Substrate and manufacturing method thereof

1. A glass core substrate, comprising: a first glass layer; a second glass layer, disposed on the first glass layer; a third glass layer, disposed on the second glass layer; a first bonding layer, disposed between the first glass layer and the second glass layer; a second bonding layer, disposed between the second glass layer and the third glass layer; and a conductive connector, passing through the first glass layer, the first bonding layer, the second glass layer, the second bonding layer, and the third glass layer, wherein the conductive connector is configured to provide a vertical conductive path penetrating through the first glass layer, the first bonding layer, the second glass layer, the second bonding layer, and the third glass layer; the glass core substrate further comprising: a first redistribution circuit layer, a second redistribution circuit layer disposed on surfaces of the first glass layer and the third glass layer respectively, and a surface treatment layer disposed on the first redistribution circuit layer, wherein an outer layer of the first redistribution circuit layer has a first pitch, an outer layer of the second redistribution circuit layer has a second pitch, and, the first pitch is smaller than the second pitch.

2. The glass core substrate according to claim 1 , wherein a coefficient of thermal expansion of the first glass layer is equal to a coefficient of thermal expansion of the third glass layer and a coefficient of thermal expansion of the second glass layer is greater than a coefficient of thermal expansion of the first glass layer.

3. The glass core substrate according to claim 1 , a thickness of the first glass layer equal to a thickness of the third glass layer.

4. The glass core substrate according to claim 1 , wherein tapered shape of vias in the first redistribution circuit layer and tapered shape of vias in the second redistribution circuit layer are opposite.

5. The glass core substrate according to claim 1 , wherein a size of vias in the first redistribution circuit layer is gradually increases away from the first glass layer, and a size of vias in the second redistribution circuit layer is gradually increases in a direction away from the third glass layer.

6. The glass core substrate according to claim 1 , wherein the first glass layer, the second glass layer and the third glass layer have the same pitch, and larger than the first pitch of the first redistribution circuit layer, and smaller than the second pitch of the second redistribution circuit layer.

7. A manufacturing method of a glass core substrate, comprising: providing a first glass layer, a second glass layer, and a third glass layer; performing bonding process to bond the first glass layer and the second glass layer through a first bonding layer and bond the second glass layer and the third glass layer through a second bonding layer; and removing portions of the first glass layer, the second glass layer, the third glass layer, the first bonding layer, and the second bonding layer to form an opening; forming conductive connectors penetrated through the first glass layer, the second glass layer, the third glass layer; and forming a first redistribution circuit layer and a second redistribution circuit layer on the first glass layer and the third glass layer respectively, wherein a pitch of the first redistribution circuit layer is smaller than a pitch of the second redistribution circuit layer, and the first redistribution circuit layer is configured to connect to the chips.

8. The manufacturing method of the glass core substrate according to claim 7 , wherein three etching process steps are performed to remove portions of the first glass layer, the second glass layer, the third glass layer, the first bonding layer, and the second bonding layer.

9. The manufacturing method of the glass core substrate according to claim 8 , wherein the first glass layer and the third glass layer are removed at first, then, the first bonding layer, the second bonding layer are removed, and the second glass layer is removed at last.

10. The manufacturing method of the glass core substrate according to claim 9 , wherein after the bonding process, a laser modification process is performed on the first glass layer, and the third glass layer.

11. The manufacturing method of the glass core substrate according to claim 7 , wherein forming conductive connectors further comprising: a conductive material is conformally formed on the surfaces of the glass layer and extends into the opening to form the conductive connectors.

12. The manufacturing method of the glass core substrate according to claim 7 , wherein forming conductive connectors further comprising: the conductive material fills up the opening, wherein the conductive connector is provided a vertical conductive path of the substrate and the conductive connector is through glass via.

13. The manufacturing method of the glass core substrate according to claim 7 , wherein after the etching process, a planarization process is performed.

14. The manufacturing method of the glass core substrate according to claim 7 , wherein forming the first redistribution circuit layer and a second redistribution circuit layer further comprises: forming a first film on the third glass layer; forming the first redistribution circuit layer on the first layer with the first film; removing the first film; and forming a second redistribution circuit layer on the third layer to configure an unsymmetric substrate; and forming a surface treatment layer disposed on the first redistribution circuit layer.

15. The manufacturing method of the glass core substrate according to claim 14 , wherein a material of the first film comprises organic film material, and a material of the second film comprises organic film material.