Wang Juan, Dong Zhikai, Chen Jingwen, Chen Shuangjun
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China.
Suqian Advanced Materials Institute, Nanjing Tech University, Suqian 223800, China.
Materials (Basel). 2023 Aug 29;16(17):5911. doi: 10.3390/ma16175911.
UV debonding acrylate adhesive (UDAA) plays a crucial role in the semiconductor industry, where its excellent adhesion is required to ensure the stability of silicon wafers and leave no residue on the surface after UV irradiation. The necessary UV debonding is achieved through the formation of rigid networks by the reactions of all the vinyl groups in the system. Acrylate copolymers with vinyl groups are typically obtained by the grafting reaction of isocyanate with a side-chain hydroxyl comonomer. However, these grafting reactions easily fail due to early cross-link formation. In this study, we illustrate a straightforward method for preparing UDAA by conducting a postgrafting reaction after one-step mixing of isocyanate functional monomer (IPDI-H) and hydroxyl acrylate copolymers (BA-H), thereby skipping the abovementioned vinyl grafting process. The chemical structures of the synthesized IPDI-H and BA-H were confirmed using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (H-NMR) analysis. Gel permeation chromatography (GPC) was employed to determine their molecular weights, while differential scanning calorimetry (DSC) was used to determine their glass transition temperatures. The postgrafting reactions successfully introduced vinyl groups onto the polyacrylate copolymer chains, resulting in high bonding strength during use and a significant decrease in peeling strength after UV irradiation. Rheological methods, including the three-interval thixotropy test (3ITT) and tack test modes, were employed to characterize a series of acrylate UV debonding adhesives. The recovery percentage of the storage modulus in the 3ITT mode indicated that a 0.6 wt% isocyanate curing agent made the UV debonding adhesives resistant to deformation. From the maximum normal force in the tack test mode, it was found that UDAA with 10 wt% PETA monomer and 30 wt% C5 tackifying resin exhibited excellent combined adhesion and debonding properties, which were further confirmed by peel strength tests. Microscope images of the wafer surfaces after removing the adhesive tapes demonstrated the excellent UV debonding properties achieved after 40 s of UV irradiation through the postgrafting reaction. The prepared UDAA has excellent properties; the peel strength can reach 15 N/25 mm before UV irradiation and can be reduced to 0.5 N/25 mm after ultraviolet irradiation. This research establishes a comprehensive method for understanding and applying UDAA in various applications.
紫外光解聚丙烯酸酯胶粘剂(UDAA)在半导体行业中起着至关重要的作用,在该行业中,需要其具有出色的粘附力以确保硅片的稳定性,并且在紫外光照射后表面不留任何残留物。通过体系中所有乙烯基的反应形成刚性网络来实现必要的紫外光解聚。含乙烯基的丙烯酸酯共聚物通常通过异氰酸酯与侧链羟基共聚单体的接枝反应获得。然而,这些接枝反应由于早期交联的形成而容易失败。在本研究中,我们阐述了一种制备UDAA的直接方法,即在将异氰酸酯官能单体(IPDI-H)和羟基丙烯酸酯共聚物(BA-H)一步混合后进行后接枝反应,从而跳过上述乙烯基接枝过程。使用傅里叶变换红外光谱(FTIR)和质子核磁共振(H-NMR)分析确认了合成的IPDI-H和BA-H的化学结构。采用凝胶渗透色谱(GPC)测定它们的分子量,同时使用差示扫描量热法(DSC)测定它们的玻璃化转变温度。后接枝反应成功地将乙烯基引入聚丙烯酸酯共聚物链上,在使用过程中产生高粘结强度,并且在紫外光照射后剥离强度显著降低。采用流变学方法,包括三区间触变性测试(3ITT)和粘性测试模式,对一系列丙烯酸酯紫外光解聚胶粘剂进行表征。3ITT模式下储能模量的恢复百分比表明,0.6 wt%的异氰酸酯固化剂使紫外光解聚胶粘剂具有抗变形能力。从粘性测试模式下的最大法向力发现,含有10 wt% PETA单体和30 wt% C5增粘树脂的UDAA表现出优异的综合粘附和解聚性能,这通过剥离强度测试得到进一步证实。去除胶带后晶圆表面的显微镜图像显示,通过后接枝反应在紫外光照射40秒后实现了优异的紫外光解聚性能。制备的UDAA具有优异的性能;紫外光照射前剥离强度可达15 N/25 mm,紫外光照射后可降至0.5 N/25 mm。本研究建立了一种全面的方法来理解和应用UDAA于各种应用中。