Process control for package formation
A method includes bonding a first and a second device die to a third device die, forming a plurality of gap-filling layers extending between the first and the second device dies, and performing a first etching process to etch a first dielectric layer in the plurality of gap-filling layers to form an opening. A first etch stop layer in the plurality of gap-filling layers is used to stop the first etching process. The opening is then extended through the first etch stop layer. A second etching process is performed to extend the opening through a second dielectric layer underlying the first etch stop layer. The second etching process stops on a second etch stop layer in the plurality of gap-filling layers. The method further includes extending the opening through the second etch stop layer, and filling the opening with a conductive material to form a through-via.
1. A package comprising:
a first device die;
a second device die and a third device die bonded to the first device die;
an isolation region between the second device die and the third device die, wherein the isolation region comprises:
a first etch stop layer having sidewall portions contacting the second and the third device dies and a bottom portion contacting a top surface of the first device die;
a first dielectric layer over the first etch stop layer;
a second etch stop layer over the first dielectric layer; and
a second dielectric layer over the second etch stop layer; and
a through-via penetrating through the isolation region to electrically connect to the first device die.
2. The package of claim 1 , wherein the through-via penetrates through all dielectric layers in the isolation region.
3. The package of claim 1 , wherein the through-via is tapered with upper portions increasingly wider than respective lower portions.
4. The package of claim 1 , wherein the first etch stop layer has a first thickness smaller than a second thickness of the second etch stop layer.
5. The package of claim 1 , wherein the first etch stop layer and the second etch stop layer are formed of a same material.
6. The package of claim 1 , wherein each of the first etch stop layer, the first dielectric layer, and the second etch stop layer is a conformal layer.
7. The package of claim 6 , wherein the second dielectric layer is a non-conformal layer.
8. The package of claim 1 , wherein the first dielectric layer is formed of a material different from materials of the first etch stop layer and the second etch stop layer.
9. The package of claim 8 , wherein the second etch stop layer is formed of an additional material different from materials of the first dielectric layer and the second dielectric layer.
10. A package comprising:
a first package component;
a second package component over the first package component; and
an isolation region encircling the second package component, wherein the isolation region comprises:
a first plurality of layers formed of a first material; and
a second plurality of layers formed of a second material different from the first material, wherein each of the second plurality of layers overlaps a corresponding one of the first plurality of layers.
11. The package of claim 10 , wherein the first plurality of layers comprise silicon nitride, and the second plurality of layers comprise silicon oxide.
12. The package of claim 10 , wherein the isolation region is over, and contacting, the first package component.
13. The package of claim 10 further comprising a through-via penetrating through the first plurality of layers and the second plurality of layers to electrically connect to the first package component.
14. The package of claim 10 , wherein the first package component comprises an interposer, and the second package component comprises a device die.
15. The package of claim 10 , wherein a bottom layer in the first plurality of layers comprises a horizontal portion in physical contact with a top surface of the first package component, and a vertical portion in physical contact with a sidewall of the second package component.
16. The package of claim 10 , wherein the first plurality of layers and the second plurality of layers are allocated alternatingly.
17. A package comprising:
a first package component, wherein the first package component comprises an electrical connector;
a second package component and a third package component over and bonding to the first package component;
an isolation region over the first package component, wherein the isolation region is between the second package component and the third package component, and wherein the isolation region comprises:
a first layer;
a second layer over the first layer; and
a third layer over the second layer, wherein the first layer and the third layer are formed of a same dielectric material; and
a conductive feature penetrating through the isolation region to electrically connect to the electrical connector of the first package component.
18. The package of claim 17 , wherein the isolation region further comprises a dielectric region filling rest of a gap between the second package component and the third package component, wherein the dielectric region is directly over a bottom portion of the third layer.
19. The package of claim 17 further comprising a redistribution line over the second package component and the third package component, wherein the redistribution line is electrically connected to the conductive feature.
20. The package of claim 17 , wherein the first layer is thinner than the third layer.