Correction masks for thickness uniformity in large-area thin films

Abstract

Experimental results from the emission of vapor sources are considered in designing correcting diaphragms to achieve a uniform thickness distribution during evaporation of thin films mounted on large-area substrate holders, in different geometric configurations.

Optimization of thickness uniformity of optical coatings on a conical substrate in a planetary rotation system

“…According to Knudsen's laws [6,7], the elementary thickness of a growing film at a given position of the substrate surface can be expressed as…”

“…Conventionally, a rotating or fixed shadowing mask is employed in a simple or planetary rotation system in a coating machine to selectively obstruct the deposition plume profile, and therefore optimize the thickness uniformity of optical coatings deposited upon optics [6][7][8][9][10][11]. Most recently, a gyro and modified planetary rotation motion without shadowing mask have been employed to achieve high degree of thickness uniformity with thermal evaporation (TE) and ion beam sputtering coating machines, respectively [12,13].…”

“…Currently, the model for the design of a fixed mask, no matter in a simple or planetary rotation system, has achieved great success [7,8,10]. Currently, the model for the design of a fixed mask, no matter in a simple or planetary rotation system, has achieved great success [7,8,10].…”

Uniformity Masks Design Method Based on the Shadow Matrix for Coating Materials with Different Condensation Characteristics

“…For one thing, the design procedure is usually a laborious process because the shadow effects of masks on substrates are inexplicit. This makes the mask design an inconvenient process that usually involves complex mathematic algorithms, such as the analytical method developed by Villa et al [6] for flat and curved substrates with simple rotation movement and the iterative approach adopted by Bauer et al [7] or the initialize-and-mending design procedure proposed by both Liu et al [8] and Guo et al [9] for curved substrates with planetary rotation motion. For another thing, mask design methods used in previous works are not effective in the cases where coating materials used in the same deposition process have different values of condensation parameters, because the model popular used to describe the deposition rate in these methods is a simplified model which does not take the condensation characteristics [10] of coating materials into consideration.…”

Masking technique for coating thickness control on large and strongly curved aspherical optics

“…Many masking techniques have been developed over the past ten years. Shadowing masks [2,3] or oscillating multiaperture masks [4] were used to enhance thickness uniformity. Masks in rotation and/or in translation were applied to manufacture linear variable interference filters [5,6].…”