JP3752483B2 - Fine pattern shape measurement system and shape measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for measuring the shape of a fine pattern formed in a semiconductor device such as a semiconductor memory or an integrated arithmetic circuit.
[0002]
[Prior art]
In order to achieve a high degree of integration of semiconductor devices, the line width of wiring patterns has been remarkably reduced. In addition, a new resist material used for exposing light having a short wavelength based on ArF (argon fluoride) to form a fine pattern has been developed (see, for example, Patent Document 1). On the other hand, as a technique for measuring the fine width of a pattern formed on a semiconductor device, a length measuring SEM (scanning) that detects secondary electrons and reflected electrons generated by irradiating an electron beam and measures the width using the signal intensity. (Electron microscope) is known (for example, see Patent Document 2).
[0003]
However, the length measurement SEM has a problem that even if a fine width can be measured, if the resist material is irradiated with an electron beam, the width becomes narrow.
[0004]
[Patent Document 1]
JP 2000-241964 A (page 3)
[Patent Document 2]
JP 2001-272219 A (5th page, FIG. 5)
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a fine pattern shape measurement system and a shape measurement method capable of measuring the shape of a semiconductor device without changing the size of the fine pattern.
[0006]
[Means for Solving the Problems]
In an embodiment of the present invention, a test pattern area is provided in a scribe line area provided for dividing each semiconductor device on a wafer, which is composed of a measurement mechanism by electron beam irradiation and a measurement mechanism by a light beam. The pattern region is provided with a plurality of patterns having a plurality of widths that can be measured by a light beam created in the same manufacturing process as the pattern of the semiconductor device, and the semiconductor device is a dummy having the same width created in the same manufacturing process as the pattern. A pattern is provided, the width of the test pattern region is measured by irradiating the pattern with a light beam, and the width is measured by irradiating an electron beam to determine the amount of change in the width. Measure the width by irradiating with an electron beam, and use the amount of change in width caused by the irradiation of the electron beam previously obtained. And estimates the width of the pattern of a semiconductor device by calculating the width of before the irradiation.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a semiconductor device inspection apparatus showing an embodiment of the present invention.
[0008]
The semiconductor device inspection apparatus includes a portion that irradiates the wafer 100 with an electron beam and a portion that irradiates the wafer 100 with light. Wafer 100 is mounted on stage 102 and can reciprocate between both as indicated by arrow 114. An interlock 115 is provided between the two so as to maintain the degree of vacuum in the portion where the electron beam is irradiated onto the wafer 100.
[0009]
The portion that irradiates the wafer 100 with the electron beam mainly includes an electron source 103, an electron beam extraction electrode 104, a diaphragm 105 for shaping the electron beam, a condenser electromagnetic lens 106 and an objective electromagnetic lens 107 for converging the electron beam, and an electron beam. Is deflected to scan on the wafer 100 or to irradiate non-irradiation, and secondary electrons and reflected electrons 109 generated from the wafer 100 by scanning of the electron beam are detected by the detector 101 to perform image processing. The apparatus 116 generates an image signal and displays the image on the monitor 117.
[0010]
On the other hand, the portion that irradiates light to the wafer 100 irradiates the wafer 100 with the light beam 112 generated by the light beam source 110, detects the light 113 with the detector 111, and generates an image signal with the image processing device 116. The image is displayed on the monitor 117.
[0011]
As an example of a method for measuring the height of a pattern using a light beam, a method using scatterometry as described in JP-A-8-255751 is known.
[0012]
A procedure for measuring a three-dimensional shape of a fine pattern using the above-described semiconductor device inspection apparatus will be described below.
[0013]
FIG. 2 is a top view of the wafer 100 and its details. A large number of semiconductor chips 201 are formed on the wafer 100. A scribe region is provided between the semiconductor chips 201, and the semiconductor chip is completed by cutting in this region. A test pattern area 202 and a test pattern area 203 are provided in the scribe area. The pattern of the region is created by the same manufacturing process as the representative pattern 206 in the main region 204 to be inspected of the semiconductor chip 201. In addition, the dimensions, in particular, the widths of the test pattern region 202 and the test pattern region 203 are a plurality of widths that can be measured by irradiation with a light beam.
[0014]
A dummy pattern 205 is provided in the main region 204 of the semiconductor chip 201 together with the pattern 206. The dummy pattern 205 is created in the same manufacturing process as the pattern 206 and has the same width.
[0015]
FIG. 3 is a flowchart showing the procedure of pattern shape measurement.
[0016]
First, in step 302 of FIG. 3, the pattern of the test pattern area 202 by the light beam is measured, its width is obtained, and stored in the memory. Further, patterns having different widths in the same test pattern region 202 or another test pattern region 203 are measured, and the widths are obtained and stored in the memory.
[0017]
Next, in step 303 of FIG. 3, the electron beam is irradiated to the pattern measured in step 302 of the test pattern region 202, and the width of the pattern is measured and stored in the memory. This width dimension indicates the dimension after being thinned by irradiation with the electron beam. Similarly, patterns having different widths in the same test pattern region 202 or another test pattern region 203 are measured, and the width is obtained and stored in the memory.
[0018]
Next, at step 304, as shown by an arrow 309 in FIG. 3, the amount of change in the test pattern is calculated from the measurement data by the light beam and the measurement data by the electron beam. The width of the test pattern is a size that can be measured with a light beam. Specifically, when the width dimension data measured by light beam irradiation is a and the width dimension data measured by electron beam irradiation is b by a computer in the image processing apparatus 116, the value of b / a is set to the image processing apparatus 116. Is stored in a memory (not shown).
[0019]
Next, at step 305, the dummy pattern 205 of the semiconductor chip 201 shown in FIG. 2 is irradiated with an electron beam, and its width c is measured. The width of the dummy pattern 205 has the same fine dimensions as the representative pattern 206 and cannot be measured with a light beam.
[0020]
Next, using the result obtained in step 304 as indicated by an arrow 310, in step 306, the width d of the dummy pattern 205 before the electron beam irradiation is calculated and estimated. That is, it is possible to obtain d = c × (a / b) using the light beam and electron beam variation b / a stored in the memory in step 304. Although this width dimension is an estimated value of the dummy pattern 205, it has the same width created in the same manufacturing process as the representative pattern 206 before the electron beam irradiation. Can be considered.
[0021]
In step 307, the estimated width or the shape of the pattern having the width is displayed on the monitor 117.
[0022]
As described above, the width of the test pattern provided in the scribe area of the wafer is measured and stored with the light beam and the electron beam, the amount of change in the width is calculated, and the dummy pattern of the semiconductor chip is measured with the electron beam. By measuring the width and estimating the width before electron beam irradiation, the shape of the fine pattern of the semiconductor device can be measured.
[0023]
In this example, the test pattern created in the scribe area is intended for line-and-space, which is a repetition of elongated linear peaks and valleys. The shape can be measured.
[0024]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a fine pattern shape measuring system and a shape measuring method capable of measuring the shape of a semiconductor device without changing the dimension of the fine pattern.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a semiconductor device inspection apparatus.
FIG. 2 is a top view of wafer 100 and its details.
FIG. 3 is a flowchart showing a procedure for measuring the shape of a pattern.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 100 ... Wafer, 116 ... Image processing apparatus, 201 ... Semiconductor chip, 202, 203 ... Test pattern area | region, 205 ... Dummy pattern.

Claims (4)

The light beam is formed on a plurality of patterns in a test pattern area provided in a scribe line area provided to divide a plurality of semiconductor devices on a wafer. And a storage unit for storing the width of the pattern obtained by irradiating the electron beam and the width of the pattern obtained by irradiating the electron beam, and calculating a change in the width of the pattern before and after the electron beam irradiation And a calculation unit for calculating the width of the dummy pattern before irradiation with the electron beam from the width obtained by irradiating the dummy pattern provided on the semiconductor device with the electron beam and the amount of change. A fine pattern shape measurement system. 2. The fine pattern shape measurement system according to claim 1, wherein the pattern of the test pattern region is created by the same manufacturing process as the pattern of the semiconductor device, and the width thereof can be measured by the light beam. Irradiate a plurality of patterns in a test pattern area provided in a scribe line area provided to divide a plurality of semiconductor devices on a wafer, measure and store the width of the pattern, and irradiate an electron beam Then, the width of the pattern is measured and stored, and the amount of change in the pattern width is calculated and stored. From the width obtained by irradiating the dummy pattern of the semiconductor device with the electron beam and the amount of change A method for measuring the shape of a fine pattern, wherein the width of the dummy pattern before irradiation with an electron beam is obtained. 4. The fine pattern shape measuring method according to claim 3, wherein the pattern of the test pattern region is created by the same manufacturing process as the pattern of the semiconductor device, and the width thereof can be measured by the light beam.

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