Method of detecting photoresist scum, method of forming semiconductor package and photoresist scum detection apparatus

1. A method of detecting a photoresist scum, comprising:

forming a photoresist layer with opening patterns on a carrier;

performing a plasma etching process to the photoresist scum in the opening patterns of the photoresist layer;

injecting first charges to the opening patterns of the photoresist layer;

after injecting the first charges, measuring and calculating a first surface potential difference of at least one of the opening patterns;

determining whether the first surface potential difference of the at least one of the opening patterns is equal to or greater than a first predetermined value,

wherein the method further comprises performing a descum process to the opening patterns of the photoresist layer when the first surface potential difference is less than the first predetermined value;

forming conductive patterns in the opening patterns of the photoresist layer:

removing the photoresist layer;

injecting second charges to the photoresist scum aside the conductive patterns; and

after injecting the second charges, detecting whether the photoresist scum is present aside at least one of the conductive patterns.

2. The method of claim 1 , wherein the detecting comprises:

measuring a first surface potential and a second surface potential aside the at least one of the conductive patterns at two different time points; and

calculating a second surface potential difference between the first surface potential and the second surface potential.

3. The method of claim 2 , further comprising determining whether the second surface potential difference is equal to or greater than a second predetermined value.

4. The method of claim 3 , further comprising heating the substrate to remove the second charges when the second surface potential difference is equal to or greater than the second predetermined value.

5. The method of claim 3 , further comprising performing a descum process to the conductive patterns when the second surface potential difference is less than the second predetermined value.

6. The method of claim 1 , wherein the second charges comprise H + or (H 2 O) n H + .

7. The method of claim 1 , wherein the second charges comprise CO 3 −2 .

8. A method of detecting a photoresist scum, comprising:

forming a photoresist layer with opening patterns on a carrier;

performing a plasma etching process to the photoresist scum in the opening patterns of the photoresist layer;

injecting charges to the opening patterns of the photoresist layer;

after injecting the charges, measuring and calculating a surface potential difference of at least one of the opening patterns; and

determining whether the surface potential difference of the at least one of the opening patterns is equal to or greater than a predetermined value,

wherein the method further comprises performing a descum process to the opening patterns of the photoresist layer when the surface potential difference is less than the predetermined value.

9. The method of claim 8 , further comprising heating the carrier to remove the charges when the surface potential difference is equal to or greater than the predetermined value.

10. The method of claim 8 , further comprising forming conductive patterns in the opening patterns.

11. A method of detecting a photoresist scum, comprising:

forming a photoresist layer with opening patterns on a carrier;

performing a plasma etching process to the photoresist scum in the opening patterns of the photoresist layer;

injecting positive charges to the opening patterns of the photoresist layer;

after injecting the positive charges, measuring and calculating a surface potential difference of at least one of the opening patterns; and

determining whether the surface potential difference of the at least one of the opening patterns is equal to or greater than a predetermined value,

wherein the method further comprises performing a descum process to the opening patterns of the photoresist layer when the surface potential difference is less than the predetermined value.

12. The method of claim 11 , further comprising heating the carrier to remove the positive charges when the surface potential difference is equal to the predetermined value.

13. The method of claim 11 , wherein the positive charges comprise H + .

14. The method of claim 11 , wherein the positive charges comprise (H 2 O) n H + .

15. The method of claim 11 , further comprising heating the carrier to remove the positive charges when the surface potential difference is greater than the predetermined value.

16. The method of claim 11 , further comprising forming conductive patterns in the opening patterns of the photoresist layer.

17. The method of claim 16 , further comprising removing the photoresist layer.

18. The method of claim 17 , further comprising detecting whether the photoresist scum is present aside the conductive patterns.

19. The method of claim 11 , wherein the carrier further has a die and an encapsulation layer thereon, the encapsulation layer is around the die, and the photoresist layer is disposed on the die and the encapsulation layer.

20. The method of claim 19 , wherein the die comprises an application-specific integrated circuit (ASIC) chip, an analog chip, a sensor chip, a wireless radio frequency chip, a voltage regulator chip or a memory chip.