Contact aligners

Sci. in press). In these studies, the PIQ (2.0 ym thick) was used as an underlayer. Thus, the film consisting of the polymer 11 and PIQ prepared on a silicon wafer was exposed to deep UV-light with the use of Canon contact aligner PLA-521 through a photomask for 5 to 6 s (UV intensity 72 mV/cm2 at 254 nm). The resulting film was then developed with a 1 5 mixture of toluene and isopropyl alcohol for 15 s and rinsed with isopropyl alcohol for 15 s. A positive resist pattern was obtained after treatment of the film pattern with 02 RIE under the condition of 0.64 W/cm2 (RF power 7 MHz, 02 pressure 3 mtorr). 

Deep-UV exposures were performed on a Karl Suss MA 56M contact aligner fitted with a Lambda Physik KrF excimer laser (X.=248.7 nm) operating at an output of 13 mJ/cm2/sec at 100 Hz. Resist films were dip developed in aqueous TMAH and rinsed in distilled water. 

Table 2.4 Polyimides (lA-19) used as alignment layers, especially as non-contact alignment layers, for LCDs.

Figure 2.19 Schematic representation of the anisotropic crosslinking of a photoreactive coumarin polymer by the action of polarised UV light to produce an anisotropic network as a non-contact alignment layer. E indicates the polarisation direction of the incident beam. ...

Figure 6.7 Plot of the relative intensity (A.U.) of polarised electroluminescence against wavelength (nm) of a bilayer OLED consisting of an electron-transport and emission layer represented by a nematic network formed by polymerising compound (86) with isotropic UV light and a combined hole-transport and a coumarin non-contact alignment layer doped with 4.4,4-tris(naphthylyl)-N-(phenylamino) triphenylamine.

Stepper Example. The resist evaluation method developed in this work for Cobilt contact aligners is a general method, and has also... 

The examples shown in this section are conservative and are based on use of a SVG EV-1 contact aligner. Although 2pm line and space are routinely achievable and better than 1pm overlay is achievable, o =5pm / =10pm and 7=10pm. 

Lateral shift can also be used to consolidate more mask layers. In contact aligners, this approach has some disadvantages. Because the pattern lacks rotational symmetry, the die size is limited to the mask movement distance in the alignment system used. 

The early 1960s saw the development of the contact aligners, the first practical exposure systems that were sold commercially by companies such as Microtech, Electroglas, Preco, and Kulicke Soffa. In these contact aligners, patterns were imaged and exposed in a photoresist via a mask that was in intimate physical contact with the upper surface of the photoresist. Such exposures created yield... 

The proximity printers achieved a resolution of roughly 4-6 p,m they had higher yield than the contact aligners. Their yield was limited because of the difficulties associated with controlhng the gap spacing between the mask and the resist-coated wafer. 

In this Chapter an overview of the state of the art of liquid crystal applications is given, in particular the current market development for LCD s and the recent developments using non contact alignment techniques like photoalignment and ion-beam alignment. 

Photolithography process using contact aligner, (a) Ultraviolet exposure of photoresist with photomask, (b) Pattern on photomask is transferred to photoresist after development. 

Lithographic evaluation of the resists was carried out in a KSM Karl Suss deep-UV contact aligner. We find that the sensitivity of the resists of PS with 2.4 wt-% of 1 is 5-10 mJ cm", while a sensitivity of 30-40 mJ cm is found for the resists of PS with 14.7 wt-% of 3. PS alone has a sensitivity of about 3000 mJ cm". The smallest feature in the mask (0.5 yxm) could be resolved (Figure 3). Swelling of the polymer was observed under these non-optimized conditions, suggesting that furAer improvement of the resolution of the resists may be possible. 

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