Integrated fan-out structure with rugged interconnect

A method of forming a package assembly, comprising:

• forming a first dielectric layer over a carrier substrate;
• forming a first conductive line over the first dielectric layer;
• performing a first treatment process on the first conductive line with a first chemical, thereby roughening surfaces of the first conductive line;
• forming a second dielectric layer over and in direct contact with the first conductive line;
• forming a first portion of a conductive through-via through the second dielectric layer, wherein the first portion of the conductive through-via has a first set of opposing exterior sidewall surfaces that are embedded within the second dielectric layer, wherein the first portion of the conductive through-via is in direct contact with the roughened surfaces of the first conductive line and electrically coupled to the first conductive line, wherein the forming of the first portion comprises:
• forming a first opening through the second dielectric layer,
• depositing a metal layer in the first opening and over the second dielectric layer, and
• performing a planarization process to remove the metal layer over a top surface of the second dielectric layer;
• after forming the first portion of the conductive through-via, forming a second portion of the conductive through-via over the first portion, wherein the second portion includes a second set of opposing exterior sidewall surfaces above the second dielectric layer, wherein the forming of the second portion comprises:
• depositing a seed layer over the first portion of the conductive through-via,
• depositing a resist layer over the seed layer,
• forming a second opening through the resist layer,
• plating the second portion of the conductive through-via in the second opening,
• removing the resist layer, and
• etching the seed layer using the second portion of the conductive through-via as an etch mask;
• performing a second treatment process on the second portion of the conductive through-via with a second chemical, thereby roughening the second set of opposing exterior sidewall surfaces of the second portion of the conductive through-via while the first set of opposing exterior sidewall surfaces of the first portion of the conductive through-via are protected by the second dielectric layer physically contacting the first portion of the conductive through-via, the second treatment process being different than the first treatment process;
• after performing the second treatment process on the second portion of the conductive through-via with the second chemical, placing a device die over the second dielectric layer;
• and
• after placing the device die over the second dielectric layer, molding the device die and the conductive through-via in a molding material such that the molding material extends between the device die and the roughened second set of opposing exterior sidewall surfaces, the device die physically contacting the second dielectric layer, wherein the molding material is in direct contact with the roughened second set of opposing exterior sidewall surfaces.

A method of forming a package assembly, comprising:

• depositing a first dielectric layer over a carrier substrate;
• forming a conductive line over the first dielectric layer;
• depositing a second dielectric layer over the conductive line and in direct contact with the conductive line;
• forming a first portion of a conductive through-via through the second dielectric layer, wherein the first portion includes a first width and a first set of opposing sidewall surfaces that are embedded within the second dielectric layer, wherein the forming of the first portion comprises:
• forming an opening through the second dielectric layer,
• depositing a metal layer in the opening and over the second dielectric layer, and
• performing a planarization process to remove the metal layer over a top surface of the second dielectric layer;
• after forming the first portion of the conductive through-via, forming a second portion of the conductive through-via over the first portion, wherein the second portion includes a second width greater than the first width and a second set of opposing sidewall surfaces above the second dielectric layer;
• treating the second portion of the conductive through-via with an inorganic acid, thereby roughening the second set of opposing sidewall surfaces of the second portion of the conductive through-via while the first set of opposing sidewall surfaces of the first portion of the conductive through-via are protected by the second dielectric layer physically contacting the first portion of the conductive through-via;
• after treating the second portion of the conductive through-via with the inorganic acid, coupling a device die to the second dielectric layer;
• and
• after coupling the device die to the second dielectric layer, molding the device die and the conductive through-via in a molding material that physically contacts the device die, wherein the molding material is in direct contact with the roughened second set of opposing sidewall surfaces.