Peeling method and peeling apparatus

1. A peeling method comprising the steps of:

a first step of forming a separation layer over a substrate;

a second step of forming a layer to be separated over the separation layer;

a third step of forming a peeling starting point by separating a part of the layer to be separated from the separation layer;

a fourth step of peeling the layer to be separated from the substrate using the peeling starting point; and

a liquid supplying step of supplying liquid to the peeling starting point,

wherein the fourth step includes a step of heating a first portion of the substrate and a step of cooling a second portion of the layer to be separated,

wherein the first portion includes a portion that is not separated from the layer to be separated after the fourth step, and

wherein the second portion includes a portion separated from the substrate after the fourth step.

2. The peeling method according to claim 1 , wherein the liquid includes water.

3. The peeling method according to claim 1 , further comprising the step of a static electricity eliminating step of eliminating static electricity from a surface of the layer to be separated, the surface being exposed by separating from the substrate,

wherein the static electricity eliminating step is performed during at least one of a third period and a fourth period,

wherein the third period is in the fourth step, and

wherein the fourth period is after the fourth step.

4. The peeling method according to claim 1 , further comprising the step of a drying step of drying a surface of the layer to be separated, the surface being exposed by separating from the substrate,

wherein the drying step is performed after the fourth step.

5. The peeling method according to claim 1 , wherein the separation layer contains tungsten.

6. The peeling method according to claim 1 , further comprising the step of an oxidation step of oxidizing the separation layer,

wherein the oxidation step is performed between the first step and the second step.

7. The peeling method according to claim 6 , wherein the oxidation step includes a plasma treatment step performed under an atmosphere containing nitrous oxide (N 2 O).

8. A peeling method comprising the steps of:

a first step of forming a separation layer over a substrate;

a second step of forming a layer to be separated over the separation layer;

a third step of forming a peeling starting point by separating a part of the layer to be separated from the separation layer; and

a fourth step of peeling the layer to be separated from the substrate using the peeling starting point,

wherein in the fourth step, the layer to be separated is peeled from the substrate while at least a part of the layer to be separated is cooled and a part of the substrate is heated.

9. The peeling method according to claim 8 , further comprising the step of a liquid supplying step of supplying liquid between the layer to be separated and the separation layer,

wherein the liquid supplying step is performed during at least one of a first period and a second period,

wherein the first period is between the third step and the fourth step, and

wherein the second period is in the fourth step.

10. The peeling method according to claim 9 , wherein a temperature of the liquid is higher than 0° C. and lower than 100° C.

11. The peeling method according to claim 9 , wherein the liquid includes water.

12. The peeling method according to claim 1 , wherein a temperature of the liquid is higher than or equal to 60° C. and lower than or equal to 90° C.