Light interference system and substrate processing apparatus

1. A light interference system, comprising:

a light source configured to generate a measurement light;

a fiber, configured to propagate therethrough the measurement light, including a single-mode fiber, a multimode fiber and a connector connecting the single-mode fiber and the multimode fiber, a tip end of the fiber being formed of the multimode fiber and an end surface of the tip end of the fiber being configured to emit the measurement light to a measurement target object and receive a reflection light from the measurement target object; and

a measurement device configured to measure physical property of the measurement target object based on the reflection light.

2. The light interference system of claim 1 ,

wherein the connector has a tapered core that connects a core of the multimode fiber and a core of the single-mode fiber.

3. The light interference system of claim 1 ,

wherein the fiber has a cover configured to protect the end surface of the tip end of the fiber, and

the cover is made of a material configured to transmit the measurement light and is disposed on the end surface of the tip end of the fiber.

4. The light interference system of claim 3 ,

wherein the cover and the end surface of the tip end of the fiber are bonded to each other by an adhesive configured to transmit the measurement light.

5. The light interference system of claim 3 ,

wherein the fiber has an antireflection member configured to suppress reflection of the measurement light caused by the cover, and

the antireflection member is disposed between the end surface of the tip end of the fiber and the cover.

6. The light interference system of claim 3 ,

wherein the end surface of the tip end of the fiber is inclined from a plane orthogonal to an axial direction of the multimode fiber.

7. The light interference system of claim 1 ,

wherein a distance between the end surface of the tip end of the fiber and the measurement target object is equal to or larger than 0.5 mm and equal to or smaller than 1.5 mm.

8. A substrate processing apparatus, comprising:

a light interference system; and

a chamber main body configured to be vacuum-evacuated and to accommodate therein a measurement target object,

wherein the light interference system includes:

a light source configured to generate a measurement light;

a fiber, configured to propagate therethrough the measurement light, including a single-mode fiber, a multimode fiber and a connector connecting the single-mode fiber and the multimode fiber, a tip end of the fiber being formed of the multimode fiber and an end surface of the tip end of the fiber being configured to emit the measurement light to the measurement target object and receive a reflection light from the measurement target object; and

a measurement device configured to measure physical property of the measurement target object based on the reflection light.

9. The substrate processing apparatus of claim 8 ,

wherein the chamber main body includes therein a placing table having a plate to which a high frequency power is applied; and an electrostatic chuck disposed on the plate and configured to attract the measurement target object, a measurement hole penetrating the plate and the electrostatic chuck being formed in the placing table,

wherein the fiber includes:

a cover made of a material configured to transmit the measurement light and bonded to the end surface of the tip end of the fiber by an adhesive configured to transmit the measurement light, the cover being configured to protect the tip end of the fiber; and

a cylindrical coating member made of a conductive material and extended along an axial direction of the fiber to coat the adhesive and the cover, and

wherein the fiber is inserted through the measurement hole such that the measurement target object placed on the placing table and the cover face each other, and

the coating member is inserted through the measurement hole along with the fiber.

10. The substrate processing apparatus of claim 9 ,

wherein the coating member is interposed between the fiber and an inner surface of the measurement hole formed in the electrostatic chuck.

11. The substrate processing apparatus of claim 9 ,

wherein the coating member includes a lid extended along a diametrical direction of the fiber on a surface of the cover facing the measurement target object to coat the adhesive and the cover.