摘要:

Antireflective MoSi (AR‐MoSi) photomasks which are produced by applying a thin layer of MoSi oxide directly over the conventional MoSi layer on a quartz substrate has been developed. The thin layer of MoSi oxide is deposited using magnetron dc sputtering. The reflectivity and optical density of the thin layer are not affected by H2SO4at 120 °C. The layer reflectivity is changed by varying the oxygen partial pressure ratio in argon gas and the layer thickness. To obtain minimum reflectivity, the mechanism of antireflection was studied by using a model of multipath interference with absorption of light. Experimental and theoretical results are in good agreement and show a minimum reflectivity of 6.4% for a 40–60 nm thick MoSi oxide layer. By exposing the photomask, it was found that the AR‐MoSi photomask has practicable resolution performance comparable to conventional photomasks.

ISSN:1071-1023    

DOI:10.1116/1.586042

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

ISSN:1071-1023    

DOI:10.1116/1.586043

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.586045

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

ISSN:1071-1023    

DOI:10.1116/1.586047

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

The essentials of proximity x‐ray lithography (XRL) have been established and successful alternative implementations have been demonstrated in academic and industrial laboratories worldwide. Results continue to show that XRL can provide simpler and more robust processes than optical or electron beam alternatives. And it is widely accepted that this becomes more true as lithographic dimensions shrink. So why do we still await the introduction of the first commercial use of XRL? Use of a new technology requires its either attaining the unattainable or excelling at cost/performance. For near term application, XRL must leap the latter hurdle. While most concede the superior robustness of XRL to normal process variation, popular lore has it that availability or an adequate infrastructure limits XRL becoming a process of choice. We discuss the current state of XRL against this competitive challenge and project progress forward. In so doing, we find that XRL is now approaching a critical crossroad. While optical approaches struggle to demonstrate technical realization and electron beam approaches are losing ground in the pixel per chip per second race, XRL’s challenge is to mature its infrastructure sufficiently to attract proponents eager to make it the process of choice. The pace of XRL efforts leads us to the conclusion that XRL can be the process of choice for 250 nm applications, most probably beginning with 256 Mb DRAM or NVRAM.

ISSN:1071-1023    

DOI:10.1116/1.586048

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Complex computer generated phase holograms (CGPHs) have been fabricated in polymethyl methacrylate (PMMA) by partial exposure and subsequent partial development. The CGPH was encoded as a sequence of phase delay pixels and written by e‐beam (JEOL JBX‐5DII), a different dose being assigned to each value of phase delay. Following carefully controlled, partial development, the pattern appears, rendered in relief, in the PMMA which then acts as the phase‐delay medium. The exposure dose was in the range 20–200 μC/cm2, and very aggressive development in pure acetone led to low contrast. This enabled etch depth control to better than ±20 nm corresponding to an optical phase shift in transmission, relative to air, of ±λvis/60. That result was obtained by exposing isolated 50 μm square patches and measuring resist removal over the central area where the proximity effect dose was uniform and related only to the local exposure. For complex CGPHs with pixel size of the order of the proximity radius, the patterns must be corrected for proximity effects. In addition, the isotropic nature of the development process will produce sidewall etching effects. The devices fabricated were designed with 16 equal phase steps per retardation cycle, were up to 3 mm square, and consisted of up to 10 million 0.3–2.0 μm square pixels. Data files were up to 60 Mb long and exposure times ranged to several hours. No sidewall etch corrections were applied to the pattern and proximity effects were only treated approximately. A Fresnel phase lens was fabricated that had diffraction limited optical performance with 83% efficiency.  

ISSN:1071-1023    

DOI:10.1116/1.586049

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Anisotropic reactive ion etching of deep Si structures (≥8 μm), planarization of deeply stepped topographies, and multilayer resist processes have been developed for fabrication of silicon IR binary optics devices. The effect of adding O2and C2F6to the SF6feed gas on sidewall profile and etch selectivity (Si:photoresist) has been determined. Vertical profiles, without mask undercutting or surface texturing, and high etch selectivity (≥5:1) have been obtained with a 74% SF6–26% O2mixture. We have successfully fabricated 8‐μm deep Si optics with 16 phase levels and eight‐level structures with a total depth of 14 μm in Si.

ISSN:1071-1023    

DOI:10.1116/1.586050

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

This article reports on progress in the fabrication by e‐beam lithography of high resolution, continuous‐relief microstructures for integrated optical applications in the visible and near infrared. The microstructures are designed for subsequent replications from an electroformed metal shim by embossing into polymer films on glass. The objective of this work is to fabricate complete integrated optical devices and circuits by low‐cost embossing or casting replication technology.

ISSN:1071-1023    

DOI:10.1116/1.586051

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Direct write e‐beam lithography and reactive ion etching was used to fabricate square‐wave gratings in quartz substrates which serve as pure phase masks in the near‐field holographic printing of gratings. This method of fabricating these masks extends the flexibility of the printing technique by allowing both abrupt phase shifts as well as multiple grating pitches to be simultaneously printed from a single contact mask. Grating masks with periods in the 235–250 nm range have been produced and measured to be within 0.15 nm of the design period. Transmitted and diffracted beam powers have also been measured for various duty cycles and etch depths and are shown to be important parameters for ‘‘balancing’’ these interfering beams. Simple scalar diffraction modeling is used to qualitatively examine the dependence of diffraction on grating parameters, but the need for a more comprehensive modeling is illustrated. Prototype masks have been used to produce grating patterns on InP substrates using two different ultraviolet illumination sources: an argon ion laser and a conventional mercury lamp.

ISSN:1071-1023    

DOI:10.1116/1.586052

出版商:American Vacuum Society    

年代:1992

数据来源: AIP

摘要:

Chemically amplified positive resist formulations have been shown to exhibit high photospeed, excellent resolution, and tolerance to process parameters such as softbake, exposure, postexposure bake, developer concentration, and temperature. Many chemically amplified positive resists, however, adhered poorly to some substrates (e.g., Si3N4), required considerable optimization of the etch process to achieve desired etch selectivities and were sensitive to airborne basic contaminants. Many chemically amplified negative resists while not as sensitive to contaminants in the clean room air, show retrograde wall angles especially on antireflection coatings, demonstrate poor latitude in defining contact holes and are difficult to strip after pattern transfer steps. In this article we discuss our efforts toward designing new deep‐ultraviolet (UV) matrix resins and resist formulations as well as efforts toward defining an optimized process. The optimized resist process demonstrates 0.25 μm line and space (L/S) and 0.30 μm contact hole resolution in 0.8 μm thick resist films with a GCA deep‐UV exposure tool. The resist also exhibits excellent adhesion on most semiconductor substrates (e.g., Si, polysilicon, SiO2, Si3N4), thermal stability to at least 140 °C, an order of improvement in postexposure delay latitude over that of CAMP1 (polyt‐butoxycarbonyloxystyrene‐sulfone formulated with photoacid generators) and etch selectivity comparable to that of novolac based resists. In addition, the polymers developed were designed for ease of manufacture with regard to reproducibility, low metal concentration, and cost.

ISSN:1071-1023    

DOI:10.1116/1.586053

出版商:American Vacuum Society    

年代:1992

数据来源: AIP