JPH0669110A - Electron beam pattern lithography system - Google Patents

Abstract

PURPOSE:To increase production yield by enhancing connection accuracy and registration accuracy of a pattern in registration lithography. CONSTITUTION:In the pattern lithography system where a predetermined pattern is formed on the surface of a sample 14 by controlling an electron beam projected from an electron gun 2 through a deflection system, an alignment mark 16 is drawn under a state where an electron beam 15 is deflcted by a maximum amount or an arbitrary amount during drawing work of a first layer pattern. The alignment mark 16 is detected through a signal processing system 19 while carrying out deflecting operation of the electron beam 15 prior to drawing start of a second layer pattern and the detection results are fed through a system control computor 17 back to a deflection distortion correcting amount for a deflection control system 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electron beam drawing technique,
In particular, the present invention relates to a technique that is effective when used to form a predetermined pattern on a sample.

[0002]

2. Description of the Related Art With the miniaturization of semiconductor devices, highly accurate overlay drawing is required. Also, in the production of a reticle, which is the original plate of lithography, a phase shift technique (a chrome layer on a quartz plate and a resist layer on this chrome layer are applied to improve the resolution, and the resist layer is formed according to the pattern shape. Is partially removed by etching and lithographic techniques, the resist layer is covered with a shifter of SOG, and a drawing process) is being introduced. Overwriting is indispensable in the direct wafer writing including the writing by the phase shift technique.

Conventionally, a step of forming a first layer having a first pattern on a surface of a sample by a lithographic technique and an etching technique, and a step of forming a first layer on the layer based on the first layer by the lithographic technique and an etching technique. When pattern formation is performed with a step of forming a second layer having a second pattern, desired alignment marks are provided in advance at four corners or around the sample in order to maintain overlay accuracy, or the first alignment is performed. Drawing is performed by drawing overlay marks at the time of pattern formation, and detecting with an electron beam using these marks.

[0004]

According to the study by the present inventor, overlay marks provided at the four corners or the periphery of the sample are used to correct the alignment accuracy at the time of drawing. Since the area is large, it is possible to correct for pattern rotation, distortion, positional accuracy, etc.
Small area such as beam deflection area (several mm square)
Since there is no means for compensating for the improvement of overlay accuracy for the target, overlay correction of the pattern drawn in the deflection area (field) of the beam is not performed at all, and the connection accuracy of the pattern in overlay drawing Also, there is a problem that the overlay accuracy is reduced.

Further, in the future, the beam deflection area tends to be expanded from the standpoint of placing importance on throughput (for example, about 6 mm square), and the necessity of overlay correction within the deflection area becomes important.

Therefore, an object of the present invention is to provide a technique for improving the connection accuracy and the overlay accuracy of patterns in overlay drawing, thereby improving the yield of products.

Of the inventions disclosed in the present application, the outline of a typical one will be briefly described as follows.

[0008]

That is, a step of forming a first layer having a first pattern on a surface of a sample by a lithographic technique and an etching technique, and a step of forming the first layer on the layer based on the first layer. A pattern forming method comprising: forming a second layer having a second pattern by a lithography technique and an etching technique, wherein a maximum or arbitrary deflection amount of an electron beam is applied when a pattern writing operation of the first layer is performed. The alignment mark is drawn while being deflected by.

[0009]

According to the above-mentioned means, the alignment mark for field connection is drawn by deflecting the beam during (or before or after drawing) the first layer, and the beam when the first layer is patterned. By setting the conditions of the deflection distortion shape and the conditions of the beam deflection distortion shape when the second layer is drawn to be the same or similar, the pattern of the first layer due to factors such as measurement error at the time of correction and environmental conditions Misalignment with the pattern of the second layer can be eliminated. Therefore, it is possible to improve the overlay accuracy of the patterns, and it is possible to improve the yield reduction of the products due to the misalignment of the patterns.

[0010]

1 is a sectional view showing an embodiment of an electron beam drawing apparatus according to the present invention.

The housing 1 of the electron beam drawing apparatus of the present embodiment has a cylindrical upper part, and a box-shaped sample chamber (which is evacuated during processing) is formed in the lower part thereof. Inside the cylindrical portion of the housing, the electron gun 2, the first shaping diaphragm 3, the first shaping lens 4, the shaping deflector 5, the second shaping lens 6, the second shaping aperture 7, the reduction lens 8, and the blanking are provided. Each of the electrode 9, the electromagnetic deflector 10, the electrostatic deflector 11, and the focusing lens 12 is sequentially arranged from the upper side to the lower side.

A sample 14 is arranged in the processing chamber 13, and the sample 14 is irradiated with an electron beam 15. Further, a registration mark 16 is drawn on the sample 14.
A system control computer 17 is provided to control the entire system, and the system control computer 17 includes an electromagnetic deflector 10, an electrostatic deflector 11, and a focusing lens 12.
Deflection Control System 18 for Deflection Control of Deflection System
Are connected.

Further, a signal processing system 19 is provided for processing the signal detected by the alignment mark 16, and the processed output is sent to the system control computer 17.

FIG. 2 is a schematic perspective view showing the structure of the stage portion for moving the sample 14 and its periphery. Sample 14
Is set on the stage 21, and an X drive motor 20a and a Y drive motor 20b are attached to move the stage 21 in the X and Y directions.

In the case of drawing with the above configuration, the sample 14 is placed on an X drive table and a Y drive table (not shown) provided in the processing chamber 13. After the inside of the processing chamber 13 is evacuated, electrons are emitted from the electron gun 2, and the molding means including the first molding diaphragm 3 and the second molding diaphragm 7, the reduction lens 8, the electromagnetic deflector 10, and the electrostatic deflector 11 are used. The electron beam is narrowed down on the sample through the deflecting means, the focusing lens 12 and the like, and the electron beam can be moved to a width of several mm by operating the deflecting means.

A first layer having a first pattern is formed on the surface of a semiconductor wafer (or a transparent glass substrate, a wiring substrate, etc.) as a sample 14 by a lithographic technique and an etching technique, and the first layer is used as a reference. When the second layer having the second pattern is formed on the layer by the lithography technique and the etching technique, the electron beam 15 is corrected after the deflection distortion of the electron beam 15 which is performed when the pattern of the first layer is drawn. The alignment mark 16 is drawn on the first layer with 15 being deflected. In this drawing, the conditions required by the present invention are listed below.

(1) The amount by which the electron beam 15 is deflected can be set to a maximum value or an arbitrary value.

(2) In order to set the drawing area of the alignment mark 16 to the minimum or desired position, the stage 21 is moved by using the X drive motor 20a and the Y drive motor 20b so that the alignment mark 16 is located at the designated position. Can be drawn.

(3) Since the deflection distortion amount distorted during the drawing of the pattern of the first layer is recognized, the alignment marks can be arbitrarily specified and the interval (time) during the drawing of the pattern of the first layer. 16 drawings can be drawn.

Next, the procedure of alignment drawing on the sample 14 on which the alignment mark 16 and the pattern of the first layer are formed will be described.

First, the alignment mark 16 on the sample 14 is detected (measured) using the electron beam 15. In this case, the detecting means may be a method of deflecting the electron beam 15, or the X drive motor 20a and Y directly below the electron beam 15.
There is a method of moving and detecting the stage 21 using the drive motor 20b. A signal obtained by detecting the alignment mark 16 with the electron beam 15 is applied to the signal processing system 19 and processed. The processing result is input to the system control computer 17, and the correction value is calculated on the system control computer 17. The correction value calculated by the system control computer 17 is fed back to the deflection control system 18, and the electron beam 15 is overlapped and drawn in a state of deflection distortion similar to that when the pattern of the first layer is formed.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above-mentioned embodiment, the alignment mark 16 has a cross shape, but a "B" shape,
It may be a "#" shape or the like.

Further, in the above-mentioned embodiment, the drawing apparatus using the electron beam has been described, but instead of the electron beam, a laser, X
It goes without saying that the present invention can be applied to a drawing device using lines and the like. It can also be applied to a stepper.

Further, although a mask (reticle) is shown as a sample in the above-mentioned embodiment, a semiconductor wafer, a wiring substrate, etc. can also be applied.

Further, in the above-mentioned embodiment, since the example in which the phase shift technique is used is shown, two layers are formed on the sample 14. However, when the phase shift technique is not used, three layers or more are formed. You can also do it.

Besides, in the above embodiment, the beam is deflected to draw the alignment mark when the first layer is drawn. However, the beam is deflected in advance to form the drawn mark on the underlying substrate. You can leave it. If you do this,
It is possible to improve the connection accuracy between the masks.

[0028]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, a step of forming a first layer having a first pattern on the surface of a sample by a lithographic technique and an etching technique, and a step of forming a first layer on the layer based on the first layer by a lithographic technique and an etching technique. A method of forming a pattern, comprising forming a second layer having a second pattern, the method comprising: aligning an electron beam with a maximum or an arbitrary deflection amount during a pattern writing operation of the first layer. Since the marks are drawn, it is possible to improve the overlay accuracy and the drawing accuracy of the patterns, and as a result, it is possible to improve the yield reduction of the products due to the misalignment of the patterns.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an electron beam drawing apparatus according to the present invention.

FIG. 2 is a schematic perspective view showing a configuration of a stage unit and its periphery for moving the sample shown in FIG.

[Explanation of symbols]

 1 Housing 2 Electron Gun 3 First Forming Aperture 4 First Forming Lens 5 Forming Deflector 6 Second Forming Lens 7 Second Forming Aperture 8 Reduction Lens 9 Blanking Electrode 10 Electromagnetic Deflector 11 Electrostatic Deflector 12 Focusing Lens 13 Processing chamber 14 Sample 15 Electron beam 16 Alignment mark 17 System control computer 18 Deflection control system 19 Signal processing system 20 Deflection control system 20a X drive motor 20b Y drive motor 21 Stage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroya Ota 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (2)

[Claims] 1. A step of forming a first layer having a first pattern on a surface of a sample by a lithography technique and an etching technique, and a step of forming a first layer on the layer with the lithography technique and the etching technique based on the first layer. A method of forming a pattern, comprising forming a second layer having a second pattern, the method comprising: aligning an electron beam with a maximum or an arbitrary deflection amount during a pattern writing operation of the first layer. A pattern forming method in electron beam drawing, which comprises drawing a mark. 2. A pattern forming apparatus for controlling a deflection of an electron beam to form a predetermined pattern on a surface of a sample, comprising:
Drawing means for drawing the alignment mark in the state where the electron beam is deflected at the maximum or an arbitrary deflection amount at the time of pattern drawing work of the layer, and the pattern drawing of the second layer is started by the operation of deflecting the alignment mark by the means. Detected before,
A pattern forming apparatus in electron beam writing, comprising: a control unit that feeds back the detection result to the deflection distortion correction amount.