Positive PMMA e-Beam Resist AR-P 630– 670 series

PMMA resist 50K – 950K for the production of semiconductor and masks

2-layer Coating and lift=off application

Processing instructions for coating

Large undercut structures (lift-off) are obtained if PMMA resists with different molecular weight are chosen for a two-component system. As upper layer, an ethyl lactate PMMA is recommended since ethyl lactate does not, in contrast to other solvents, attack the second layer. For the lower layer, a chlorobenzene, anisole or ethyl lactate PMMA is suitable. Both tempering steps are performed at 150 °C.


large undercut (low resolution): bottom layer 50K, upper layer 200K, 600K or 950K.

High resolution (smaller undercut): bottom layer 600K, upper layer 950K.

懸浮剝離法所需的下切型阻劑結構可以不同分子量的PMMA阻劑作為2層結構的組合. 上層的PMMA建議選用以乳酸乙酯(ethyl lactate)為溶劑,因相較於其它溶劑,乳酸乙酯不會攻擊第底層阻劑. 底層PMMA的溶劑可以是氯苯(chlorobenzene),苯甲醚(anisole),或乳酸乙酯(ethyl lactate). 兩層阻劑可同時於150℃軟烤.


下切結構較大(低解析度): 分子量, 底層PMMA 50k, 上層PMMA 200k.

下切結構較小(高解析度): 分子量, 底層PMMA 600k, 上層PMMA 950k.

Investigations of 2-layer PMMA lift-off structures

For these tests, the 2-layer systems were coated as shown to the left and tempered at 180 °C, 60 s, followed by irradiation with different doses (30 kV) and development (AR 600-60, IPA).

雙層組合結構的測試,例如左圖的組合,塗佈後以180℃軟烤,再以30kV加速電壓在不圖劑量下曝光後顯影(AR 600-60, IPA)

The system 50K/200K is more sensitive, the double layer is completely developed at 1500 pC/cm2. The variant 600K/950K in contrast requires the higher dose of 2200 pC/cm2. With increasing dose, also a larger undercut is generated if the 50K/200K system is used, which is thus predestined for complicated lift-off procedures. Variant 600K/950K may be utilized for higher total film thicknesses (> 500 nm) and is a reliable lift-off system for simple applications. For these investigations, always AR 600-60 (IPA) was used as developer which explains both the comparably high doses and the good process stability.

分子量 50k/200k的組合,其敏感度較高,雙層完全顯開約需1500 pC/cm的曝光能量. 分子量 600k/950k則需2200pC/cm的較高劑量. 複雜的懸浮剝離製程,一般先以50k/200k的組合, 增加曝光劑量可獲得較大的下切結構. 600k/950k的組合,則應用於膜厚需求較高的製程(>500nm).

這些研究皆以AR 600-60(IPA)為顯影劑,因此需要較高的曝光劑量,但製程相當穩定.

The left diagram shows a comparison of the sensitivity of AR-P 679.03 in two different developers. Under otherwise identical conditions (30 kV, 165 nm film thickness), the sensitivity is almost twice as high if the standard developer AR 600-55 is used as compared to AR 600-60 (IPA). A development with IPA however results in a considerably higher contrast (10.5 : 6.6). This developer is thus predestined for higher resolutions. Experience furthermore shows that the process window is significantly larger as compared to faster developers.Dose deviations of e.g., 10 % are tolerated without any quality loss.

下圖以AR-P 679.03為例顯示在2種不同顯影劑下的敏感度的比較. 在相同參數條件下(30kV, 165nm film thickness), 使用顯影劑AR 600-55比AR 600-50 (IPA),敏感度高出2.

然而使用IPA顯影有高對比的特性(10.5:6.6). 因此IPA用於較高解析度的製程. 實驗也顯示其製程穩定度高於快速顯影的製程.