Phase-shift mask

About: Phase-shift mask is a research topic. Over the lifetime, 2088 publications have been published within this topic receiving 18058 citations.

Optical proximity correction using a transmittance-controlled mask (TCM)

Abstract: When small feature delineation is considered using existing exposure tools, special techniques might be needed such as phase shift mask, oblique illumination, top surface imaging, etc. When different types of patterns exist simultaneously or island patterns exist predominantly, optical proximity effect will become more important to be controlled. In this study, six different mask types were prepared and evaluated in view of a pattern fidelity and process latitude for 256 mega bit DRAM's storage node patterns. The masks used for this experiment were conventional transmission mask, serif patterned mask, square patterned Transmittance Controlled Mask (TCM), horizontally rectangular TCM, vertically rectangular TCM, and cross patterned TCM. The cross patterned TCM had three different transmittance on it and was evaluated also. In view of both pattern fidelity and process latitude, cross-TCM showed the best result. The vert-TCM also showed fairly good result. But the worst results always came from the conventional mask. From plane surface area point of view, once serif mask or TCMs are used, the areas always improved ranging from 120% to 145% at the best focus condition compared to the convention mask. There was not so much difference among three different transmittance in view of pattern fidelity and process latitude. As one of candidates for optical proximity correction, since small serif delineation on mask level is not easy for devices with small features such as 1 giga bit DRAM or beyond, TCM is more promising which has much bigger and easily writable gray area.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Phase shift mask and exposure method using the same

Abstract: PROBLEM TO BE SOLVED: To provide a phase shift mask for forming a fine line pattern at a relatively low cost and to provide an exposure method using the mask. SOLUTION: The mask pattern 10 is used for exposing a line pattern in a photolithographic process. The mask pattern 10 is divided into two areas: a center area extended along the center line; and a peripheral area 12 with a constant width W surrounding the center area. The center area is further divided into a plurality of square unit areas 11 arranged in adjacent to each other along the center line, wherein a first phase shifter portion 21 to invert the phase of light is formed in the center of each unit area 11 in such a manner that the phase shifter portion 21 is laid axisymmetric around the center point of each unit area 11 and has 50% area of each unit area 11. A second phase shifter portion 22 to invert the phase of light is formed all over the peripheral area 12. COPYRIGHT: (C)2006,JPO&NCIPI

Inspecting apparatus of mask defect and method for inspecting mask defect

Abstract: PROBLEM TO BE SOLVED: To accurately detect defects or classify defects with respect to inspecting defects in a halftone phase shift mask. SOLUTION: The inspecting apparatus of mask defects to inspect defects in a halftone phase shift mask 2 having a mask pattern including a half-light shielding shifter pattern part and a transmitting opening pattern formed on a transparent substrate is equipped with: irradiating means (1, 3, 5) to irradiate the phase shift mask 2 with inspection light for inspecting defects; first image acquiring means (7, 8) to acquire images of transmitted light through the phase shift mask by irradiation with the inspection light; second image acquiring means (4, 9, 10) to acquire images of reflected light on the phase shift mask 4 by irradiation with the inspection light; and an inspecting means (13) to inspect defects in the phase shift mask 2 by using the images of transmitted light and images of reflected light. COPYRIGHT: (C)2004,JPO

Integrated phase shift measurements for advanced mask etch process control

Abstract: The phase shift effect in Alternating Phase Shift Masks (AAPSMs) and chrome-less phase shift masks is created by etching trenches directly into the quartz substrate. Since the phase shift is critically dependent on the etch depth, the quartz etch process must be tightly controlled. In the absence of an etch stop for the process, an integrated metrology solution is desirable on the mask tech tool. Traditional methods for measuring etch depth or phase shift, such as interferometry, profilometry, AFM, and SEM, are expensive, slow, and/or destructive. In addition, traditional methods cannot measure quartz etch depth without removing the resist and in some cases the chrome mask, making them unsuitable for integration into the etch process. This paper will present measurements of trench depth and phase shift on quartz phase shift mask using the n&k Analyzer 1512-RT. The n&k Analyzer measures reflectance (R) and transmittance (T) from 190-1000nm, which is analyzed according to the Forouhi-Bloomer dispersion relations to simultaneously determine n, k, film thicknesses, trench depth, and phase shift. The measurement is non-destructive and fast, typically taking 2-3 seconds per measurement point. No special test structures are required for the measurement. In addition, the n&k Analyzer can measure quartz etch depth with the chrome mask, ARC layers, and resist still intact. The n&k Analyzer measurements show good correlation with 193nm interferometer measurements, and good repeatability. The small footprint, ease of use, measurement speed, and the ability to measure quartz depth in the presence of chrome and resist make the n&k Analyzer an ideal candidate for integrated metrology applications on mask etch tools for advanced proces control (APC). The Applied Materials' Tetra II phootmask etch system has the unique capability to accommodate integrated metrology modules through the factory interface. Applications of APC with integrated phase shift measurements will be discussed.

Multi-wavelength phase mask

Abstract: Among other aspects, various embodiments include encoding wavelength-based characteristics, in addition to three-dimensional positions, of a plurality of objects of a plurality of different wavelengths directly in an image of the objects.