Semiconductor device manufacturing: process – With measuring or testing
Reexamination Certificate
2003-03-12
2004-09-28
Dang, Phuc T. (Department: 2818)
Semiconductor device manufacturing: process
With measuring or testing
C438S018000
Reexamination Certificate
active
06797529
ABSTRACT:
BACKGROUND OF THE INVENTION
In producing devices by combining very fine thin film patterns such as semiconductor devices and liquid crystal display devices, this invention relates to a measuring/monitoring apparatus for measuring a film formation condition and a processing condition in a film formation processing for forming a thin film, a planarization processing for planarizing the resulting thin film, an etching processing for forming very fine patterns on the thin film, etc, a film thickness/etching depth measuring apparatus having the measuring/monitoring apparatus assembled therein, a measuring/monitoring method using these apparatuses, and a film formation/processing method.
In a film formation processing, a planarization processing and a very fine pattern formation processing that are employed for producing semiconductor devices or liquid crystal display devices, it is very important to precisely determine a change of a film thickness and a condition of progress of the very fine pattern formation processing, and to execute a series of processing as designed originally. An interference method that utilizes interference of light has been broadly used to measure a film thickness and a progress condition of a very fine pattern processing during these processing. JP-A-8-292012, for example, describes an etching end point detector that detects the end point of the very fine pattern formation by utilizing interference as a prior art technology.
JP-A-11-153416 discloses a method of measuring a thickness of a film formed on a substrate by interference. Also, JP-A-7-4921 discloses a method of measuring a film thickness in a planarization processing of a substrate surface. This reference describes measurement of a film thickness during polishing of a semiconductor wafer by the steps of irradiating measuring light having a wavelength that transmits through the substrate during the film thickness measurement, and measuring the thickness of a thin film on the basis of reflected light of measuring light that is reflected after transmitting through the substrate. Further, JPA-10-111186 teaches to improve accuracy of temperature measurement by radiated infrared light by using a filter.
However, these prior art technologies are not yet free from the following problems. The etching end point detector disclosed in JP-A-8-292012 measures a surface condition of a processed substrate through a processing chamber. Since the condition inside the processing chamber and the condition of an inner wall surface of an inspection window for inspection change in the course of repetition of the processing, and this change affects the measurement result. In consequence, high precision measurement and monitoring are difficult.
The method of measuring the processing condition of the surface of the processed substrate from its back as described in JP-A-11-153416 and JP-A-7-4921 cannot easily detect with high accuracy reflected light from the substrate surface for measuring the condition of the substrate surface because the influences of reflected light from the substrate surface are great.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a measuring/monitoring apparatus capable of selectively detecting reflected light from a substrate surface for measuring the condition of the substrate surface, and capable of precisely measuring the condition of the substrate surface in order to measure a film thickness or an etching depth without influences of a processing condition and an internal condition of a processing chamber.
It is another object of the present invention to provide a film formation/etching measuring apparatus having a high precision measuring/monitoring apparatus of a substrate surface assembled therein, and a high precision film formation method by using such measuring/monitoring apparatuses. The present invention aims at accomplishing either of these objects.
To accomplish the objects described above, a first feature of the present invention resides in a measuring apparatus comprising irradiation means for irradiating measuring light from the back of a substrate in such a fashion that measuring light can be totally reflected from both first and second surfaces formed on the surface side of the substrate, and measurement means for causing reflected lights of measuring light irradiated by the irradiation means and reflected from the first and second surfaces to interfere with each other, and thus measuring a distance between the first and second surfaces.
A second feature of the present invention for accomplishing the objects described above resides in a measuring apparatus for measuring a film thickness of a film formed on a surface of a substrate or a depth of a processed surface processed on a substrate surface by optical interference means, comprising irradiation means capable of irradiating measuring light from the back of the substrate in such a fashion that measuring light is totally reflected from both an interface between a film formed on the substrate surface and the substrate and a processed surface of the substrate or a film surface, and measurement means for measuring a film thickness or a processing depth by causing reflected light from the interface and reflected light from the processing surface or the film surface to interfere with each other.
A third feature of the present invention for accomplishing the objects described above resides in a measuring apparatus for measuring a film thickness of a film formed on a surface of a substrate or a depth of a processed surface processed on a substrate surface by optical interference means, comprising irradiation means capable of irradiating measuring light from the back of the substrate in such a fashion that measuring light is totally reflected from both an interface between a film formed on the substrate surface and the substrate, and a processed surface of the substrate or a film surface, and measurement means for measuring a film thickness or a processing depth by causing reflected light from the interface and reflected light from the processing surface or the film surface to interfere with each other, wherein the irradiation means can irradiate irradiation light at different angles of incidence to the back of the substrate and can vary the angle of incidence of irradiation light so that an optical path difference of irradiation light transmitting through the substrate is greater than the wavelength of incident light, and an optical path difference due to the film thickness of the film or the processing depth as an object of measure is smaller than the wavelength of incident light.
A fourth feature of the present invention for accomplishing the objects described above resides in a measuring apparatus for measuring a film thickness of a film formed on a substrate surface by optical interference means, comprising means for irradiating from the back of the substrate both measuring light under a condition where measuring light is totally reflected on the surface of the film formed on the substrate surface, and measuring light under a condition where measuring light is totally reflected by an interface between the film and the substrate, and means for measuring the film thickness by causing reflected light from the surface of the film and reflected light from the interface between the film and the substrate to interfere with each other, and thus measuring the film thickness.
In each of the features described above, the irradiation means can irradiate measuring length having a plurality of measuring light, and the measurement means preferably measures the film thickness or the processing depth from the interference result for each wavelength.
A fifth feature of the present invention for accomplishing the objects described above resides in a thin film formation apparatus for forming a thin film on a substrate, comprising irradiation means for irradiating, from a back of a substrate, measuring light in such a fashion that measuring light is totally reflected by an interface between a film formed on a substrate sur
Otsubo Toru
Usui Tatehito
Antonelli Terry Stout & Kraus LLP
Dang Phuc T.
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