosslinking agent, a plasticizer, a tackiness imparting agent, an anti-aging agent, a filler, a coloring agent, an antistatic agent, a surfactant etc. are mentioned, for example. These additives may be used alone or in combination of two or more. When two or more additives are used, they may be added one by one, or two or more additives may be added simultaneously. The compounding quantity of the said additive can be set to any suitable quantity. Any appropriate tackiness imparting agent can be used as the tackiness imparting agent. As the tackiness imparting agent, tackiness imparting resin can be used, for example. Specific examples of tackifying resins include rosin-based tackifying resins (for example, unmodified rosin, modified rosin, rosin phenolic resins, rosin ester resins, etc.), terpene-based tackifying resins (such as terpene olefin-based resin, terpene-phenolic resin, styrene-modified terpene-based resin, aromatic-modified terpene-based resin, hydrogenated terpene-based resin), hydrocarbon-based tackifying resin (for example, aliphatic hydrocarbon resin, fatty Family-based cyclic hydrocarbon resins, aromatic-based hydrocarbon resins (such as styrene-based resins, xylene-based resins, etc.), aliphatic/aromatic petroleum resins, aliphatic/alicyclic petroleum resins, hydrogenated hydrocarbon resins, Coumarone-based resins, coumarone-indene-based resins, etc.), phenolic adhesive-imparting resins (such as alkylphenol-based resins, xylene formaldehyde-based resins, resol resins, novolac resins, etc.), ketone-based adhesives Imparting resins, polyamide-based tackifying resins, epoxy-based tackifying resins, elastic-based tackifying resins, etc. Among these, phenol-based tackifying resins are preferable, and alkylphenol-based tackifying resins are more preferable. When using an adhesiveness imparting agent composed of an alkylphenol-based resin, the adhesive force of the adhesive can be strengthened, and the amount of gel can be easily controlled. The tackiness imparting agent can be used individually or in combination of 2 or more types. The gel fraction of the adhesive layer can be adjusted by the type and amount of the adhesive imparting agent. In other words, it is preferable to appropriately set the type and amount of the adhesive agent so that the gel fraction of the adhesive layer falls within the following range (40% to 80%) according to the type of base polymer. Any appropriate crosslinking agent can be used as the above-mentioned crosslinking agent. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, and metal chelate-based crosslinking agents. Cross-linking agent, metal salt-based cross-linking agent, carbodiimide-based cross-linking agent, oxazoline-based cross-linking agent, aziridine-based cross-linking agent, amine-based cross-linking agent, etc. The crosslinking agent may be used alone or in combination of two or more. Furthermore, the amount of the crosslinking agent can be set to any appropriate value according to the purpose of use. In one embodiment, the amount of the crosslinking agent is preferably 10 parts by weight or less, more preferably 0.1 parts by weight or more and less than 1 part by weight relative to 100 parts by weight of the (meth)acrylic polymer, and more preferably 0.1 weight part or more and less than 0.5 weight part. In other embodiments, the amount of the crosslinking agent is preferably 10 parts by weight or less, more preferably 0.1 parts by weight to 3 parts by weight, and more preferably 0.2 parts by weight or more and less than 1.5 parts by weight relative to 100 parts by weight of the base polymer. parts by weight. Furthermore, it is preferable to use an appropriate amount so that the gel fraction of an adhesive layer may become the following range (40%-80%) according to the kind of base polymer. The gel fraction of the adhesive layer is preferably from 40% to 80%, more preferably from 42% to 78%, and still more preferably from 60% to 76%. As long as it is within this range, even when the back grinding tape is attached to an adherend (semiconductor wafer) to form a laminate, and the laminate is immersed in an acidic liquid or an alkaline liquid, it is possible to prevent acidic liquid or The alkaline liquid is immersed between the adherend and the adhesive layer. In addition, a back grinding tape having an adhesive force suitable for a back grinding step and having excellent releasability and being able to be peeled without adhesive residue can be obtained. The gel fraction is measured in the following manner. About 0.1 g of the adhesive layer was wrapped in a Teflon (registered trademark) sheet (trade name "NTF1122", manufactured by Nitto Denko Co., Ltd.) with a hole in diameter of 0.2 μm, and then tied with a kite string to measure the Weight, this weight is taken as the weight before dipping. Furthermore, the weight before dipping refers to the total weight of the adhesive layer, the Teflon sheet and the kite string. Also, the weight of the Teflon sheet and the kite string used is also measured in advance, and the aforementioned weight is used as the weight of the bag. Next, the article obtained by wrapping the adhesive layer with a Teflon sheet and binding it with a kite string was put into a 50 ml container filled with ethyl acetate, and left to stand at room temperature for 1 week. Then, the Teflon sheet was taken out from the container, dried in a drier at 130° C. for 2 hours to remove ethyl acetate, and the weight of the sample was measured, which was taken as the weight after immersion. Moreover, the gel fraction was calculated based on the following formula. Furthermore, A in the following formula is the weight after dipping, B is the weight of the bag, and C is the weight before dipping. Gel fraction (weight %)=(AB)/(CB)×100 The storage modulus G' of the above-mentioned adhesive layer at 23°C is preferably 0.05×10 6 Pa～1.0×10 8 Pa, more preferably 0.1×10 6 Pa to 1.0×10 7 Pa. The back grinding tape with the adhesive layer having such a storage modulus can help to achieve excellent grinding accuracy in the back grinding step with less adhesive residue. In addition, storage modulus G' can be measured on the evaluation sample (adhesive layer) of 10 mm in width x 50 mm in length x 2 mm in thickness using a viscoelasticity measuring device under the following measurement conditions.・Mode: Twist Mode ・Board Diameter: 7.9 mm ・Strain: 1% (25°C) ・Frequency: 1 Hz ・Measurement range: -20°C to 100°C The thickness of the adhesive layer is preferably 10 μm to 200 μm, more preferably 15 μm to 150 μm. C. Substrate Any suitable material can be selected as the material constituting the above substrate . As a material which comprises a base material, resin-type material (for example, sheet shape, mesh shape, woven fabric, nonwoven fabric, foam sheet), paper, metal, etc. are mentioned, for example. The substrate can be a single layer or multiple layers made of the same material or different materials. Specific examples of the resin constituting the substrate layer include polyester, polyolefin, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, Ethylene-butene copolymer, ethylene-hexene copolymer, polyurethane, polyether ketone, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide Amines, polyimides, cellulose-based resins, fluorine-based resins, silicone resins, polyethers, polystyrene-based resins (polystyrene, etc.), polycarbonate, polyether-based resins, and their cross-linked products, etc. . In one embodiment, as the base material, a base material made of polyolefin resin or polystyrene resin can be used. When such a substrate is used, a back grinding tape excellent in acid resistance and alkali resistance can be obtained. Specific examples of polyolefin-based resins include polypropylene, polyethylene, polybutene, and copolymers thereof. As the substrate, stretched films made of the above-mentioned resins can also be used. The aforementioned substrate may have a multilayer structure. In one embodiment, a base material including a layer made of a polyolefin resin and a layer made of another resin can be used. Examples of other resins to be combined with polyolefin resins include ethylene-vinyl acetate copolymers, ethylene-(meth)acrylate copolymers (EE(M)A, EM(M)A, EB(M) A) etc. Among them, ethylene-vinyl acetate copolymer is preferable. When a layer composed of the above-mentioned copolymer is used as one layer in the multilayer structure, a substrate having excellent flexibility can be formed. The substrate can play the function of cushioning the impact of back grinding (the function of preventing crack and defect). The aforementioned substrates can be produced by any suitable method. For example, it can be produced by methods such as calendering film forming, casting film forming, inflation extrusion, and T-die extrusion. Moreover, stretching processing can also be performed and manufactured as needed. According to the purpose, any suitable surface treatment can also be performed on the above-mentioned substrate. Examples of the surface treatment include chromic acid treatment, ozone exposure, flame exposure, high-voltage electric shock exposure, ionizing radiation treatment, matting treatment, corona discharge treatment, primer treatment, and crosslinking treatment. The thickness of the above substrate is preferably 10 μm to 300 μm, more preferably 30 μm to 200 μm. The tensile elastic modulus (Young's modulus) of the substrate at 23°C is preferably 1×10 6 Pa to 1×10 11 Pa, more preferably 1×10 7 Pa to 1×10 10 Pa. In addition, the tensile modulus can be measured based on JIS K 7161:2008 (clamp interval: 50 mm, tensile speed: 300 mm/min). D. Method of Manufacturing Back Grinding Tape The back grinding tape of the present invention can be manufactured by coating the above-mentioned adhesive on the above-mentioned substrate. As the method of coating the adhesive, bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, die lip coating, die coating, dip coating, offset printing, Various methods such as flexographic printing and screen printing. In addition, a method in which an adhesive layer is separately formed on a release liner and bonded to a substrate may be employed. When a hardening adhesive is used as the adhesive, the adhesive layer can also be hardened to adjust the properties of the adhesive layer (adhesive force, elastic modulus, etc.). As curing treatment, ultraviolet irradiation, heat treatment, etc. are mentioned, for example. [Examples] The present invention will be specifically described below using examples, but the present invention is not limited to these examples. In addition, unless otherwise specified in the Examples, "parts" and "%" are based on weight. [Manufacturing Example 1] (Meth) Acrylic Polymer (I) 64.2 parts by weight of 2-ethylhexyl acrylate (2EHA), 16.5 parts by weight of acrylmorpholine (ACMO), hydroxyethyl acrylate (HEA) 11.4 parts by weight, polymerized with 7.9 parts by weight of 2-methacryloxyethyl isocyanate (MOI), to obtain a weight average molecular weight (Mw) of about 900,000 (meth)acrylic polymer (I) (including A (meth)acrylic polymer having a constituent unit of 8 side chains). [Production Example 2] (Meth)acrylic polymer (II) 83.4 parts by weight of lauryl methacrylate (LMA), 8.5 parts by weight of 2-hydroxyethyl methacrylate (HEMA), and 2-methacrylic acid 8.1 parts by weight of acyloxyethyl isocyanate (MOI) were polymerized to obtain a (meth)acrylic polymer (II) (including constituent units having a side chain with 12 carbon atoms) with a weight average molecular weight (Mw) of about 1 million. (meth)acrylic polymers). [Manufacturing Example 3] (Meth)acrylic polymer (III) 100 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of hydroxyethyl acrylate (HEA) were polymerized to obtain a weight average molecular weight (Mw ) is about 550,000 (meth)acrylic polymer (III) (a (meth)acrylic polymer including a constituent unit having a side chain having 8 carbon atoms). [Manufacturing Example 4] (Meth) Acrylic Polymer (IV) 41.6 parts by weight of butyl acrylate (BA), 36.2 parts by weight of hydroxyethyl acrylate (HEA), and 2-methacryloxyethyl isocyanate ( MOI) 22.2 parts by weight polymerization, to obtain a weight average molecular weight (Mw) of about 500,000 (meth)acrylic polymer (IV) (comprising (meth)acrylic polymers having a constituent unit of a side chain with 4 carbons polymer). [Example 1] (Preparation of Adhesive A) 100 parts by weight of the (meth)acrylic polymer (I) obtained in Production Example 1, an adhesive agent (alkylphenol-based adhesive resin; Arakawa Chemical Industries , Ltd., trade name "Tamanol 526") 3 parts by weight, a cross-linking agent (isocyanate-based cross-linking agent; manufactured by Tosoh Corporation, trade name "CORONATE HX") 0.1 parts by weight, and a photopolymerization initiator (BASF Adhesive A was prepared by mixing 3 parts by weight of "IRGACURE 184" manufactured by the company. (Preparation of base material) By co-extrusion using a T-die, a layer (thickness 30 μm) consisting of polypropylene (manufactured by Japan Polypropylene Corporation, trade name "WSX02") and an ethylene-vinyl acetate copolymer was obtained. Substrate A composed of a layer (thickness: 85 μm) of (Mitsui Du Pont Co., Ltd., trade name “P1007”). (Preparation of Back Grinding Tape) The above-mentioned adhesive A was coated on a separator (manufactured by Mitsubishi Chemical Corporation, trade name "MRF38"), and heated at 120° C. for 2 minutes to form an adhesive layer (thickness: 20 μm). The adhesive layer was transferred to the ethylene-vinyl acetate copolymer film side of the substrate A to obtain a back grinding tape comprising the substrate and the adhesive layer. EXAMPLE 2 Except having made the compounding quantity of a crosslinking agent into 0.2 weight part, it carried out similarly to Example 1, and obtained the back grinding tape. EXAMPLE 3 Except having made the compounding quantity of a crosslinking agent into 0.3 weight part, it carried out similarly to Example 1, and obtained the back grinding tape. [Example 4] A back grinding tape was obtained in the same manner as in Example 1 except that the tackifier was not prepared. [Example 5] (Preparation of Adhesive B) 100 parts by weight of the (meth)acrylic polymer (II) obtained in Production Example 2, an adhesive agent (alkylphenol-based adhesive resin; Arakawa Chemical Industries , Ltd., trade name "Tamanol 526") 3 parts by weight, a crosslinking agent (isocyanate-based crosslinking agent; Tosoh Corporation, trade name "CORONATE HL") 1 part by weight, and a photopolymerization initiator (BASF Adhesive B was prepared by mixing 3 parts by weight of "IRGACURE 184" manufactured by the company. (Preparation of back grinding tape) Except having used adhesive agent B instead of adhesive agent A, it carried out similarly to Example 1, and obtained the back grinding tape. [Example 6] A back grinding tape was obtained in the same manner as in Example 5 except that the adhesiveness imparting agent was not prepared and the compounding amount of the crosslinking agent was 0.2 parts by weight. [Example 7] Instead of the substrate A, the rear surface was obtained in the same manner as in Example 5, except that a substrate containing expanded polystyrene (manufactured by kurabo industries Ltd., trade name "Oidys #25"; thickness: 25 μm) was used instead of the substrate A. Grinding belt. [Example 8] In place of the base material A, a base material containing polyethylene naphthalate (manufactured by Teijin Limited, trade name "Teonex Q51#25"; thickness: 25 μm) was used instead of the base material A, except that it was the same as Example 5 to obtain a backgrinding tape. [Example 9] Instead of the base material A, a base material containing polyimide (manufactured by Du Pont-Toray Co., Ltd., trade name "Kapton100V#25"; thickness: 25 μm) was used, and it was the same as in Example 9 except that 5. A back grinding tape was obtained in the same manner. [Example 10] (Preparation of Adhesive C) 100 parts by weight of the (meth)acrylic polymer (III) obtained in Production Example 3, an adhesive agent (alkylphenol-based adhesive resin; Arakawa Chemical Industries , Ltd., trade name "Tamanol 526") 3 parts by weight, and a crosslinking agent (isocyanate-based crosslinking agent; Tosoh Corporation, trade name "CORONATE L") 0.2 parts by weight were mixed to prepare an adhesive C. (Preparation of back grinding tape) Except having used adhesive agent C instead of adhesive agent A, it carried out similarly to Example 1, and obtained the back grinding tape. COMPARATIVE EXAMPLE 1 Except having made the compounding quantity of a crosslinking agent into 1 weight part, it carried out similarly to Example 1, and obtained the back grinding tape. [Comparative Example 2] A backside grinding tape was obtained in the same manner as in Comparative Example 1 except that the tackifier was not prepared. COMPARATIVE EXAMPLE 3 Except having made the compounding quantity of a crosslinking agent into 0.5 weight part, it carried out similarly to Example 1, and obtained the back grinding tape. COMPARATIVE EXAMPLE 4 Except having made the compounding quantity of a crosslinking agent into 1.5 weight part, it carried out similarly to Example 5, and obtained the back grinding tape. COMPARATIVE EXAMPLE 5 Except not having prepared the tackiness imparting agent, it carried out similarly to Example 5, and obtained the back grinding tape. [Comparative Example 6] (Preparation of Adhesive D) 100 parts by weight of the (meth)acrylic polymer (IV) obtained in Production Example 4, a crosslinking agent (isocyanate crosslinking agent; manufactured by Tosoh Corporation, commercial product Adhesive D was prepared by mixing 0.1 parts by weight of "CORONATE L") and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "IRGACURE 651"). (Preparation of Back Grinding Tape) The above-mentioned adhesive D was coated on a separator (manufactured by Mitsubishi Chemical Corporation, trade name "MRF38"), and heated at 120° C. for 2 minutes to form an adhesive layer (thickness: 20 μm). The adhesive layer is transferred on the PET to obtain a back grinding tape comprising the base material and the adhesive layer. [Evaluation] The back grinding tapes obtained in Examples and Comparative Examples were subjected to the following evaluations (1) to (4). The results are shown in Table 1. (1) Gel fraction of the adhesive layer Wrap about 0.1 g of the adhesive layer in a Teflon (registered trademark) sheet (trade name "NTF1122", manufactured by Nitto Denko Co., Ltd.) having holes with a diameter of 0.2 μm , and then bundled with a kite string, measure the weight at this time, and use this weight as the weight before dipping. Furthermore, the weight before dipping refers to the total weight of the adhesive layer, the Teflon sheet and the kite string. Also, the weight of the Teflon sheet and the kite string used is also measured in advance, and the aforementioned weight is used as the weight of the bag. Next, the article obtained by wrapping the adhesive layer with a Teflon sheet and binding it with a kite string was put into a 50 ml container filled with ethyl acetate, and left to stand at room temperature for 1 week. Then, the Teflon sheet was taken out from the container, dried in a drier at 130° C. for 2 hours to remove ethyl acetate, and the weight of the sample was measured, which was taken as the weight after immersion. The gel fraction was calculated based on the following formula. Furthermore, A in the following formula is the weight after dipping, B is the weight of the bag, and C is the weight before dipping. Gel fraction (weight%)=(AB)/(CB)×100 (2) Etching resistance (acid and alkali resistance of back grinding tape) 96% by weight H 2 SO 4 aqueous solution, and 70% by weight The HNO 3 aqueous solution was mixed (weight ratio: H 2 SO 4 /HNO 3 =50/7) to prepare a mixed acid. The back grinding tape was immersed in this mixed acid (at normal temperature) for 2 minutes. Next, the above-mentioned back grinding tape taken out from the mixed acid was immersed in a 45% by weight KOH aqueous solution (60° C.) for 1 minute. Then, the back grinding tape was washed with water, and the deterioration of the base material and the presence or absence of penetration of the liquid into the adhesive layer were confirmed visually. In Table 1, the case where the deterioration of the base material was not confirmed (including deterioration to a practically tolerable level) was set as 0, and the case where the deterioration of the base material was confirmed (the case where the deterioration was unsuitable for practical use) was set as × . Moreover, the case where the infiltration of the liquid into the adhesive layer was not confirmed was made into 0, and the case where the infiltration of the liquid into the adhesive layer was confirmed was made into x. (4) Residual glue Stick the back grinding tape on the silicon wafer, and vacuum absorb the wafer with a wafer holding device for manual peeling (HMT-300 manufactured by Nitto Seiki Co., Ltd.), and place it at room temperature (23 °C) Manual peeling of the back grinding tape. Then, the surface layer of the wafer after peeling off the back grinding tape was observed visually and with a 100X optical microscope to confirm the presence or absence of adhesive residue. In Table 1, the case where no adhesive residue was confirmed was set at 0, and the case where adhesive residue was confirmed was set as x. [Table 1] As can be seen from Table 1, the back grinding tape of the present invention has an adhesive layer excellent in acid resistance or alkali resistance. Moreover, by using a specific resin as a material which comprises a base material, the back grinding tape excellent in both a base material and an adhesive agent layer can be obtained.
