Use of underfill tape in microelectronic components, and microelectronic components with cavities coupled to through-substrate vias
A microelectronic component ( 110, 120 ) has a contact pad ( 110 C, 120 C, 920 C) recessed in a cavity ( 410 ) and covered by underfill tape ( 130 ). The cavity has a void ( 410 V) below the underfill tape. A protruding contact pad of another microelectronic component ruptures the underfill tape to enter the cavity and bond to the recessed contact pad. The void helps in rupturing the underfill tape, thus reducing the amount of underfill residue between the two contact pads and improving the contact resistance. Also provided is a microelectronic component having a substrate with a cavity and having a through-substrate via extending into the cavity. Other features are also provided.
1. A manufacturing method comprising:
obtaining a first microelectronic component comprising one or more first cavities and, for each first cavity, at least one first contact pad recessed in the first cavity, the first cavity comprising a void above the first contact pad;
attaching an underfill tape to the first microelectronic component, the underfill tape at least partially covering each first cavity's void; and
attaching a second microelectronic component to the first microelectronic component with the underfill tape between the first and second microelectronic components, wherein the second microelectronic component comprises one or more protruding second contact pads, and during the attaching of the second microelectronic component, each second contact pad enters a respective first cavity through the underfill tape and bonds to a respective first contact pad;
wherein during the attaching of the second microelectronic component, at least one second contact pad pushes the underfill tape into the respective first cavity's void and stretches the underfill tape inside the respective first cavity's void.
2. The method of claim 1 wherein the underfill tape is attached so that the underfill tape completely covers at least one first cavity.
3. The method of claim 1 wherein during the attaching of the second microelectronic component, at least one second contact pad creates or enlarges a hole in the underfill tape while the cavity has a void region underlying the second contact pad and the underfill tape.
4. The method of claim 1 wherein each of the first and second microelectronic components comprises a substrate and one or more through-substrate vias (TSV) each of which is a conductive via passing through the substrate;
wherein each protruding second contact pad is provided by a respective TSV in the second microelectronic component or by the second microelectronic component's circuit element underlying the respective TSV; and
wherein each first contact pad is provided by a respective TSV in the first microelectronic component or by the first microelectronic component's circuit element overlying the respective TSV.
5. The method of claim 1 wherein the second microelectronic component comprises one or more first cavities on the side opposite to the one or more protruding second contact pads, and for each first cavity, the second microelectronic component comprises at least one first contact pad recessed in the first cavity, the first cavity comprising a void above the first contact pad;
wherein the method further comprises:
attaching an underfill tape to the second microelectronic component, the underfill tape at least partially covering the void in each first cavity of the second microelectronic component;
obtaining a third microelectronic component comprising one or more protruding second contact pads;
attaching the third microelectronic component to the second microelectronic component, wherein during the attaching of the third microelectronic component, each second contact pad of the third microelectronic component enters a respective first cavity of the second microelectronic component through the underfill tape at least partially covering the void in each first cavity of the second microelectronic component and bonds to a respective first contact pad of the second microelectronic component.
6. The method of claim 1 wherein at least one first cavity comprises fusible material partially filling the first cavity, the first cavity's void comprising a region located directly above the fusible material and directly below the underfill tape.
7. The method of claim 6 wherein the fusible material is provided in the first cavity before attaching the underfill tape.
8. A structure formed by the method of claim 1 .
9. The structure of claim 8 further comprising a second microelectronic component attached to the first microelectronic component with the underfill tape disposed between the first and second microelectronic components, wherein the second microelectronic component comprises one or more protruding second contact pads each of which extends into a respective first cavity through the underfill tape and is bonded to a respective first contact pad.
10. The structure of claim 8 wherein each of the first and second microelectronic components comprises a substrate and one or more through-substrate vias (TSVs) each of which is a conductive via passing through the substrate;
wherein each protruding second contact pad is a region of a respective TSV in the second microelectronic component or of the second microelectronic component's circuit element underlying the respective TSV; and
wherein each first contact pad is a region of a respective TSV in the first microelectronic component or of the first microelectronic component's circuit element overlying the respective TSV.
11. The structure of claim 8 wherein the first and second microelectronic components are part of a plurality of at least three microelectronic components M 1 , M 2 , . . . , Mn each of which comprises a substrate and one or more through-substrate vias (TSV) each of which is a conductive via passing through the substrate;
wherein the first microelectronic component is one of components M 2 through Mn, and the second microelectronic component is one of M 1 through Mn− 1 ;
wherein each microelectronic component M 2 through Mn comprises one or more first cavities and, for each first cavity, at least one first contact pad recessed in the first cavity, the first cavity comprising a void above the first contact pad;
wherein each microelectronic component M 1 through Mn− 1 comprises one or more protruding second contact pads;
wherein the method comprises attaching each component Mi (i= 1 through n− 1 ) to component Mi+ 1 with the underfill tape on component Mi+ 1 being between the components Mi and Mi+ 1 , wherein during the attaching of each component Mi each second contact pad of the component Mi+ 1 enters a respective first cavity of the component Mi through the underfill tape on component Mi and bonds to a respective first contact pad of component Mi+ 1 .
12. The method of claim 1 wherein the underfill tape comprises a dry tape.
13. The method of claim 1 wherein the underfill tape comprises a combination of dry and liquid layers.
14. The method of claim 1 wherein at a conclusion of the attaching of the underfill tape, said at least one first contact pad is exposed in the void.
15. The method of claim 1 further comprising, before the attaching of the underfill tape, partially filling the cavity by conductive material;
wherein at a conclusion of the attaching of the underfill tape, the conductive material is exposed in the void.