JP2007140128A - Substrate selecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a selecting device that can efficiently select a blank suitable for quality specifications of an aimed photomask. <P>SOLUTION: The substrate selecting device is equipped with: a light shielding film defect information database 125 for accumulating information about light shielding film defects of a mask blank; a light shielding film defect registering unit 120; a drawing information database 190 for accumulating drawing information about a pattern to be drawn; a drawing information registering unit 180; a design information database 220 for accumulating design information including important information and non-important information of the pattern brought in from LSI layout design data 200; a design information registering unit 180; and a selecting unit 130 for selecting a mask blank suitable for an aimed product by one or more means from the light shielding film defect information, the drawing information and the design information accumulated in the respective databases, so as to select a mask blank by the selecting unit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for selecting a substrate for a photomask used for manufacturing an LSI, and more particularly to a light-shielding film-forming substrate (also called mask blanks) for manufacturing a photomask in which a light-shielding film is formed on one main surface of a transparent substrate. The light shielding film deposition substrate suitable for the target photomask is selected from the defect information of the light shielding film, the mask design information, and the drawing information, and the light shielding film of the selected light shielding film deposition substrate is selected. The present invention relates to a substrate selection apparatus that applies a photosensitive material on top thereof and supplies the image for drawing for producing a photomask.

In order to realize high integration and ultra-miniaturization of LSIs that progress from a half-pitch 65 nm node to a 45 nm node, in photolithography, as a high-resolution technique in an exposure apparatus, the lens has a high NA and immersion exposure. Technology, exposure technology with modified illumination, etc. are rapidly being developed.
On the other hand, measures for improving the resolution of a photomask (also referred to as a reticle) used for photolithography include miniaturization and high accuracy of a conventional binary mask composed of a light transmitting portion and a light shielding portion, and light interference. A phase shift mask such as a Levenson type phase shift mask that improves resolution by using a halftone phase shift mask composed of a light transmitting part and a semi-transmitting part has been put into practical use. The phase shift mask requires two to three plate makings in the mask manufacturing process, and the manufacturing / inspection time increases.

In addition, when the mask pattern is transferred onto the wafer with the miniaturization of the LSI, the deformation of the mask pattern at the time of wafer transfer is corrected in advance in order to improve the deformation of the pattern shape due to the optical proximity effect. Optical proximity correction (OPC: Optical Proximity Correction) is used. OPC is shifting from rule-based OPC (weak OPC) processing, which is corrected by graphic calculation processing based on a rule table based on an exposure transfer experiment, to model-based OPC (strong OPC) processing, which is corrected based on an optical simulation. Jog for applying serifs and biases in the pattern corners is complicated, and a fine auxiliary pattern that is not resolved on the wafer, called a non-resolution assist pattern (SRAF), is also actively used. Yes.
As described above, practical use of phase shift masks, OPCs, etc. increases the mask data scale, leading to increased pattern data processing time, pattern drawing time, and inspection processing time, increasing the difficulty of mask manufacturing and manufacturing. Costs are also rising.

  Conventionally, a photomask is manufactured by a process as shown in FIG. First, a substrate (mask blank) in which a light-shielding film or shifter film 920 made of a metal thin film such as chromium is formed on a transparent substrate 910 such as quartz by a sputtering method or the like is prepared (FIG. 9A). Then, after applying a photosensitive material layer (photosensitive resin film, photosensitive resist or simply resist) 930 on the blanks light-shielding film or shifter film 920, heat drying treatment is performed to remove the solvent remaining in the film. In addition, the adhesiveness with the metal thin film is improved (FIG. 9B). Next, ionizing radiation 940 such as EB (Electron Beam) or laser light is selectively irradiated to the photosensitive material layer 930 of the substrate on which the photosensitive material layer is applied, and is drawn and exposed in a desired pattern shape. (FIG. 9 (c)). Next, after developing the photosensitive material layer 930 to form a resist pattern 935 (FIG. 9D), the light shielding film 920 made of a metal thin film exposed from the opening of the resist pattern 935 is etched to form a light shielding film pattern. 925 is formed (FIG. 9E). Finally, the resist pattern 935 is removed to obtain a photomask in which the light shielding film pattern 925 is formed on one main surface of the transparent substrate (FIG. 9F). Thereafter, inspection and correction as necessary were performed to obtain a desired photomask.

  Needless to say, the quality of the photomask produced in the production of the photomask is greatly influenced by the quality of the photosensitive material layer coated substrate used for pattern drawing. There are many types of material layer coated substrates, which are complicated to manage, and in the inspection of the manufacturing process, good products and defective products are discriminated based on certain standards, and only good products are used. It is a fact. However, there are various quality specifications for the target photomask products, and there are various differences in the quality and sensitivity of the photosensitive material layer even on the photosensitive material layer coated substrate that has become non-defective in the inspection. It could not be said that the substrate that matched the quality specification of the photomask product was selected, and the selection of the substrate to be used had a great influence on inspection and correction. In particular, in the production of a photomask with a half pitch of 65 nm or higher, even a minute defect of about 100 nm on the substrate may become a fatal defect. In order to reduce the defect, first, a high-quality mask is used. We had to select the appropriate board.

In recent years, by the present applicant, from the group of photosensitive material layer coated substrates after photosensitive material coating, a photosensitive material layer coated substrate suitable for the target product is obtained from light shielding film defect information, photosensitive material defect information, and drawing pattern information. There has been proposed a substrate selection apparatus for selecting and providing for drawing for photomask fabrication (see Patent Document 1).
However, when the substrate selection apparatus described in Patent Document 1 is used, a large number of substrates are prepared in the state of the photosensitive material coated substrate, not in the state of the light shielding film forming substrate, and an appropriate substrate is selected from these substrates. However, at the practical level, there are many substrates that are not used even if a photosensitive material is applied, and expensive photosensitive materials are wasted, which is a problem in terms of cost and productivity. It was.

For this reason, the applicant has further proposed a substrate selection device and a substrate supply method for selecting a substrate in the state of a light-shielding film-formed substrate (see Patent Document 2).
However, even when the substrate selection apparatus described in Patent Document 2 is used, the number of light-shielding film-formed substrates that are inappropriate due to the miniaturization of defects such as pinholes to be subjected to defect inspection increases, and the material cost increases. This has led to an increase in mask costs and has become a problem. Further, Patent Document 2 describes a design rule as an electron beam drawing address unit, but merely shows an address unit as mask pattern drawing information. What is the use of LSI layout design information? Was also not disclosed.
JP 2002-55437 A JP 2002-278046 A

As described above, LSIs are becoming denser and finer every year, and even in the photomasks used for the fabrication, there is a need for further high-precision and high-quality pattern formation. Therefore, there is a need for a substrate selection apparatus that can efficiently select a substrate that conforms to the quality specifications, and that can sufficiently cope with cost and productivity, excluding substrates with defects such as pinholes. It was.
The present invention has been made in view of the above problems. In other words, it is a substrate selection device used for pattern drawing for manufacturing photomasks, except for unsuitable substrates that cause pinhole defects or foreign object defects, etc., and a substrate that is suitable for the quality specifications of the target photomask product. It is an object of the present invention to provide a substrate selection apparatus that can be selected well and that can sufficiently cope with cost and productivity without wasting a light-shielding film-formed substrate and a photosensitive material-coated substrate.

  In order to solve the above problems, in the present invention, in conventional photomask manufacturing, LSI information is already missing in photomask specifications and mask drawing data, and details of LSI layout design information are given. The present invention has been completed by paying attention to the fact that it has not been used and is not utilized. That is, there are various types of LSI layout patterns, but the importance of these patterns varies depending on the purpose and use of the pattern, and quality assurance such as defect tolerance is not the same depending on the pattern. . The prior art cannot cope with the difference in quality assurance based on the difference in the LSI layout pattern, and determines whether the substrate defect is good or not uniformly. Accordingly, the present invention provides a substrate selection device that understands the intention of an LSI designer, effectively utilizes design information, and manufactures a mask while avoiding pinhole defects on the substrate.

  In order to solve the above-described problem, a substrate selection apparatus according to the invention of claim 1 includes a light shielding film forming substrate group for producing a photomask in which a light shielding film is formed on one main surface of a transparent substrate. A substrate selection device that selects a light-shielding film-forming substrate suitable for the target photomask, applies a photosensitive material on the light-shielding film of the selected light-shielding film-forming substrate, and provides it for drawing for photomask production A light shielding film defect information database for accumulating light shielding film defect information of the light shielding film deposition substrate group, a light shielding film defect registration unit for registering light shielding film defect information in the light shielding film defect information database, and drawing A drawing information database for storing drawing information of a pattern to be drawn, a drawing information registration unit for registering drawing information of a pattern to be drawn in the drawing information database, and important information on a pattern from LSI layout design data A design information database for storing design information incorporating non-important information; a design information registration unit for registering design information in the design information database; and shading film defect information and drawing information stored in the databases. A light-shielding film formation substrate selection unit that selects a light-shielding film formation substrate suitable for the target photomask by one or more means from the design information. The light-shielding film deposition substrate suitable for the photomask to be selected is selected.

  According to a second aspect of the present invention, there is provided the substrate selecting apparatus according to the first aspect, wherein the important information of the pattern taken into the design information is an MPU pattern, a RAM pattern, a ROM pattern, or a clock pattern. Any one or more types of pattern information, and the non-critical information of the pattern includes a CMP dummy pattern, a non-resolution assist pattern, a library cell dummy pattern, an auxiliary pattern for avoiding crosstalk between power sources, and a guard for preventing electrostatic breakdown The pattern information is one or more of a ring pattern, a VDD-VSS power supply gate capacitance pattern, a power supply line pattern, and a ground pattern.

  According to a third aspect of the present invention, there is provided the substrate selection apparatus according to the first or second aspect, wherein the design information is stored in the design information database as area information or mark information. It is what.

  According to a fourth aspect of the present invention, there is provided the substrate selecting apparatus according to any one of the first to third aspects, wherein a predetermined photosensitive material is formed on the light shielding film of the selected light shielding film deposition substrate. Photosensitive material defect inspection is performed on the photosensitive material coated substrate manufactured by coating the photosensitive material defect information database for storing the obtained photosensitive material defect information, and the photosensitive material defect information is stored in the photosensitive material defect information database. A photosensitive material defect registration unit for registration, photosensitive material defect information accumulated in the photosensitive material defect information database, drawing information accumulated in the drawing information database, design information accumulated in the design information database, And a photosensitive material coated substrate determination unit that determines a photosensitive material coated substrate suitable for the target photomask by one or more means, and the photosensitive material coated substrate determination unit determines the target photomask. It is characterized in selecting a compatible photosensitive material coating the substrate.

  The substrate selection apparatus according to a fifth aspect of the present invention is the substrate selection apparatus according to any one of the first to fourth aspects, wherein the light shielding film deposition substrate selection unit is a light shielding film obtained from light shielding film defect information. Considering the film defect rank, the drawing rank obtained from the drawing information, and the design rank obtained from the design information, the substrate rank selection unit for selecting the light shielding film deposition substrate, and considering the light shielding film defect position and the drawing pattern edge. One or more of a pattern edge selection unit for selecting a substrate and an all pattern selection unit for selecting a substrate in consideration of a light shielding film defect position and all drawing patterns are provided.

  The substrate selection apparatus according to a sixth aspect of the present invention is the substrate selection apparatus according to any one of the first to fifth aspects, wherein the photosensitive material coated substrate determination unit is a photosensitive material obtained from photosensitive material defect information. Substrate rank determination unit that determines the photosensitive material coated substrate in consideration of the defect rank, the drawing rank obtained from the drawing information, and the design rank obtained from the design information, the substrate in consideration of the photosensitive material defect position and the drawing pattern edge One or more of a pattern edge determination unit that determines the substrate and an all pattern determination unit that determines the substrate in consideration of the photosensitive material defect position and the entire drawing pattern are provided.

  According to the substrate selection apparatus of the present invention, it is possible to efficiently select a light-shielding film-formed substrate or a photosensitive material-coated substrate that conforms to the quality specifications of the target photomask product. In particular, by using design information for substrate selection, it is possible to effectively use light-shielding film-deposited substrates and photosensitive material-coated substrates that have been determined to be defective in the past without wasting production. Thus, a substrate selecting apparatus capable of sufficiently improving the photomask mask accuracy and quality and cost can be obtained. According to the substrate selection apparatus of the present invention, it is possible to cope with high quality and low cost, particularly in a mask substrate used for photolithography with a half pitch of 65 nm node or later.

Hereinafter, an embodiment of a substrate selection device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an example of an embodiment of a substrate selection apparatus of the present invention and a flow of substrate supply processing. FIG. 2 is a diagram showing an example of pinhole defect inspection result data. FIG. 3 is a diagram showing an example of photosensitive material lot check result data. FIG. 4 is a diagram showing an example of the quality standard of the substrate. FIG. 5 is a diagram illustrating an example of a substrate selection input method. FIG. 6 is a flowchart showing an example of a light-shielding film formation substrate selection procedure by the rank determination unit of the substrate selection unit. FIG. 7 is a diagram showing an example of selecting the optimum substrate position by rotating the mask data every 90 ° and ranking the importance levels for each area based on the design information. FIG. 8 is an explanatory diagram of the selection of the light shielding film deposition substrate by the edge selection unit of the substrate selection unit.

  An embodiment of the substrate selection apparatus of the present invention will be described with reference to FIG. In this example, a light-shielding film is formed on one main surface of a transparent substrate, and defect information of the light-shielding film is selected from a group of light-shielding film-forming substrates (blanks) for producing a photomask with no photosensitive material layer applied. This is a substrate selection device that selects a light-shielding film deposition substrate suitable for a target photomask product from drawing information and design information, and further applies a photosensitive material on the light-shielding film of the selected light-shielding film deposition substrate. , A substrate selection device for donation for drawing for photomask fabrication.

  As shown in FIG. 1, the substrate selection apparatus of this example includes a light shielding film defect information database 125 that accumulates light shielding film defect information of each light shielding film deposition substrate 110, and the light shielding film defect information in the light shielding film defect information database 125. A shading film defect registration unit 120 for registering a pattern, a drawing information database 190 for storing drawing information of a pattern to be drawn, and a drawing information registration unit for registering drawing information of a pattern to be drawn in the drawing information database 180, a design information database 220 for storing design information obtained by importing pattern important information and non-important information from the LSI layout design data 200, and a design information registration unit 210 for registering design information in the design information database 220. And one or more means from the shading film defect information, the drawing information, and the design information stored in each database. A light-shielding film formation substrate selection unit (also referred to as a substrate selection unit) 130 that selects a light-shielding film formation substrate 110 suitable for the target product, and further, the light-shielding film formation substrate selection unit 130 selects the light-shielding film A photosensitive material defect information database for performing a photosensitive material defect inspection on the photosensitive material coated substrate 115 produced by applying a predetermined photosensitive material to the film formation substrate 110 and accumulating the obtained photosensitive material defect information. 145, the photosensitive material defect registration unit 140 for registering photosensitive material defect information in the photosensitive material defect information database 145, the photosensitive material defect information stored in the photosensitive material defect information database 145, and the drawing information database 190. Design information database that stores drawing information and design information that incorporates important information and non-important information of patterns from LSI layout design data 200 20 and a design information registration unit 210 for registering design information in the design information database 220, a photosensitive material coated substrate determination for determining a photosensitive material coated substrate suitable for a target photomask product by one or more means. Part (also referred to as a board determination part) 150.

  First, each part of the substrate selection apparatus of this example and its processing, and the relationship between each part of the substrate selection apparatus and the flow of substrate supply processing will be briefly described with reference to FIG. In addition, it replaces with description of the embodiment of the board | substrate supply method of this invention with this.

First, a plurality of light shielding film deposition substrates (blanks) 110 (S11) in which a light shielding film or shifter film made of a metal thin film such as chromium is formed on a transparent substrate such as quartz by a vacuum film deposition method such as a sputtering method. On the other hand, a predetermined defect inspection is performed (S12), and the light shielding film defect registration unit 120 stores the result as light shielding film defect information in the light shielding film defect information database 125. As the defect inspection, the defect size and its defect coordinates (X, Y) can be obtained by a predetermined blank pinhole defect inspection machine as shown in FIG.
Next, the substrate selection unit 130 selects one from the light shielding film defect information accumulated in the light shielding film defect database 125, the drawing information accumulated in the drawing information database 190, and the design information accumulated in the design information database 220. The light shielding film deposition substrate applicable to the target product is selected by the above means (S13).

  The drawing information is registered in the drawing information database 190 based on the photomask specification 170, and includes drawing pattern information, arrangement information, drawing pattern ranking information, and the like. More specifically, the drawing machine, the substrate size, and the type of light shielding film Quality conditions such as substrate conditions such as pinhole defect inspection result rank, foreign object defect inspection result rank.

  The design information in the substrate selection apparatus of the present invention incorporates important information and non-important information of the design pattern in addition to the design rules, and is registered in the design information database based on the LSI layout design data 200. The LSI layout design pattern includes a pattern having important information such as an S-RAM pattern and a clock pattern and a pattern having non-important information such as a dummy pattern and a non-resolution assist pattern. For a defect such as a substrate, the tolerance of a pattern having important information is extremely strict, while the pattern having non-important information has a wide tolerance. Under the circumstances where the defect level becomes increasingly severe, judging these patterns based on the same standard and selecting substrate defects at the same level also requires excessive quality for the entire photomask, which means effective use of resources. Must not. Therefore, in this substrate selection apparatus, the design information taken into the design information database 220 is used for substrate selection.

More specifically, the important information captured in the design information of the substrate selection apparatus is one or more pattern information of MPU pattern, RAM pattern, ROM pattern, and clock pattern. It is difficult to correct a portion where the fine circuits are dense, and it is necessary to eliminate the existence of substrate defects as much as possible.
On the other hand, non-important information captured in the design information includes a CMP (Chemical Mechanical Polishing) dummy pattern, a non-resolution assist pattern (SRAF), a power crosstalk avoidance assist pattern, an electrostatic breakdown prevention guard ring pattern, and the like. There is one or more types of pattern information among non-circuit patterns, library cell dummy patterns, VDD-VSS power supply gate capacitance patterns, power supply line patterns, and ground patterns.

For example, the CMP dummy pattern is auxiliary pattern design information used in the semiconductor / LSI manufacturing process. However, even if the substrate is somewhat defective, it is not related to the circuit and is treated as non-critical information. As described above, in the present invention, process patterns and non-circuit patterns used when manufacturing semiconductors and LSIs that are not directly related to circuits are also included as design information.
In addition, the library cell dummy pattern is a pattern that is installed in advance in consideration of later circuit changes, but it is a cell that does not need to be used, so the tolerance for substrate defects is wide and unimportant. It can be information.
Furthermore, the VDD-VSS power supply gate capacitance pattern prevents a current from flowing between VDD and VSS when the power supply diode, decap, or logic for countermeasures against electrostatic breakdown is operated, and the power supply is swayed every time switching is performed. For this reason, the gate capacitance is included in the pattern, but it is not severe with respect to the substrate defect and can be regarded as non-critical information.

  In addition to the important information and the non-important information pattern information described above, there are, for example, a noise reduction diode (decap), a redundant circuit, etc. These pattern information includes important information and non-important information. It is located in between, and can be dealt with by separating it into important information or non-important information according to the design.

  As the substrate selection unit 130, a substrate rank selection unit 131 that selects a light shielding film deposition substrate in consideration of the rank obtained from the light shielding film defect information, the rank of the drawing pattern, and the design rank obtained from the design information, One or more of the pattern edge selection unit 132 for selecting the substrate in consideration of the position and the drawing pattern edge, and the all pattern selection unit 133 for selecting the substrate in consideration of the position of the light shielding film defect and the entire drawing pattern are selected as the substrate. What is provided as a means is mentioned. A more detailed description of substrate selection will be given later. In addition, the selection method of the light-shielding film forming substrate performed by the substrate rank selection unit 131, the pattern edge selection unit 132, and the all pattern selection unit 133 is here a substrate rank selection method, a pattern edge selection method, and an all pattern selection method. Call it.

  The input (corresponding to selection instruction input) when the substrate selection unit 130 selects a substrate suitable for the target product is displayed on an input screen (on the display unit of the computer terminal), for example, as shown in FIG. In response to substrate conditions such as drawing machine, substrate size, light shielding film type, quality conditions such as pinhole defect inspection result rank, and design rules, important information of design patterns, non-important information of patterns, The importance rank (in FIG. 5, the importance of the pattern is divided into three ranks as area information) is selected and used, and the light shielding film deposition substrate is selected by each selection section. High pattern importance rank means more severe against pinhole defects.

  Next, a target photosensitive material is applied and formed on the light shielding film (S14) on the light shielding film deposition substrate (S13) selected by the substrate selection unit 130 (S14), and the resulting photosensitive material coated substrate 115 (S15) is applied. On the other hand, the defect inspection of the photosensitive material is performed (S16), and the result is accumulated in the photosensitive material defect database 145 by the photosensitive material defect registration unit 140. The defect inspection of a photosensitive material is usually performed by inspecting a foreign matter defect with a predetermined inspection machine, and the defect size and the defect coordinates (X, Y) are expressed in a format such as a pinhole defect shown in FIG. Obtainable.

Next, from the photosensitive material defect information stored in the photosensitive material defect information database 145, the drawing information stored in the drawing information database 190, and the design information stored in the design information database by the substrate determination unit 150, 1 A photosensitive material coated substrate that can be applied to the target product is selected by one or more means (S17).
The substrate determination unit 150 considers the rank obtained from the photosensitive material defect information, the rank of the drawing pattern, and the rank obtained from the design information, and determines the photosensitive material coated substrate. One or more of a pattern edge determination unit 152 that determines a substrate in consideration of a drawing pattern edge and an all pattern determination unit 153 that determines a substrate in consideration of a photosensitive material defect position and an entire drawing pattern are provided as substrate selection means. The thing that is. These board determinations will also be described later.

  In addition, the determination method of the photosensitive material coated substrate performed by the substrate rank determination unit 151, the pattern edge determination unit 152, and the all pattern determination unit 153 is here a substrate rank determination method, a pattern edge determination method, and an all pattern determination method. Call. The input (corresponding to the determination instruction input) when determining the substrate suitable for the target photomask product by the substrate determination unit 150 is, for example, the pinhole defect inspection result rank shown in FIG. Can be displayed instead. On the input screen of the display unit of the computer terminal, the substrate conditions such as the drawing machine, the substrate size, the type of the light shielding film, and the quality conditions such as the design rule and the foreign substance defect inspection result rank, and the design conditions are selected and used, Each determination unit determines the photosensitive material coated substrate.

The photosensitive material coated substrate (S19) selected as OK by the substrate determination (S17) of the substrate determination unit 150 (S18) performs a lot check of the sensitivity of the photosensitive material (S20), and if there is no problem in sensitivity. Is provided for pattern drawing (S21).
Further, the substrate determination unit 150 determines that the substrate is not OK (S18). The substrate selection unit 130 selects a light-shielding film deposition substrate that can be applied to the target product again without using the photosensitive material coated substrate. (S13) Then, similarly to the above, the processing steps S14 to S17 are performed again, and the process is repeated until the substrate determination unit 150 determines that it is OK. Then, the photosensitive material-coated substrate determined to be OK (S19) is subjected to a lot check of the sensitivity of the photosensitive material (S20), as in the case of the above-mentioned substrate, and if there is no problem in sensitivity, it is provided to pattern drawing ( S21).

As a lot check of the sensitivity of the photosensitive material, for example, for each lot of photosensitive material, a sensitivity check is performed using a test piece (test substrate), and the result is stored as photosensitive material layer sensitivity lot check data. You may judge based on.
As photosensitive material sensitivity lot check data, for each substrate, for each photosensitive material application lot (in this case, the lot differs depending on the application date), the sensitivity is checked with a test piece, etc., and for each corresponding drawing machine. An appropriate exposure amount (irradiation amount) is determined, and for each substrate, the substrate size, light shielding film type, photosensitive material layer type, coating date, drawing machine, and exposure amount are associated with each other, for example, as shown in FIG. It is expressed as follows. In FIG. 3, + a is a correction of variation in sensitivity between lots of photosensitive material layers by increasing the exposure amount by + a.

(Substrate selection part)
Next, as an example of substrate selection by the substrate selection unit 130, the substrate rank selection unit 131, the pattern edge selection unit 132, and the all pattern selection unit 133 will be described in order.

(First example: board rank selection unit)
First, as a first example of substrate selection, FIG. 6 shows an example of a flow (algorithm) for selecting a light-shielding film-formed substrate having a rank suitable for the target photomask product by the substrate rank selection unit 131. This will be explained based on. In the example shown in FIG. 6, a substrate rank is designated from a photomask specification serving as a substrate selection criterion, and a corresponding ranked light shielding film deposition substrate is selected. Depending on the part, the substrate is selected as follows. The ranking of the light-shielding film deposition substrate is based on the light-shielding film defect information registered in the database for each of the target substrates, in the areas corresponding to the pattern areas (also referred to as drawing areas) of the photomask to be produced. The number of defects is extracted, and ranking is performed according to the number of extracted defects. First, a target substrate 521 corresponding to a use condition (photomask specification) 512 specified by a selection instruction input, such as a designated drawing machine, substrate size, and light shielding film type, is selected from the light shielding film deposition substrate group 511. The target substrate to be selected is selected (S510).

  Next, referring to the pinhole defect inspection result data 522, the pattern area 523 is defined as a predetermined one from the target substrate 521, as shown in FIG. The number of defects in the pattern area is ascertained in a state of being rotated every 90 ° (90 °, 180 °, 270 °) (S520). By rotating every 90 °, even within a predetermined pattern area, the number of defects occupied therein is different, and the optimum position of the substrate can be selected.

  At this time, as shown in FIG. 7B, based on the design information obtained by importing the important information and the unimportant information of the pattern from the LSI layout design data, the design rank that is ranked as area information or mark information for each pattern is obtained. It is used as the design standard 524 and applied to the substrate selection together with the pattern area (S520). FIG. 7B illustrates a case where the importance of design information incorporating important information and non-important information is divided into three ranks as area information.

As described above, an LSI layout pattern includes an important pattern such as an S-RAM. On the other hand, as a non-circuit pattern, a CMP dummy pattern, a non-resolution assist pattern (SRAF), and a crosstalk between power sources are avoided. There are non-critical patterns such as auxiliary patterns and guard rings. Some circuit patterns include important patterns such as clock line buffer gates, and other patterns such as noise reduction diodes (decaps), redundant circuits, and circuit change cells (EC cells) are slightly less important. The wiring pattern includes an important pattern such as a clock line, a non-important pattern such as a power supply line, and a ground pattern. As described above, the substrate information can be efficiently selected by determining the defect information of the pattern area by adding the design information incorporating the important information and the unimportant information of the pattern.
The important information and the non-important information of the pattern can be divided into two or more ranks as the importance rank of the pattern. For example, FIG. 5 shows a case of 3 ranks. However, since it becomes complicated when the number of ranks is too large, it is preferable to rank in the range of about 2 to 5 corresponding to the important information and non-important information of the pattern. Is more preferable.

  The target board 531 is compared with the quality standard (board rank) 532, the board board having a desired board rank is selected, and the ranking is performed with the priority ranking (S530), and the ranking-target board 541 with the priority ranking is given. Get. Thereby, a desired light-shielding film formation substrate is selected. In this way, the target substrates 541 of the target product are ranked and further prioritized, but the target substrate 541 meets the quality specification (quality standard) of the target photomask product. A desired substrate is selected (S540), and a photosensitive material is applied (corresponding to S14 in FIG. 1).

Note that the quality standards, which are the criteria for selecting a substrate determined from the photomask specification 170 shown in FIG. 1, correspond to the ranks based on design rules, pattern areas (X and Y sizes), pinhole defect inspection results, design information, and the like. For example, it is represented as shown in FIG.
FIG. 4 is an example of the quality standard of a substrate used for drawing by a raster type EB machine (electron beam drawing machine). The first row in the table is 0.1 μm address unit drawing, and the pattern area is 10,000 μm. This means that the pinhole defect inspection result rank is A and the foreign matter defect inspection result rank is B within the range of 10,000 μm.

(Second example: pattern edge selection unit)
Next, a second example will be described in which the substrate selection unit 130 selects a light-shielding film-formed substrate having a rank suitable for the target product in quality. FIG. 8 is an explanatory diagram of the second example, in which the substrate is selected in consideration of the light shielding film defect position and the drawing pattern edge. The pattern edge selecting unit 132 in the substrate selecting unit 130 performs the following operation. Select the board.

  In the second example, a substrate is selected from light-shielding film defect inspection information registered in the light-shielding film defect information database 125, drawing information registered in the drawing information database 190, and design information registered in the design information database 220. In the substrate selection unit 130, the probability P0 that a defect does not occur on the photomask on the target substrate based on the defect inspection information registered in the database in the defect probability calculation unit (not shown). Is what you want. Based on this probability P0, ranking is performed among the target substrates, and a substrate having a desired rank is selected. The selected light-shielding film deposition substrate is subjected to a photosensitive material coating process (corresponding to S14 in FIG. 1). When obtaining P0, the target substrate and the pattern area are rotated by 90 ° relative to the target substrate, the same calculation as in the case of 0 ° is performed, and P0 at each relative angle is obtained. Rank the item and select the one with the desired rank. By rotating every 90 °, the number of defects occupying the different pattern areas varies.

  At this time, as shown in FIG. 7B, based on the design information obtained from the LSI layout design data including the important information and the non-important information of the pattern, the design rank ranked as the area information for each pattern is used. By applying to the substrate selection in combination with the above-described rotation every 90 °, the optimum position of the substrate is selected, and the optimum substrate that matches the quality specification of the target photomask product is selected.

  In the P0 calculation method in the second example, if the defect is included in the pattern, the defect can be corrected later relatively easily. As a premise, the calculation method does not cause a defect, and only the pattern edge portion is related to the probability P0. Therefore, here, the substrate selection process of the second example is referred to as a pattern edge selection process, and a process for performing this process. This part is called a pattern edge selection part.

Hereinafter, an example of how to obtain the probability P0 that the defect does not occur on the photomask when the target substrate and the pattern area are in a predetermined relative positional relationship will be described with reference to FIG.
In order to make the explanation easy to understand, as a specific example, there are three defects (defects 811, 812, 813) in the drawing area (pattern area) 805 of the substrate area 801, and pattern data areas 831, 832, 833 are present. A method for obtaining the probability P0 that no defect occurs on the photomask when there are three will be described. First, for the defects 811, 812, and 813, the probabilities of straddling the periphery of the pattern in the pattern data area are calculated, and the probabilities P1, P2, and P3 of not straddling the periphery of the pattern in the pattern data area are calculated. And P0 = P1 × P2 × P3, and a probability P0 that no defect occurs on the photomask is obtained.

  The positional relationship between the target substrate and the pattern area, the pattern data area, and the pattern within the pattern data area is determined from the drawing pattern and the arrangement information. The probability P1 that the defect 811 does not straddle the periphery of the pattern in the pattern data area is obtained as a defect area 821 having a size larger than the defect in consideration of the error corresponding to the position of the defect 811 on the photomask to be manufactured. Then, a non-occurrence probability that is a probability that a defect does not occur in the peripheral portion of the pattern in the obtained defect area 821 is obtained.

  The pattern in the defect region 821 (size L × L), which is larger than the defect 811 into which the defect 811 enters, in consideration of the error in the case of FIG. As shown in the figure, the defective area 821 is a rectangular area in which the length of one side is L in the patterns 851 and 852. In this case, assuming that the defect has a circular shape of size dφ and the sum of the peripheral lengths of the patterns 851 and 852 is S1, the probability that the defect 811 straddles the periphery of the pattern in the pattern data area is approximately (S1 * D) / (L * L).

  Therefore, the probability P1 that the defect 811 does not straddle the peripheral portion of the pattern in the pattern data area can be approximately obtained as P1 = 1 − [(S1 × d) / (L × L)]. Similarly, probabilities P2 and P3 that the defects 812 and 813 do not straddle the peripheral portion of the pattern in the pattern data area are obtained. From the obtained P1, P2, and P3, a probability P0 that a defect does not occur on the photomask is obtained. In the case where there are three or more pattern data areas (corresponding to 831, 832, and 833), the calculation can be basically performed in the same manner.

(Third example: All pattern selection section)
Next, a third example will be briefly described in which the substrate selection unit 130 selects a light-shielding film-deposited substrate having a rank suitable for the target product in quality. In the third example, the substrate is selected in consideration of the light-shielding film defect position and the entire drawing pattern region. The substrate is selected by the all pattern selection unit (not shown) in the substrate selection unit 130 as follows. Make a selection. The third example also selects the substrate from the light shielding film defect inspection information, the drawing information, and the design information registered in each database. As in the second example, the substrate selection unit 130 includes a defect probability calculation unit. (Not shown), for each target substrate, a probability P01 that a defect does not occur on the photomask is obtained based on the defect inspection information registered in the database. In the case of the third example, only the pattern edge is not targeted as in the second example, and the probability that a defect occurs in the entire pattern area is selected. Ask for.

  For example, in the defect area 821 as shown in FIG. 8B, the probability that the circular defect 811 of size dφ straddles the pattern in the pattern data area is calculated as Sd / (L × L). However, Sd is the sum of the areas when the patterns 851 and 852 are thickened by d / 2 outward. Thus, the probability P11 that the defect 811 does not straddle the pattern in the pattern data area is obtained as P11 = 1− [Sd / (L × L)]. Similarly, the probabilities P12 and P13 in which the defects 812 and 813 do not straddle the pattern in the pattern data area can be obtained, and the photomask including the case where the defect is inside the pattern is obtained from P11, P21, and P31. The probability P01 that no defect occurs can be obtained.

When obtaining P01, similarly to the first and second examples, the target substrate and the pattern area are rotated by 90 ° relative to the target substrate, and the same calculation as in the case of 0 ° is performed. To determine P01 at each relative angle.
At this time, as shown in FIG. 7B, based on the design information obtained from the LSI layout design data including the important information and the non-important information of the pattern, the design rank ranked as the area information for each pattern is used. By applying to the selection of the substrate in combination with the rotation every 90 °, the optimum position of the substrate is selected, and the optimum substrate that meets the quality specification of the target photomask product is selected.

(Board judgment part)
Next, substrate determination by the substrate determination unit 150 will be described. As described above, as the substrate determination unit 150, the substrate rank determination unit 151 that determines the photosensitive material coated substrate in consideration of the rank obtained from the photosensitive material defect information, the rank of the drawing pattern, and the rank of the design information. , A pattern edge determination unit 152 that determines a substrate in consideration of a photosensitive material defect position, a drawing pattern edge, and design information, and an all pattern determination that determines a substrate in consideration of a photosensitive material defect position, all drawing patterns, and design information One having at least one of the units 153 as the substrate selection means is exemplified.

The substrate rank determination unit 151 calculates and ranks the number of defects for the photosensitive material coated substrate 115 in the same manner as the defect calculation of the processing of the substrate rank selection unit of the substrate selection unit 130, and from this and the photomask specification It is judged whether it can apply to drawing of the target product compared with the quality standard. In addition, the pattern edge determination unit 152 calculates the probability P0 for the photosensitive material coated substrate 115 in the same manner as the calculation of the processing probability of the pattern edge selection unit of the substrate selection unit 130. It is determined whether or not it can be applied to drawing. Further, the all pattern determination unit 153 calculates the probability P01 for the photosensitive material coated substrate 115 in the same manner as the calculation of the processing probability of the all pattern selection unit of the substrate selection unit 130. It is determined whether or not it can be applied to drawing.
The details of the substrate rank determination unit 151, the pattern edge determination unit 152, and the all pattern determination unit 153 are the same as the description of the substrate rank selection unit, the pattern edge selection unit, and the all pattern selection unit in the substrate selection unit, and will be omitted.

It is the schematic which shows the schematic structure which shows an example of embodiment of the board | substrate selection apparatus of this invention, and the flow of a board | substrate selection process. It is the figure which showed an example of the pinhole defect inspection result data. It is the figure which showed an example of the photosensitive material lot check result data. It is the figure which showed an example of the quality standard of a board | substrate. It is the figure which showed an example of the input method of board | substrate selection. It is the flowchart which showed an example of the light-shielding film film-forming board | substrate selection procedure by the rank determination part of a board | substrate selection part. It is explanatory drawing of selection of the optimal board | substrate position by rotation of layout design data, and rank classification | category of the importance for every area by design information. It is a figure for demonstrating selection of the light shielding film film-forming board | substrate by the edge selection part of a board | substrate selection part. It is a figure for demonstrating the manufacturing method of a photomask.

Explanation of symbols

110 light-shielding film deposition substrate 115 photosensitive material coating substrate 120 light-shielding film defect registration unit 125 light-shielding film defect information database 130 substrate selection unit (also referred to as light-shielding film deposition substrate selection unit)
131 substrate rank selection unit 132 pattern edge selection unit 133 all pattern selection unit 140 photosensitive material defect registration unit 145 photosensitive material defect information database 150 substrate determination unit (also referred to as photosensitive material application substrate determination unit)
151 Substrate rank determination unit 152 Pattern edge determination unit 153 All pattern determination unit 170 Photomask specification 180 Drawing information registration unit 190 Drawing information database 200 LSI layout design data 210 Design information registration unit 220 Design information database 511 Shielding film deposition substrate group 512 Usage conditions (photomask specifications)
521 Target substrate 522 Pinhole defect inspection data 523 Pattern area 524 Design standard 531 Target substrate 532 Quality standard 541 Rank target substrate 801 Substrate area 805 Pattern area (drawing area)
811, 812, 813 Defects 821, 822, 823 Defect areas 831, 832, 833 Pattern data areas 851, 852 Pattern (pattern)
910 Transparent substrate 920 Shading film (or shifter film)
925 Light-shielding film pattern 930 Photosensitive material layer 935 Resist pattern 940 Ionizing radiation

Claims (6)

Select a light-shielding film deposition substrate suitable for the target photomask from the group of light-shielding film deposition substrates for photomask fabrication in which a light-shielding film is deposited on one main surface of the transparent substrate, and select the light shielding A substrate selection device for applying a photosensitive material on a light-shielding film of a film-forming substrate and providing it for drawing for producing a photomask,
A light shielding film defect information database for accumulating light shielding film defect information of the light shielding film deposition substrate group; a light shielding film defect registration unit for registering light shielding film defect information in the light shielding film defect information database;
A drawing information database for storing drawing information of a pattern to be drawn; a drawing information registration unit for registering drawing information of a pattern to be drawn in the drawing information database;
A design information database for accumulating design information that incorporates pattern important information and non-important information from LSI layout design data; a design information registration unit for registering design information in the design information database;
A light-shielding film film-forming substrate selection unit that selects a light-shielding film film-forming substrate suitable for a target photomask by one or more means from light-shielding film defect information, drawing information, and design information stored in each of the databases; Have
A substrate selection apparatus, wherein the light shielding film deposition substrate selection unit selects a light shielding film deposition substrate suitable for a target photomask.   The important information of the pattern taken into the design information is at least one of MPU pattern, RAM pattern, ROM pattern, and clock pattern, and the non-important information of the pattern is a CMP dummy pattern, Non-resolving auxiliary pattern, library cell dummy pattern, auxiliary pattern for avoiding crosstalk between power supplies, guard ring pattern for preventing electrostatic breakdown, gate capacitance pattern between VDD and VSS, power supply line pattern, ground pattern The substrate selection apparatus according to claim 1, wherein the substrate selection apparatus is one or more types of pattern information.   The substrate selection apparatus according to claim 1, wherein the design information is stored in the design information database as area information or mark information. Photosensitive material defect inspection is performed on a photosensitive material coated substrate prepared by applying a predetermined photosensitive material on the light shielding film of the selected light shielding film deposition substrate, and the obtained photosensitive material defect information is accumulated. A material defect information database, and a photosensitive material defect registration unit for registering photosensitive material defect information in the photosensitive material defect information database,
From the photosensitive material defect information stored in the photosensitive material defect information database, the drawing information stored in the drawing information database, and the design information stored in the design information database, a target photomask is obtained by one or more means. A photosensitive material coated substrate determination unit for determining a suitable photosensitive material coated substrate;
4. The substrate selection apparatus according to claim 1, wherein the photosensitive material-coated substrate determination unit selects a photosensitive material-coated substrate that matches a target photomask. 5.   The light shielding film deposition substrate selection unit selects a light shielding film deposition substrate in consideration of the light shielding film defect rank obtained from the light shielding film defect information, the drawing rank obtained from the drawing information, and the design rank obtained from the design information. 1 of a substrate rank selection unit to select, a pattern edge selection unit to select a substrate in consideration of a light shielding film defect position and a drawing pattern edge, and an all pattern selection unit to select a substrate in consideration of a light shielding film defect position and all drawing patterns. The board | substrate selection apparatus of any one of Claims 1-4 provided with one or more. The photosensitive material coated substrate determination unit determines a photosensitive material coated substrate in consideration of a photosensitive material defect rank obtained from photosensitive material defect information, a drawing rank obtained from drawing information, and a design rank obtained from design information. One or more of a substrate rank determination unit, a pattern edge determination unit that determines the substrate in consideration of the photosensitive material defect position and the drawing pattern edge, and an all pattern determination unit that determines the substrate in consideration of the photosensitive material defect position and the entire drawing pattern 6. The substrate selection apparatus according to claim 1, further comprising:

Images