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AssigneeUnity Semiconductor Corporation
InventorsGilles Fresquet, Alain Courteville, Philippe Gastaldo
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A method is provided for inspecting the surface of an object such as a wafer having tridimensional structures, using a confocal chromatic device with a plurality of optical measurement channels and a chromatic lens allowing optical wavelengths of a broadband light source to be focused at different axial distances defining a chromatic measurement range. The method includes a step of obtaining an intensity information corresponding to the intensity of the light actually focused on an interface of the object within the chromatic measurement range at a plurality of measurement points on the object by measuring a total intensity over the full spectrum of the light collected by at least some of the optical measurement channels in a confocal configuration.
A method for inspecting the surface of an object comprising tridimensional structures, using a confocal chromatic device with a plurality of optical measurement channels and a chromatic lens with a strong chromatic aberration allowing different optical wavelengths of a broadband light source to be respectively focused at different axial distances, said different axial distances defining a chromatic measurement range, the method comprising the steps of:
Dependencies are inferred from the claim text.
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Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows: using focussing or collimating elements, e.g. lenses or…
For measuring length, width or thickness: by means of tv-camera scanning
For measuring thickness ; e.g. of sheet material: height gauges
Measuring arrangements characterised by the use of optical techniques: for measuring depth
About 9 years 8 months of term left · ends 29 Jun 2036 (estimated)
The invention relates to a method for inspecting an object such as a wafer, and more particularly for inspecting an object comprising structures such as bumps or micro-bumps.
The field of the invention is, but not limited to, 2D-3D inspection and metrology for semiconductor industry.
Tridimensional structures such as bumps, micro-bumps, solder bumps, copper pilar, copper nails, Re-Distribution Layers (RDL), Under Bump metallization (UBM), metal patterns are more and more widely used for interconnections and other application in the semiconductor industry. With the evolution of the IC packaging, the critical dimensions of these structures tend to decrease and their density on wafers or chips tend to increase. In the same time there is a need for inspection systems capable of inspecting all of these structures at high speed during production, as a few defects are sufficient to render corresponding ICs defective.
The methods according to embodiments of the present invention may be better understood with reference to the drawings, which are given for illustrative purposes only and are not meant to be limiting. Other aspects, goals and advantages of the invention shall be apparent from the descriptions given hereunder.
FIG. 1 illustrates a first mode of realization of confocal chromatic device for carrying out the method of the invention;
FIG. 2 illustrates a second mode of realization of confocal chromatic device for carrying out the method of the invention;
It is well understood that the embodiments described hereinafter are in no way limitative. Variants of the invention can in particular be envisaged comprising only a selection of the features described below in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art. This selection comprises at least one preferred functional feature without structural details, or with only one part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art.
In particular, all the described variants and embodiments can be combined if there is no objection to this combination from a technical point of view.
In the figures, the elements common to several figures retain the same references.