Lithographic testing

In their search for higher-resolution resists and potential replacements for KTFR, lithographers tested many photosensitive coatings, one of which was the positive-tone printing plate material from the Kalle Company of Wiesbaden, invented by Oskar Siiss, and based on the DNQ-novolac resist system described above. This material turned out to be the first DNQ-novolac resist used in semiconductor lithography. 

Experimental agents were evaluated on dot reproducibility of the lithographic printing plate after development. Testing results are provided in Table 1 where the symbol A indicates good dot reproducibility and where reproducibility deteriorates in order of the symbols , C, D, and E. 

The surface characteristics of reworked substrates and several rework processes are described later in several tables and the discussion. The substrate condition following the rework process is characterized by the results of three tests ESCA or XPS [19] surface chemical composition spectra, actual lithographic resist pattern lift testing [2, 6], and water droplet contact angle measurement, 0HjO [3]. 

Lithographic and printing lakes should also be resistant to spirit varnishes, when the latter are used as a protection or to render the colours less brilliant. To test lakes from this point of view, it suffices to subject a sharply outlined print to the action of a few drops of spirit varnish, which covers partly the design and partly the white ground. After a few minutes the excess of the varnish is poured off and the print examined when dry to see if the ground has remained perfectly white and if the outlines of the design are still sharp. 

Microstructuring of the surface of a polymer membrane on solid support is commonly performed by various lithographic techniques. In previous applications is was not necessary or it was not tested whether the microstructured pores extend down to the neat support surface or whether the lower part of the pore remains filled with bulk polymer of with residues of the lithographic process. It could be shown by FTIR spectroscopic imaging for the first time, that residues remain inside the pores, which chemical origin the residues have and how the microstructuring process can be optimized towards completely empty pores, even if the diameter of the pores does not exceed a couple of micrometers. 

The imaging properties of PVTMSK were studied by spin coating 350-nm-thick films on silicon wafers or on silicon wafers precoated with a 1.5-(xm-thick layer of hard-baked photoresist, exposing them to mid- or deep-UV radiation through a chromium-on-quartz lithographic mask, and developing the pattern as described earlier. This scheme was used to test the intended application of PVTMSK as an imaging material for two-layer resist applications. The densest patterns resolved were composed of l-(xm coded lines and spaces. 

An overview of the lithographic process is presented with particular emphasis on the role that surface and colloid chemistry plays. Recent research has shown the importance of these chemistries in fountain solution, ink and plate interactions and the effect of these interactions on the dynamic behavior of the lithographic ink on press. Data on the rheological behavior of preformed fountain solution/ink emulsions is presented along with an evaluation of prints made with the inks on an actual press run. The importance of pre-testing the emulsification behavior of printing inks in predicting their printability is demonstrated. 

Although many types of compounds have been tested as sensitizers in phenolic host resins (Novolacs, Resols, etc.) (S), all commercial positive resists employ aromatic diazoquinones of some type which photochemically generate base soluble products via Wolff rearrangement initiated by the loss of nitrogen (6). A staggering variety of diazoketones have been synthesized and evaluated for lithographic purposes, but derivatives of J[ and 2 are most commonly employed (5). 

The ultimate test of usefulness is, of course, the lithographic performance of a resist. The often-quoted sensitivity of PMMA of 50 pC/cm2 assumes conventional developing conditions and is measured by competitive dissolution rates of exposed and unexposed films. A secondary measure of sensitivity for positive-working resists is the G(s) value, the yield of chain scissions per 100 e.v. of absorbed energy. In this case, mea-... 

A very simple method to test the lithographic resolution of a material is to use TEM grids (TEM = transmission electron microscopy) as a contact-shadow masks [57]. AFM investigations of crosslinked layers, structured by using the method described above, show, that the used grids have been nicely reproduced. 

The second focus of this chapter is the full-color capability. The combination with the crosslinking strategy led to a novel class of semiconductive materials smart (negative) photoresists. In addition to the fabrication of multilayer structures the layers could be simply patterned laterally by the use of a photolithographic process. In the few cases where the lithographic resolution was tested, it was easily sufficient for RGB pixilated deposition. In addition, these materials come with additional new features ( added values ). 

This resist was used for early ArF lithographic exposure tool testing purposes. 

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