Method for manufacturing master substrate used for manufacturing grooved molding substrate, method for manufacturing stamper for manufacturing grooved molding substrate, method for manufacturing grooved molding substrate, grooved molding substrate, memory medium, memory device, and computer

Abstract

A substrate having a photoresist coated thereon is exposed to exposure light along a line through a lens 1 . The exposure position is moved from the initial position O 1 to a position O 2 that is separated from the initial position by a distance corresponding to the sum of a groove width Gw and a land width Lw. The exposure is carried out along a line parallel to the initial exposure line. By repeating this, exposed areas having a width Lw and a separation Gw are formed on the photoresist. The photoresist is developed to remove the exposed areas of the photoresist. A resin or the like is pressed on it to form a replica. From the replica, a stamper is manufactured using an electroforming method. Finally, a grooved molding substrate is manufactured from a glass or resin using the stamper. Although the land width Lw is defined by the effective spot diameter φ of the optical system, the groove width Gw can be less than this value.

What is claimed is:  
     
         1 . A method for manufacturing a master substrate for producing a grooved molding substrate, comprising: 
 a preparing step that prepares a substrate on which a photoresist is coated;    an exposing step that exposes the photoresist to light with a predetermined pattern such that the exposed part corresponds to a land of the grooved molding substrate to be produced; and    a developing step that obtains the master substrate by developing the photoresist.    
     
     
         2 . A method for manufacturing a master substrate for producing a grooved molding substrate, comprising: 
 a preparing step that prepares a substrate on which a photoresist is coated;    an exposing step that exposes the photoresist to light with a predetermined pattern such that the exposed part corresponds to a land of the grooved molding substrate to be produced;    a developing step that forms a resist pattern by developing the photoresist, the resist pattern exposing a part of the substrate;    an etching step that etches the part of the substrate exposed in the developing step; and    a removing step that obtains the master substrate by removing the photoresist.    
     
     
         3 . A method for manufacturing a master substrate for use in producing a grooved molding substrate, comprising: 
 a first step that prepares a substrate on which a photoresist is coated;    a second step that exposes the photoresist with exposing light, the resultant photoresist having a portion that is exposed to the exposing light and a portion that is not exposed to the exposing light, the exposed portion corresponding to a land of the grooved molding substrate to be produced, the unexposed portion corresponding to a groove of the grooved molding substrate to be produced; and    a third step that obtains the master substrate by developing the photoresist exposed in the second step.    
     
     
         4 . The method according to    claim 3   , wherein the second step includes the steps of: 
 forming a part corresponding to a first land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along a first line with the exposing light;    moving an illuminating position from the first line to a second line that is separated from the first line by a distance corresponding to the sum of a groove width Gw and a land width Lw of the grooved molding substrate to be produced; and    forming a part corresponding to a second land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along the second line with the exposing light.    
     
     
         5 . The method according to    claim 4   , wherein the groove width Gw is about 0.1 μm or less.  
     
     
         6 . The method according to    claim 4   , wherein the groove width Gw is about 0.06 μm or less.  
     
     
         7 . The method according to    claim 4   , wherein the groove of the grooved molding substrate is at least one of a pit, a hollow, and discontinuity.  
     
     
         8 . The method according to    claim 4   , wherein the step of moving an illuminating position from the first line to a second line and the step of forming a part corresponding to a second land of the grooved molding substrate to be produced are repeated in that order a plurality of times by successively regarding the second line in the previous execution of the two steps as the first line in the repetition.  
     
     
         9 . The method according to    claim 3   , wherein the second step includes a step that forms a part corresponding to a spiral-shaped land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along a spiral line, the spiral line having an interval corresponding to the sum of a groove width Gw and a land width Lw of the grooved molding substrate to be produced.  
     
     
         10 . The method according to    claim 9   , wherein the groove width Gw is about 0.1 μm or less.  
     
     
         11 . The method according to    claim 9   , wherein the groove width Gw is about 0.06 μm or less.  
     
     
         12 . The method according to    claim 9   , wherein the groove of the grooved molding substrate is at least one of a pit, a hollow, and discontinuity.  
     
     
         13 . A method for manufacturing a master substrate for use in producing a grooved molding substrate, comprising: 
 a first step that prepares a substrate on which a photoresist is coated;    a second step that exposes the photoresist with exposing light, the resultant photoresist having a portion that is exposed to the exposing light and a portion that is not exposed to the exposing light, the exposed portion corresponding to a land of the grooved molding substrate to be produced, the unexposed portion corresponding to a groove of the grooved molding substrate to be produced;    a third step that obtains a resist pattern by developing the photoresist exposed in the second step;    a fourth step that etches a part of the substrate in accordance with the resist pattern; and    a fifth step that removes the photoresist from the substrate processed in the third step to obtain the master substrate for use in producing the grooved molding substrate.    
     
     
         14 . The method according to    claim 13   , wherein the second step includes the steps of: 
 forming a part corresponding to a first land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along a first line with the exposing light;    moving an illuminating position from the first line to a second line that is separated from the first line by a distance corresponding to the sum of a groove width Gw and a land width Lw of the grooved molding substrate to be produced; and    forming a part corresponding to a second land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along the second line with the exposing light.    
     
     
         15 . The method according to    claim 14   , wherein the groove width Gw is about 0.1 μm or less.  
     
     
         16 . The method according to    claim 14   , wherein the groove width Gw is about 0.06 μm or less.  
     
     
         17 . The method according to    claim 14   , wherein the groove of the grooved molding substrate is at least one of a pit, a hollow, and discontinuity.  
     
     
         18 . The method according to    claim 14   , wherein the step of moving an illuminating position from the first line to a second line and the step of forming a part corresponding to a second land of the grooved molding substrate to be produced are repeated in that order a plurality of times by successively regarding the second line in the previous execution of the two steps as the first line in the repetition.  
     
     
         19 . The method according to    claim 13   , wherein the second step includes a step that forms a part corresponding to a spiral-shaped land of the grooved molding substrate to be produced, by illuminating and exposing the photoresist along a spiral line, the spiral line having an interval corresponding to the sum of a groove width Gw and a land width Lw of the grooved molding substrate to be produced.  
     
     
         20 . The method according to    claim 19   , wherein the groove width Gw is about 0.1 μm or less.  
     
     
         21 . The method according to    claim 19   , wherein the groove width Gw is about 0.06 μm or less.  
     
     
         22 . The method according to    claim 19   , wherein the groove of the grooved molding substrate is at least one of a pit, a hollow, and discontinuity.  
     
     
         23 . A method for manufacturing a stamper for producing a grooved molding substrate, comprising the steps of: 
 obtaining a master substrate manufactured using the method according to any one of claims  1 - 4 ,  9 ,  13 - 14 , and  19  using a positive type photoresist as the photoresist;    forming a replica from the master substrate, the replica having a surface profile that is reverse of the surface profile of the master substrate; and    producing the stamper from the replica using an electroforming method.    
     
     
         24 . The method for manufacturing a stamper for producing a grooved molding substrate according to    claim 23   , wherein the replica is made of at least one of a metal and a resin.  
     
     
         25 . A method for manufacturing a stamper for producing a grooved molding substrate, comprising the steps of: 
 obtaining a master substrate manufactured using the method according to any one of claims  1 - 4 ,  9 ,  13 - 14 , and  19  using a negative type photoresist as the photoresist, and producing the stamper from the master substrate using an electroforming method.    
     
     
         26 . A method for manufacturing a stamper comprising steps of: 
 a preparing step that prepares a substrate on which a photoresist is coated;    an exposing step that exposes the photoresist to light with a predetermined pattern;    a developing step that forms a resist pattern by developing the photoresist;    an etching step that etches a part of the substrate not covered by the photoresist;    a removing step that obtains a master substrate by removing the photoresist;    a replica forming step that forms a resin replica from the master substrate; and    a stamper producing step that produces the stamper from the replica using an electroforming method.    
     
     
         27 . A method for manufacturing a grooved molding substrate comprising the steps of: 
 obtaining a stamper manufactured using the method of    claim 23   ; and    producing the grooved molding substrate by forming one of a glass and a resin with the stamper.    
     
     
         28 . A method for manufacturing a grooved molding substrate comprising the steps of: 
 obtaining a stamper manufactured using the method of    claim 25   , and    producing the grooved molding substrate by forming one of a glass and a resin with the stamper.    
     
     
         29 . A grooved molding substrate manufactured by an injection molding method using a stamper, wherein the groove width Gw is about 0.1 μm or less.  
     
     
         30 . The grooved molding substrate according to    claim 29   , wherein the groove width Gw is about 0.06 μm or less.  
     
     
         31 . The grooved molding substrate according to    claim 29   , wherein the slope angle of the sidewall of the groove is about 85° or more.  
     
     
         32 . The grooved molding substrate according to    claim 29   , wherein the ratio of the groove depth d to the groove width Gw is about 0.1 or more.  
     
     
         33 . The grooved molding substrate according to    claim 29   , wherein the groove is at least one of a pit and a discontinuity.  
     
     
         34 . A memory medium a substrate of which is manufactured by the method for manufacturing a grooved molding substrate according to    claim 27   .  
     
     
         35 . A memory medium a substrate of which is manufactured by the method for manufacturing a grooved molding substrate according to    claim 28   .  
     
     
         36 . A memory medium a substrate of which is the grooved molding substrate of    claim 29   .  
     
     
         37 . A memory device having the memory medium according to    claim 34   .  
     
     
         38 . A memory device having the memory medium according to    claim 35   .  
     
     
         39 . A memory device having the memory medium according to    claim 36   .  
     
     
         40 . A computer having the memory device according to    claim 37   .  
     
     
         41 . A computer having the memory device according to    claim 38   .  
     
     
         42 . A computer having the memory device according to    claim 39   .