Bonded body, wafer support member using the same, and wafer treatment method
A bonded body consisting of a ceramic member and a metal composite member of which bonding layer is less likely to be eroded by plasma is provided. The bonded body comprises the ceramic member that has two opposing main surfaces with a first metal layer provided on one of the main surfaces, the metal composite member that has two opposing main surfaces with a second metal layer provided on one of the main surfaces, and a brazing material layer that joins the first metal layer and the second metal layer, wherein the brazing material layer has an outer circumferential surface that has a depression formed therein at middle position in the direction of thickness thereof, with the depression having width at least one third the thickness of the brazing material layer.
1. A bonded body comprising:
a ceramic member having main surfaces opposed each other and a first metal layer formed on one of the main surfaces;
a metal composite member having main surfaces opposed each other and a second metal layer formed on one of the main surfaces;
a brazing material layer to bond the ceramic member and the metal composite member,
wherein the brazing material layer has a depression in the middle of a circumference surface of the brazing material layer and wherein a width of the depression is not less than ⅓ of a thickness of the brazing material layer,
wherein an inner surface of the depression is curved surface.
2. The bonded body according to claim 1 ; wherein a depth of the depression is not less than 0.1 times the thickness of the brazing material layer nor more than 10 times the thickness of the brazing material layer.
3. The bonded body according to claim 1 ; wherein the depression is formed by hollowing the outer circumferential surface of the brazing material layer toward the inside as a whole.
4. The bonded body according to claim 1 ; wherein the circumference surface is located away inward from a periphery of the first metal layer and an periphery of the second metal layer.
5. A wafer supporting member having the bonded body of claim 4 ;
wherein the other main surface of the two main surfaces of the ceramic member is face on which a wafer is mounted.
6. The wafer supporting member according to claim 5 ;
wherein the ceramic member has an electrostatic chucking electrode built-in.
7. The bonded body according to claim 1 ; wherein a distance between the periphery and the circumference surface is not less than 0.1 times the thickness of the brazing material layer nor more than 0.18 times a maximum diameter of the first metal layer and second metal layer.
8. The bonded body according to claim 1 ; wherein the brazing material layer is made by one material selected from a group consisting of an aluminum brazing material and an indium brazing material.
9. The bonded body according to claim 1 ; wherein a thickness of the brazing material layer is in a range from 0.01% of a maximum diameter of a binding face between the metal layer and the brazing material layer to 0.3% of the maximum diameter.
10. The bonded body according to claim 1 ; wherein a void ratio of the brazing material layer is in a range from 1% to 10%.
11. A wafer supporting member having the bonded body of claim 1 ;
wherein the other main surface of the two main surfaces of the ceramic member is face on which a wafer is mounted.
12. The wafer supporting member according to claim 11 ;
wherein the ceramic member has a heater built-in.
13. The wafer supporting member according to claim 12 ;
wherein the ceramic member has an electrostatic chucking electrode built-in.
14. The wafer supporting member according to claim 11 ;
wherein the ceramic member has an electrostatic chucking electrode built-in.