Photomask

About: Photomask is a research topic. Over the lifetime, 7917 publications have been published within this topic receiving 54524 citations. The topic is also known as: photoreticle & reticle.

Resolution enhancement through optical proximity correction and stepper parameter optimization for 0.12-μm mask pattern

Abstract: As the design rule of semiconductor microchips gets smaller, the distortion of a patterned image due to the optical proximity effect (OPE) becomes the limiting factor in the mass production. We developed an optical proximity correction (OPC) program that can be applied to a strong or attenuated phase shift mask as well as to a binary mask. The OPC program named OPERA is based on a stochastic approach as other rule-free OPC programs, but it has tow remarkable points. Firstly, proper cost function and optimization strategy enable us to achieve very closely clustered mask pattern that could be manufactured at a reasonable cost. Secondly, OPERA can carry out the optimization of illumination parameters for any modified illumination methods, such as, annular or quadrupole using the critical dimensions information of mask patterns.

Photomask inspection method and inspection tape therefor

Abstract: A method of inspecting a photomask for use in photolithography which accounts for the rounding of corners of features that occurs during manufacture of the photomask. A data tape used in the preparation of the photomask is first provided. An inspection tape is then prepared by modifying the data on the data tape to account for rounding of the features during preparation of the photomask. Finally, an inspection device is used to compare features on the photomask to data on the inspection tape corresponding to such features.

Optically selective microlens photomask using self-assembled smectic liquid crystal defects array

Abstract: 2010 WILEY-VCH Verlag Gmb Microlens photolithographic fabrication using self-assembled materials has attracted considerable attention in recent years because the techniques involved are very simple, inexpensive, and provide a route to the fabrication of large-area patterns. Several materials, which include colloids, hydrogels, and liquid crystals (LCs), have been used to fabricate self-assembled microlens arrays for photolithographic use. Colloidal microspheres, 3mm in diameter, were embedded in a transparent polymer membrane. These spheres acted as lenses to reduce centimeter-scale images to micrometer-scale images in the image plane, providing a simple way to produce spontaneous assembly over a large area, with the appropriate feature size, using microlens arrays optimized for visible light. Biomimetic hydrogels were also used to fabricate microlens arrays for photolithography. These systems adopted a conventional microlens system morphology, containing spherical or hemispherical geometric shapes with a homogeneous refractive index. A more advanced microlens system has used LCs for the fabrication of active devices, because the molecular orientations within a LC can be easily controlled by an external electric field. A radial distribution of the refractive index can be attained through application of an axially distributed electric field. However, previous LC-based microlens systems required complex thick LC cell structures to control the molecular orientations of the nematic LC. Such cell structures included circular hole-patterned electrodes and polymer stabilizers. In this Communication, we report a new type of microstructure for the fabrication of optically selectivemicrolens arrays. This system uses a periodic toric focal conic domain (TFCD) of smectic LCs as a photomask, combining two imaging elements, microlens arrays and clear windows. The shape and focusing mechanism of the TFCD microlens photomasks are very different from those of conventional microlens photomasks, which use spherical (or hemispherical) structures with homogeneous refractive indices. TFCD microlens photomasks have several remarkable features. First, the periodic toroid-shaped holes of the TFCD structure act as microlenses due to the intrinsic molecular orientations of each TFCD, which can focus illuminated light. The flat regions between the toroidal holes act as clear windows and do not scatter light. Second, this system uses the advantages of a graded refractive index in LCs as well as periodic microscale arrays. The ordered TFCD structures are generated through the control of themolecular orientations in the LCs on surface modified substrates. The light passing through a TFCD is refracted and focused to the center of the TFCD by the graded refractive index according to the intrinsic LC molecular orientations in a TFCD. Therefore, LC-based TFCD microlenses are optically selective for the direction of polarization of the transmitted light, when used as a photomask. Accordingly, one can obtain a variety of microscale patterns with controlled domain sizes, geometries, and symmetries, by simply adjusting the illumination dose (intensity), the size of the TFCD photomask, the tone of the photoresist, and the direction of polarization of the illuminating light source. To generate the TFCD structure, we used a simple rodlike smectic LC material containing a rigid biphenyl core and a semifluorinated tail group, which was prepared by alkylation of ethyl 4-hydroxyphenylbenzoate with 1H,1H,2H,2H,3H,3H,4H, 4H-perfluorododecyl bromide (Fig. 1a). As reported previously, this material consistently yielded a hexagonal highly ordered structure of TFCDs on the surface of a treated glass substrate. Upon cooling ( 1 8Cmin ) from the isotropic to the SmAphase, ordered TFCD domain arrays were generated over large areas. Because the small LC components had a high mobility and responded rapidly in the smectic phase, the fabrication of TFCD microlens arrays was very fast and simple relative to other soft self-assembly building blocks. We found that the generation of a uniform TFCD large-scale array on a glass substrate required only a few seconds. Figure 1b shows representative polarized optical microscopy (POM) images of the TFCD domains of smectic LCs on a flat PEI-coated glass substrate and reveals the formation of highly ordered periodic TFCDs over a large area. Each small circular domain corresponds to a single TFCD. Close inspection of the POM images of the film formed by the LC revealed that the TFCD were identical in size and were present in a hexagonal array, a characteristic typical of SmA phases under surface anisotropy conditions. [17] Each TFCD produced a characteristic Maltese cross pattern (‘‘microlens’’ region), indicating that the projection of the director field onto the plane of the substrate was radial within the area bounded by the circular base of the TFCD. Outside the circular base (the ‘‘window’’ region), the molecules were vertically aligned to the

Multilevel microstructure fabrication using single-step 3D photolithography and single-step electroplating

Abstract: We developed a useful method to obtain multilevel microstructures simply by single-step 3D photolithography followed by single-step electroplating. By varying UV exposure depth with multiple photomasks in a single-coated conventional thick photoresist, we form multilevel photoresist molds in a single lithography step. After the 3D mold patterning, metal electroplating is performed on it until 3D metallic microstructures are obtained. The critical issue in this process, the exposure depth control, was carefully examined by observing the exposure time versus development characteristic of the resist, in the film thickness range of 40 to 90 micrometer. We proposed a simple method to reproducibly obtain the resist thickness of each level as designed. Using the unique overplating feature in electroplating process, we demonstrated two utmost practical examples: a unified Orifice Plate Assembly (OPA), which has orifice, channel, and reservoirs in a single body, for high-resolution inkjet printhead, and an electroplated Solenoid-type Integrated Inductor (SI 2 ). Both were fabricated using a single-coated 80 micrometer-thick photoresist with only two photomasks, and have many advantages in productivity and performance. This method does not stack planar layer vertically to make 3D microstructures as in the conventional ways, therefore, is a simple, low-cost, and high-yield process. And also, it is IC compatible due to its low process temperature and monolithic process.

System and method for making photomasks

Abstract: The present application is directed a method for preparing a mask pattern database for proximity correction. The method comprises receiving data from a design database. Mask pattern data describing a first photomask pattern for forming first device features is generated. The first photomask pattern is to be corrected for proximity effects in a proximity correction process. A second set of data is accessed comprising information about second device features, wherein at least a portion of the second set of data is relevant to the proximity correction process. The second set of data is manipulated so as to improve the proximity correction process, as compared with the same proximity correction process in which the second set of data was included in the mask pattern database without being manipulated. At least a portion of the mask pattern data and at least a portion of the manipulated second set of data is included in the mask pattern database.