KR20130013384A - Cell type overlay vernier and method thereof - Google Patents

Cell type overlay vernier and method thereof Download PDF

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Publication number
KR20130013384A
KR20130013384A KR1020110075004A KR20110075004A KR20130013384A KR 20130013384 A KR20130013384 A KR 20130013384A KR 1020110075004 A KR1020110075004 A KR 1020110075004A KR 20110075004 A KR20110075004 A KR 20110075004A KR 20130013384 A KR20130013384 A KR 20130013384A
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KR
South Korea
Prior art keywords
pattern
vernier
overlay
cell type
bar
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KR1020110075004A
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Korean (ko)
Inventor
이종수
Original Assignee
에스케이하이닉스 주식회사
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Priority to KR1020110075004A priority Critical patent/KR20130013384A/en
Publication of KR20130013384A publication Critical patent/KR20130013384A/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
    • G03F7/70605—Workpiece metrology
    • G03F7/70616—Monitoring the printed patterns
    • G03F7/70633—Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
    • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
    • H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
    • H01L21/0274—Photolithographic processes

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Abstract

PURPOSE: A cell type overlay vernier and a method for forming the same are provided to accurately measure the overlay between cells by using a mother vernier and a son vernier which have the same pattern as a cell region. CONSTITUTION: A mother vernier(210) has the same shape as a first pattern(220a) formed in a cell region. The mother vernier measures the overlay of the first pattern. The first pattern has a bar shape. A son vernier(220) has the same shape as a second pattern(220b) formed in the cell region. The son vernier measures the overlay of the second pattern.

Description

Cell Type Overlay Vernier and Formation Method {CELL TYPE OVERLAY VERNIER AND METHOD THEREOF}

The present invention relates to a cell type overlay vernier, and more particularly, has a mother vernier and a son vernier having the same shape as the pattern formed in the cell region, thereby accurately measuring the overlay between cells. To a cell type overlay vernier.

Recently, since semiconductor devices are required to operate at a high speed and have a large storage capacity, developments have been made to improve electrical characteristics that enable a large amount of data to be processed quickly.

 In particular, as the degree of integration increases, the design rule is reduced, so that the technology for implementing the pattern has been variously developed. For this purpose, the wavelength of the exposure source for implementing the pattern is gradually shortened.

However, the critical dimension (CD) of the pattern currently being developed is required to be 40 nm or less, and since it is very difficult to form a pattern satisfying such a condition, a pattern is formed using one exposure mask as in the past. It is almost impossible to do.

Therefore, we are developing technologies to realize the desired pattern by using two or three exposure masks, which was previously patterned with one exposure mask, and for this, double patterning technology (DPT) and spacer patterning technology (Spacer Patterning) Technology, SPT) and the like are used.

 As such, when using multiple exposure masks, the degree of alignment between the pattern formed by the previous process (first layer) and the pattern to be formed in the current process (second layer) is very important. Frame items such as align keys, overlay vernier, etc., need to be correctly formed.

In other words, as the device technology becomes smaller, the overlay control becomes increasingly important in the photolithography process as the overlap margin becomes smaller.

1 illustrates an overlay vernier in the form of a conventional box in box.

Referring to FIG. 1, the conventional box-in-box overlay vernier 100 includes a mother box 110 having a box shape on the outside and an sonza 120 having a box shape on the inside.

In the conventional box-in-box overlay vernier 100, the distance between the mother 110 and the son 120 is measured to determine the pattern already formed on the wafer in the previous process (first layer) and the current process (second layer). The degree of overlay between the patterns to be formed was measured.

However, the conventional box-in-box overlay vernier 100 has the following problems.

First, the size of the cell is several tens of nanometers (nm), the mother 110 and son 120 formed in the conventional overlay vernier 100 has a size of several tens of micrometers (um) much larger than the size of the cell. This causes a difference in the environment between the cell area and the scribe area in which the overlay vernier is formed, which causes a collapse of the line pattern used as the overlay vernier, which inhibits the overlay signal when measuring the overlay and thus the overlay accuracy. There was a problem that (overlay accuracy) decreased.

Second, since the shapes of the mother 110 and son 120 formed in the overlay vernier 100 do not have the same shape as the pattern formed with a dense density in the cell area, the cells are formed when the overlay vernier is formed. There was a problem in that a loading effect due to a difference in etching speed with a region is generated, thereby degrading the characteristics of the overlay vernier.

The technical problem to be solved by the present invention is a cell having a mother vernier and son vernier having the same shape as the pattern formed in the cell area capable of accurately measuring the overlay between the cells of a small size It is to provide a type overlay vernier and its forming method.

The cell type overlay vernier according to the present invention for achieving the technical problem is formed in the same shape as the first pattern formed in the cell region of the first layer (mother) for measuring the overlay (overlay) of the first pattern (mother vernier); And a son vernier for measuring an overlay of the second pattern formed in the same shape as the second pattern to be formed in the cell region of the second layer.

In addition, the method for forming a cell type overlay vernier according to the present invention for achieving the above technical problem, (a) the same shape as the first pattern formed in the cell region of the first layer by performing a first exposure (1st exposure) process Forming a mother vernier with; And (b) performing a second exposure process to form a son vernier having the same shape as the second pattern to be formed in the cell region of the second layer.

According to the present invention, there is no collapsing or loading effect of the pattern when forming the overlay vernier, and the technical effect of accurately measuring the overlay between cells in a CD process of 40 nm or less is accurately achieved. have.

1 illustrates an overlay vernier in the form of a conventional box in box.
Figure 2 shows a first embodiment of an overlay vernier of cell type form of the invention.
3 shows a second embodiment of an overlay vernier of cell type form of the invention.
4 shows a third embodiment of an overlay vernier of the cell type of the invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 2 shows a first embodiment of an overlay vernier of cell type form of the invention.

Referring to FIG. 2, as a first embodiment of the present invention, an overlay vernier 200 having a cell type has a first exposure for forming a mother vernier 210 having a line pattern. ) And a second exposure process for forming a son vernier 220 of a bar pattern.

The first exposure process scribes a wafer by exposing light using a dipole illumination system to a line pattern 210 formed parallel to each other at a predetermined interval on the first reticle. Create a mother vernier in the region.

The shape of the line pattern 210 has a horizontal long bar pattern which is the same when the long bar pattern is formed in the cell region of the first layer in the horizontal direction. .

In this case, the width of the line pattern 210 is preferably formed from 40 nm to 80 nm, which is 1 to 2 times the size of the cell, and the interval between the plurality of line patterns to be formed in the vertical direction is the second exposure. In consideration of the size of the son vernier pattern to be formed in the (2nd exposure) process, a sufficient free space is provided so that the patterns do not overlap each other.

The second exposure process is performed after the first exposure process and is an annular illumination system for the first bar pattern 220a and the second bar pattern 220b formed on the second reticle. The light is exposed using to generate a son vernier in the scribe area of the wafer.

The first bar pattern 220a and the second bar pattern 220b are the same as the short bar in the horizontal direction when the short bar pattern is formed in the horizontal direction in the cell area of the second layer. ) Has the form of a pattern.

In this case, the first bar pattern 220a and the second bar pattern 220b are separated from each other in a horizontal direction at regular intervals rather than connected to each other, which is a line formed in the first exposure process. line) to distinguish it easily from patterns.

In this case, the width of the first bar pattern 220a and the second bar pattern 220b is preferably 40 nm to 80 nm, which is 1 to 2 times the size of the cell, and the first bar pattern 220a and the second bar pattern ( 220b) is formed in plurality in the vertical direction with a sufficient clearance so as not to overlap with the mother vernier pattern formed in the first exposure process.

Thus, the cell type overlay vernier 200 according to the present invention has a mother vernier 210 and a cell region having the same shape as the long bar-shaped pattern formed in the cell region in the scribe region of the wafer. It includes a son vernier 220 having the same shape as the short bar-shaped pattern formed.

3 shows a second embodiment of an overlay vernier of cell type form of the invention.

Referring to FIG. 3, as a second embodiment of the present invention, an overlay vernier of a cell type has a first exposure process for forming a mother vernier 310 of a line pattern. And a second exposure process for forming a son vernier 320 of a hole pattern.

The first exposure process is a scribe of a wafer by exposing light using a dipole illumination system on a line pattern 310 formed parallel to each other at a predetermined interval on the first reticle. Create a mother vernier in the region.

The line pattern 310 has a horizontal long bar pattern which is the same as the long bar pattern formed in the cell area of the first layer in the horizontal direction.

In this case, the width of the line pattern 310 is preferably formed from 40 nm to 80 nm, which is 1 to 2 times the size of the cell, and the interval between the plurality of line patterns to be formed in the vertical direction is the second exposure. In order to avoid overlapping with the son vernier pattern to be formed in the 2nd exposure process, sufficient space is provided.

The second exposure process is performed after the first exposure process, and is annular to the hole pattern 320 having the same size formed parallel to each other at a predetermined interval on the second reticle. An illumination system is used to expose the light to create a son vernier in the scribe area of the wafer.

In this case, the hole pattern 320 has a circle having the same shape as a contact hole pattern when a contact hole pattern is formed in a horizontal direction in a cell area of the second layer. It is preferable to form 40 nm-80 nm in diameter.

In addition, a plurality of hole patterns 320 are formed in a vertical direction with a sufficient free space so as not to overlap with a mother vernier pattern formed in a first exposure process.

As a result, the cell type overlay vernier 300 of the present invention has a mother vernier 310 and a cell region having the same shape as a long bar-shaped pattern formed in the cell region in the scribe region of the wafer. It includes a son vernier (320) having the same shape as the contact hole pattern formed.

4 shows a third embodiment of an overlay vernier of the cell type of the invention.

Referring to FIG. 4, as a third embodiment of the present invention, an overlay vernier 400 having a cell type may be formed to form a mother vernier 410 having a line pattern formed in an oblique direction. It is formed by performing a first exposure process and a second exposure process for forming a son vernier 420 having a bar pattern formed in an oblique direction.

The first exposure process exposes light using a dipole illumination system to a line pattern 410 formed on the first reticle, thereby causing a mother vernier in the scribe area of the wafer. Create

The shape of the line pattern 410 is a long bar in the diagonal direction which is the same shape when the long bar pattern is formed in the diagonal direction inclined at a predetermined angle in the cell area of the first layer. bar) has a pattern.

At this time, the width of the line pattern 410 is preferably formed from 40nm to 80nm, which is 1 to 2 times the size of the cell, the interval between the plurality of line patterns to be formed in a diagonal direction is the second In consideration of the size of the son vernier pattern to be formed in the 2nd exposure process, sufficient space is provided so that the patterns do not overlap.

The second exposure process is performed after the first exposure process, and is an annular illumination system for the first bar pattern 420a and the second bar pattern 420b formed on the second reticle. The light is exposed using to create a son vernier in the scribe area of the wafer.

When the first bar pattern 220a and the second bar pattern 220b have a plurality of short bar patterns separated from each other in a diagonal direction inclined at a predetermined angle in the cell region of the second layer. It has the same short bar pattern in the diagonal direction.

In this case, the first bar pattern 420a and the second bar pattern 420b are not connected to each other but have a separated shape at regular intervals, which is a line pattern formed in the first exposure process. Easy to distinguish from.

In this case, the widths of the first bar pattern 420a and the second bar pattern 420b are preferably 40 nm to 80 nm, which is 1 to 2 times the size of the cell, and the first bar pattern 420a and the second bar pattern ( 420b may be formed in plural in a diagonal direction with sufficient free space so as not to overlap with a mother vernier pattern formed in the first exposure process.

As a result, the cell type overlay vernier 400 of the present invention is formed in a mother vernier and a cell region having the same shape as a diagonal long bar pattern formed in the cell region in the scribe region of the wafer. It includes a son vernier that has the same shape as the diagonal short bar pattern.

Meanwhile, in the first, second, and third embodiments, the first and second exposure processes are exposed using a dipole and an annular illumination system, respectively, but are not limited thereto. Naturally, various illumination system conditions can be used.

Hereinafter, a method for measuring overlay between layers will be briefly described using a cell type overlay vernier implemented in the first, second, and third embodiments.

The overlay measurement method between layers using the cell type overlay vernier of the present invention is a mother vernier pattern and a son by using a conventional scanning electron microscope (CD-SEM). It can be implemented by measuring the line width (CD) of the vernier pattern.

Hereinafter, the principle of measuring the line width (CD) of the pattern using the CD-SEM will be briefly described.

The primary electrons emitted from the electron gun of the CD-SEM are accelerated by applying to the anode at an acceleration voltage of 800 ~ 1000V, and then connected with a magnetic lens to enter the wafer surface. The size of line width (CD) is measured by detecting emitted secondary electrons and processing them.

In this case, the CD-SEM has a resolution of about 10 nm or less, and the degree of secondary electron emission is determined according to the type of wafer surface material, acceleration voltage, and beam current amount.

In addition, the overlay measurement method between layers using the cell type overlay vernier of the present invention is a conventional image base overlay (diffraction overlay) equipment, TEM, i-cans Overlays can be measured using the equipment, and various overlay measuring equipment can be used without being limited thereto.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the invention.

210: mother vernier pattern
220: son vernier pattern
220a: first bar pattern
220b: second bar pattern

Claims (6)

A mother vernier formed in the same shape as the first pattern formed in the cell region of the first layer to measure an overlay of the first pattern; And
The cell type overlay vernier is formed in the same shape as the second pattern to be formed in the cell region of the second layer, and has a son vernier for measuring the overlay of the second pattern. . The cell type overlay vernier of claim 1, wherein the first pattern has a bar shape having a long bar shape in a horizontal direction. The method of claim 1,
The second pattern is a cell type overlay vernier, characterized in that the bar pattern having a short bar shape in the horizontal direction separated from each other at regular intervals, or a hole pattern having a circular shape . The cell type overlay vernier of claim 1, wherein the first pattern and the second pattern are formed in parallel to each other in an inclined shape at a predetermined angle. The cell type overlay vernier of claim 4, wherein the first pattern has a shape of a line pattern having a long bar shape. 5. The method of claim 4,
The second pattern is a cell type overlay vernier, characterized in that the bar pattern having a bar-shaped pattern is separated from each other at regular intervals.
KR1020110075004A 2011-07-28 2011-07-28 Cell type overlay vernier and method thereof KR20130013384A (en)

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KR1020110075004A KR20130013384A (en) 2011-07-28 2011-07-28 Cell type overlay vernier and method thereof

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Application Number Priority Date Filing Date Title
KR1020110075004A KR20130013384A (en) 2011-07-28 2011-07-28 Cell type overlay vernier and method thereof

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KR20130013384A true KR20130013384A (en) 2013-02-06

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