Reverse optical mastering for data storage disks
View Patent ↗A data storage master disk and method of making a data storage master disk. The data storage disk master is for use in a data storage disk replication process. The data storage disk molding processes produces replica disks having a surface relief pattern with replica lands and replica grooves. The method includes providing a master substrate. The master substrate is at least partially covered with a layer of photosensitive material. A surface relief pattern having master lands and master grooves is recorded in the data storage disk master, including the steps of exposing and developing the photosensitive material. The exposing and developing of a specified thickness of photosensitive material is controlled to form master grooves extending down to a substrate interface between the master substrate and the layer of photosensitive material, such that the width of the master grooves at the substrate interface corresponds to a desired width of the replica lands.
1. A master disk comprising:
a master substrate; and
a layer of photosensitive material covering at least a portion of the master substrate, the photosensitive material including a master pattern defined by adjacent master lands and master grooves, wherein the master grooves extend down to the master substrate, wherein the master grooves define master groove bottoms and the master lands define master land tops, and wherein a track pitch of the master pattern is less than 425 nanometers and a width of the groove bottoms is greater than 25 percent of the track pitch.
2. The master disk of claim 1 , wherein the master groove bottoms are flat and coplanar and wherein the master groove bottoms include sharp corners.
3. The master disk of claim 1 , wherein the master grooves define a groove depth which is approximately equal to a thickness of the layer of photosensitive material and the master grooves extend down to the master substrate.
4. The master disk of claim 1 , wherein the master grooves define a groove depth between 20 and 120 nanometers.
5. The master disk of claim 1 , wherein the width of the groove bottoms is greater than 35 percent of the track pitch.
6. The master disk of claim 5 , wherein the width of the groove bottoms is greater than 50 percent of the track pitch.
7. A master disk comprising:
a master substrate; and
a layer of photosensitive material covering at least a portion of the master substrate, the photosensitive material including a master pattern that is inverse of a desired replica pattern, the master pattern defining a track pitch less than 2 multiplied by a laser spot size associated with a laser used to perform laser etching of the master pattern in the photosensitive material, wherein the master pattern is defined by adjacent master lands and master grooves and wherein the master lands correspond to grooves of the desired replica pattern and the master grooves correspond to lands of the desired replica pattern, wherein the master grooves extend down to the master substrate such that master groove bottoms are flat and coplanar so that land tops of the desired replica pattern are flat and coplanar.
8. The master disk of claim 7 , wherein a track pitch of the master pattern is less than 700 nanometers.
9. The master disk of claim 7 , wherein a track pitch of the master pattern is less than 425 nanometers and a width of the master groove bottoms is greater than 25 percent of the track pitch.
10. The master disk of claim 9 , wherein the width of the groove bottoms are greater than 35 percent of the track pitch.
11. The master disk of claim 7 , wherein the master groove bottoms are flat and coplanar and wherein the master groove bottoms include sharp corners.
12. The master disk of claim 7 , wherein the track pitch is less than 1.6 multiplied by the laser spot size.
13. The master disk of claim 7 , wherein the master pattern further includes one of pits, bumps and ridges.
14. The master disk of claim 7 , wherein the master groove bottoms define widths between 80 and 200 nanometers.
15. A master disk comprising:
a master substrate; and
a layer of photosensitive material covering at least a portion of the master substrate, the photosensitive material including a master pattern that is inverse of a desired replica pattern, the master pattern defining a track pitch less than 2 multiplied by a laser spot size associated with a laser used to perform laser etching of the master pattern in the photosensitive material, wherein the track pitch is less than 700 nanometers.
16. The master disk of claim 15 , wherein the master pattern defines master lands and master grooves wherein a track pitch of the master pattern is less than 425 nanometers and a width of bottoms of the master grooves is greater than 25 percent of the track pitch.
17. The master disk of claim 16 , wherein the width of the bottoms of the master grooves is greater than 35 percent of the track pitch.
18. The master disk of claim 15 , wherein the master pattern defines master lands and master grooves and wherein the master grooves define bottoms that are flat and coplanar and wherein the master groove bottoms include sharp corners.
19. The master disk of claim 15 , wherein the track pitch is less than 1.6 multiplied by the laser spot size.
20. The master disk of claim 15 , wherein a depth of the master grooves is less than an initial thickness of the photosensitive material prior to the laser etching.