Comparing the contrast curves of the supplier-recommended MIBK/IPA (1:3) to MIBK, it was found that using undiluted MIBK yields a 54% higher sensitivity at the cost of a similar (53%) contrast loss. The other four developers exhibit a
sensitivity and contrast performance between those of MIBK/IPA (1:3) and MIBK. In particular, two developers, n-amyl acetate and IPA/water (7:3), provide a relatively high sensitivity and contrast as compared to the other developers. The surfaces of the LY333531 manufacturer developed patterns were also inspected by optical microscopy, and it was found that all of the developers provide a uniform thickness loss with increasing dose except for xylene/methanol (3:1). Using Selleckchem QNZ xylene/methanol (3:1),
the dissolution is non-uniform with certain exposed areas dissolving more rapidly than others, leaving a porous resist surface. Perhaps a technique Selleckchem Selonsertib such as ultrasonic agitation may be useful in this regard. An additional document [see Additional file 1] compares (a) SML contrast curves at 10 and 30 keV and (b) the clearance dose at 10, 20, and 30 keV, for selected developers. Figure 2 SML contrast curves generated using 30 keV on 300- to 330-nm-thick resist. The development was performed for 20 s in MIBK (squares), n-amyl acetate (triangles), IPA/water (7:3) (crosses), xylene (stars), xylene/methanol (3:1) (circles), and MIBK/IPA (1:3) (diamonds). In FigureĀ 3, comparing the contrast curves of SML and PMMA, both developed in MIBK/IPA (1:3) for 20 s, it was found that SML is 71%
less sensitive than PMMA and has a 7% higher contrast. However, when SML is developed in IPA/water (7:3), a 41% sensitivity improvement is realized as compared to SML in MIBK/IPA (1:3), enabling the sensitivity of SML to be Tryptophan synthase comparable to that of PMMA in MIBK/IPA (1:3). This behavior is similar to PMMA – the sensitivity of PMMA developed in IPA/water (7:3) improves by 30% as compared to PMMA developed in MIBK/IPA (1:3) [21]. The sensitivity improvement of SML is achieved with a minor trade-off in contrast – SML in IPA/water (7:3) has a 13% lower contrast than SML in MIBK/IPA (1:3). The IPA/water (7:3) mixture provides the highest contrast versus sensitivity trade-off. By arranging SML developers with increasing clearance dose as shown in FigureĀ 4, it was found that IPA/water (7:3) has a higher-than-average contrast and the best contrast-weighted sensitivity. The quantity contrast-weighted sensitivity has been introduced as our figure of merit to factor in sensitivity while selecting the developer with the best contrast. The IPA/water developer has other merits including cost, safety, and experience of the EBL community using it as a developer for PMMA [1, 19, 21] and ZEP [19, 22] at both ambient and cold development conditions.