KR20070052054A - Lithography apparatus for semiconductor - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor lithographic apparatus, wherein the semiconductor lithographic apparatus according to the present invention connects an optical CD (Critical Dimension) measuring device within a lithographic apparatus to easily detect defects occurring in a wafer in a lithography process, and A defect monitoring system of a lithographic apparatus which can improve the efficiency of a lithography process by advancing a defect measuring process to an inline process.

Description

Semiconductor lithography apparatus {LITHOGRAPHY APPARATUS FOR SEMICONDUCTOR}

1 is a cross-sectional view of an emulsion lithographic apparatus.

2 is a cross-sectional view showing the generation of bubbles in an emulsion lithographic apparatus.

3 and 4 are schematic diagrams showing the principle of the optical CD measuring device.

5 is a schematic diagram illustrating a semiconductor lithographic apparatus according to the present invention.

6 is a schematic diagram illustrating a semiconductor lithographic apparatus according to a second embodiment of the present invention.

7 is a lithographic process progression according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor lithographic apparatus, wherein the semiconductor lithographic apparatus according to the present invention connects an optical CD measuring apparatus in a lithographic apparatus to facilitate detection of defects occurring in a wafer in a lithography process, and performs a lithography process and a defect measuring process. By going to an inline process, it is related with the defect monitoring system of the lithographic apparatus which can improve the efficiency of a lithographic process.

As semiconductor devices have been highly integrated, defects occurring on the wafer after the lithography process may cause pattern abnormalities, lower CD uniformity, and lower yields.

Types of lithographic apparatuses include lithographic apparatuses using air as an exposure medium and emulsion lithography apparatuses using liquid as an exposure medium. In this case, since the lithography apparatus performs the lithography process in a liquid state, defects such as bubbles or water marks are generated on the wafer.

1 is a cross-sectional view of an emulsion lithographic apparatus.

Referring to FIG. 1, there is shown a lithographic apparatus including an emulsion portion 40 in which a liquid is contained between a projection lens portion 20 and a wafer stage 30. The emulsion part 40 includes a liquid supply part 50 and an outlet part 60, and the lithography process of the emulsion method can maximize the resolution, but since the liquid directly contacts the wafer 10, the probability of defect occurrence is increased. There is a problem that increases.

2 is a cross-sectional view illustrating the occurrence of bubbles in an emulsion lithography apparatus.

Referring to FIG. 2, after performing a lithography process with an emulsion lithography apparatus, defects such as bubbles or watermarks 70 by a liquid have occurred on the wafer 10.

Equipment that detects such defects include CD-SEM (Critical Dimension-Strategic Enterprise Management) or Bright Fields Inspection (CD-SEM) equipment, but CD-SEM is measured using an electron beam (E-Beam) Only a narrow image can be measured, so there is a limit to finding all defects on the wafer. In addition, since the electron beam acts to slide the photosensitive film in the lithography process using ArF, there is a problem that may cause abnormalities in the pattern. Brightfield inspection equipment is measured using a light source with a relatively low wavelength, so there is no problem affecting the photoresist film, but it can only detect defects and perform a process of verifying using CD-SEM after measuring defects. Therefore, it takes a long time to measure a single wafer, there is a problem that the process yield is lowered.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and includes an optical CD measuring apparatus in a lithography apparatus that can efficiently analyze the entire wafer area and can efficiently improve the lithography process. In this case, the object of the present invention is to provide a semiconductor lithography apparatus that can efficiently detect defects in a wafer and shorten processing time by designing a detection light source using an optical CD measuring device so that the light source used in the wafer alignment system can be used as it is. It is done.

The present invention is to achieve the above object, the semiconductor lithographic apparatus according to the present invention is

A lithographic apparatus comprising a light source unit, a reticle stage, a projection lens unit, and a wafer stage,

Measuring an alignment state of the wafer placed on the wafer stage before the lithography process is performed, an illumination case for producing a light source used for the alignment process and irradiating the wafer, and measuring the alignment state of the wafer using the light source An alignment system including an alignment block of any one selected from an off-axis method and a through the lens method;

And an optical CD measuring device connected with the alignment block of the alignment system to detect defects of the wafer using the alignment system in an in-line process after the lithography process is performed.

Hereinafter, a semiconductor lithography apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, an optical CD metrology is first introduced as a method of measuring defects in a wafer.

3 and 4 are schematic diagrams showing the principle of the optical CD measuring apparatus.

Referring to FIGS. 3 and 4, when the light source is reflected on the wafer 160 and then reflected, the path is reflected. When a defect 175 occurs in the pattern as shown in FIG. 4, an abnormality occurs in the path of the irradiated light source. It is easy to know. Therefore, the optical CD measuring apparatus has an advantage of monitoring the entire area of the wafer 160 in a short time by increasing the number of light sources. In addition, since the optical CD measuring apparatus can be used to measure the CD of the pattern formed on the wafer, there is an effect that the subsequent CD measurement time can be shortened when viewed throughout the lithography process.

5 is a schematic diagram illustrating a semiconductor lithographic apparatus according to a first embodiment of the present invention.

Referring to FIG. 5, a light source unit 100 for irradiating a light source used in a lithography process is positioned at an upper portion thereof, and a reticle stage 110, a projection lens unit 120, and a wafer stage 130 are sequentially disposed below.

Here, the lithographic apparatus according to the present invention includes alignment systems 140 and 150 for measuring the alignment of the wafers 160 placed on the wafer stage 130. The alignment system 140, 150 includes an illumination case 150 for irradiating a light source used in the alignment process and an alignment block 140 for measuring the alignment state of the wafer 160 using the light source. The apparatus further includes an optical CD measuring apparatus 200 that detects a defect of a wafer on which an exposure process is performed using the alignment systems 140 and 150.

In this case, an Off-Axis method or a TTL method may be used as the alignment system, and the alignment system illustrated in FIG. 5 is according to an embodiment of the present invention and is based on an alignment system of TTL (Through The Lens) method. Hereinafter, the principle of operating the optical CD measuring device 200 using the alignment system according to the present invention will be described in detail.

The illumination case 150 of the alignment system includes a source portion 105 forming a light source used in the alignment process, and a reflecting portion guiding the light source. At this time, it is preferable to use a helium-neon light source (633 nm) as a kind of light source, and this light source is also used in the optical CD measuring device.

The wafer on which the lithography process is completed is left in the lithographic apparatus, and the light source formed in the illumination case 150 is irradiated to the wafer 160 through a predetermined path. Here, the first path of the light source is formed through the first reflecting part 115 and the third reflecting part 135 in the illumination case 150 via the fourth reflecting part 155 of the projection lens part 120. The second path is formed in the second reflector 125 via the fifth reflector 145 and the fourth reflector 155. The light sources irradiated onto the wafer 160 are collected into the alignment block 140 and transmitted to the optical CD measuring apparatus 200 through the sixth reflector 165 and the detector 170 in the alignment block 140 and the wafer 160. It is a signal to analyze whether the patterns formed in the defect.

6 is a schematic diagram illustrating a semiconductor lithographic apparatus according to a second embodiment of the present invention.

FIG. 6 illustrates a lithographic apparatus including an off-axis alignment system of the lithographic apparatus described above, wherein a detector 170 of an alignment block 140 and an optical CD measuring apparatus 200 are connected to each other, thereby causing a defect in a lithography process and a wafer. It shows that the detection process can be performed in one process step.

7 is a process lithography process in accordance with the present invention.

Referring to FIG. 7, in the lithographic apparatus according to the present invention, the lithographic apparatus 180 and the optical CD measuring apparatus 200 perform a lithography process and a defect detection process mutually organically. And performing a lithography process again after performing the step.

In addition, the lithographic apparatus 180 according to the present invention also includes a case of an emulsion lithography apparatus capable of improving a lithography processing capability by inserting a liquid between the projection lens unit and the wafer stage, and including the lithographic apparatus 180 and the optical CD. The process by the measuring apparatus 200 and the feedback control unit 190 are all performed in-line.

As described above, in the semiconductor lithography apparatus according to the present invention, in order to easily detect defects occurring in the wafer in the lithography process, an optical CD layering apparatus is connected in the lithography apparatus, and the lithography process and the defect measurement process are performed in an inline process. Thereby, the efficiency of a lithography process can be improved. In addition, since it is not necessary to separately provide a light source source device for detecting defects, it is possible to reduce equipment costs and shorten the defect detection time.

In addition, a preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be able to various modifications, changes, substitutions and additions through the spirit and scope of the appended claims, such modifications and changes are the following claims It should be seen as belonging to a range.

Claims (5)

A lithographic apparatus comprising a light source unit, a reticle stage, a projection lens unit, and a wafer stage, Alignment of the wafer placed on the wafer stage before the lithography process is performed, including an illumination case for producing a light source used for the alignment process and irradiating the wafer to the wafer, and an alignment block for measuring the alignment state of the wafer using the light source. An alignment system for measuring status; And And an optical CD measuring device coupled with the alignment block of the alignment system to detect defects of the wafer using the alignment system in an in-line process after the lithography process is performed. The method of claim 1, The semiconductor lithographic apparatus is an emulsion lithographic apparatus, And an emulsion portion between the projection lens portion and the wafer stage. The method of claim 1, The alignment system is a semiconductor lithography apparatus, characterized in that any one selected from Off-Axis method and Through The Lens (TTL) method. The method of claim 1, And the optical CD measuring device uses the same light source as the light source used in the alignment system as the defect measuring source. The method of claim 1, And the optical CD measuring apparatus further comprises a feedback control unit for reworking when a defect of a wafer is detected.

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