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AssigneeASML US, Inc.
InventorsScott D. Coston, James G. Tsacoyeanes
Estimating the term…
A system and method for improving line width control in a lithography device are presented. Electromagnetic energy is emitted from an illumination source and passed through illumination optics. The illumination optics include a partial coherence adjuster having a first and second optical element. The first optical element is used for changing the partial coherence of incident electromagnetic energy in a predetermined manner to compensate for horizontal and vertical line biases of the lithography device. The second optical element is used for changing the angular distribution of electromagnetic energy incident upon the first optical element. Together, the two optical elements are used to vary the partial coherence of the electromagnetic energy emitted by the illumination source, as a function of illumination field position, and improve line width control. Adjustment of the second optical element allows for correction of time-dependant line width variances.
A lithography system, comprising:
A method for controlling the angular distribution of electromagnetic energy in a lithography device as a function of field position, the method comprising the steps of:
An apparatus for improving line width control in a lithography device, comprising:
Dependencies are inferred from the claim text.
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Mask illumination systems: illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane;…
Mask illumination systems: illumination system adjustment, e.g. adjustments during exposure or alignment during assembly of illumination system
Monitoring the printed patterns: dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
Photomechanical production of textured or patterned surfaces
Term end not estimated
This invention relates to photolithography. More particularly, it relates to line width control in a photolithography device.
Lithography is used in the manufacture of semiconductor chips. Lithography, or more particularly photolithography, involves projecting one or more images of a reticle or semiconductor circuit mask onto a photosensitive substrate of a wafer. The wafer is then processed to form one or more circuits. As the art of semiconductor chip manufacturing progresses and the size of semiconductor devices become smaller, there is a need for improving line width control in photolithography devices.
Large semiconductor chips are typically manufactured using a step-and scan lithography device. A step-and-scan lithography device operates by scanning a typically rectangular illumination field defined by an illumination system over a reticle having a circuit pattern thereon. A step-and-scan lithography device is used to manufacture large semiconductor chips, in part, because the size of a semiconductor chip that can be manufactured using a step-and-scan lithography device is not limited to the size of the device's projection optics.
The present invention is described with reference to the accompanying figures. The accompanying figures, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art to make and use the invention. In the figures, like reference numbers indicate identical or functionally similar elements. Additionally, the leftmost digit or digits of a reference number identify the figure in which the reference number first appears.
FIG. 1 illustrates an example lithography device that incorporates the invention.
FIG. 2 illustrates how to measure the partial coherence of the lithography device of FIG. 1.
The present invention provides a system and method for improving linewidth control in a lithography device. As will be apparent from the detailed description herein, the present invention is particularly well adapted for use with a step-and-scan lithography device.
In the description that follows, reference will be made in detail to present embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the present embodiments, it will be understood that they are not intended to limit the invention to just these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which can be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, upon reading this disclosure, that the present invention can be practiced without these specific details. In other instances, well-known structures and devices are not described in detail in order to avoid obscuring aspects of the present invention.
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