Process control for package formation

A package comprising:

• a first package component;
• a dielectric isolation region over and contacting the first package component, wherein the dielectric 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, and is in physical contact with, a corresponding one of the first plurality of layers;
• a second package component over and bonding to the first package component;
• and
• a dielectric layer over and bonding to top surfaces of both of the second package component and the dielectric isolation region.

A package comprising:

• a first package component, wherein the first package component comprises an electrical connector;
• a dielectric isolation region over and in physical contact with the first package component, wherein the dielectric isolation region comprises:
• a first dielectric layer;
• a second dielectric layer over the first dielectric layer;
• and
• a third dielectric layer over the second dielectric layer, wherein the first dielectric layer comprises a first dielectric material, the second dielectric layer comprises a second dielectric material different from the first dielectric material, and the third dielectric layer comprises a third dielectric material different from the second dielectric material;
• and
• a conductive feature penetrating through the dielectric isolation region to electrically connect to the electrical connector of the first package component;
• and
• a second package component over and joined to the first package component, wherein the dielectric isolation region comprises a first sidewall contacting the second package component.