Grinding method of a disk-shaped substrate and grinding apparatus

1. A grinding method of a disk-shaped substrate that grinds a disk-shaped substrate including a portion having a hole at the center thereof while rotating the disk-shaped substrate, comprising:

grinding an inner circumference of the disk-shaped substrate while an inner circumference grinding device is fed in a radial direction toward an outer circumference of the disk-shaped substrate and grinding the outer circumference of the disk-shaped substrate while an outer circumference grinding device is fed in the radial direction toward the inner circumference of the disk-shaped substrate; and

stopping the feedings of the inner circumference grinding device and the outer circumference grinding device at the same time.

2. The grinding method of a disk-shaped substrate according to claim 1 , further comprising removing a portion remaining on the inner circumference and the outer circumference of the disk-shaped substrate by continuing rotation of the disk-shaped substrate for a determined time in the state of stopping the feedings.

3. The grinding method of a disk-shaped substrate according to claim 1 , wherein the disk-shaped substrate is held by a holding device that presses and holds upper and lower surfaces of the disk-shaped substrate.

4. The grinding method of a disk-shaped substrate according to claim 1 , wherein the inner circumference grinding device and the outer circumference grinding device have rotatable grinding surfaces.

5. The grinding method of a disk-shaped substrate according to claim 1 , wherein each of the inner circumference grinding device and the outer circumference grinding device has a rough grinding portion and a finishing grinding portion.

6. The grinding method of a disk-shaped substrate according to claim 5 , wherein the feedings of the inner circumference grinding device and the outer circumference grinding device in the radial direction are stopped at the same time in grinding by the rough grinding portions; and

the inner circumference grinding device and the outer circumference grinding device are rotated for a predetermined time in a state where the positions of the inner circumference grinding device and the outer circumference grinding device are maintained.

7. The grinding method of a disk-shaped substrate according to claim 5 , wherein the inner circumference grinding device and the outer circumference grinding device are grinding stones, each of the grinding stones continuously forming the rough grinding portion and the finishing grinding portion in an axial direction thereof; and

after grinding by each of the rough grinding portions, grinding by each of the finishing grinding portions is performed by moving the inner circumference grinding device and the outer circumference grinding device in the axial direction so that each of the finishing grinding portions is opposed to the disk-shaped substrate.

8. The grinding method of a disk-shaped substrate according to claim 7 , wherein the feedings of the inner circumference grinding device and the outer circumference grinding device in the radial direction are stopped at the same time during grinding by the finishing grinding portion; and

the inner circumference grinding device and the outer circumference grinding device are rotated for a predetermined time in a state where the positions of the inner circumference grinding device and the outer circumference grinding device are maintained.