Seed metal delete process for thin film repair solutions using direct UV laser

• US 6,235,544 B1
• Filed: 04/20/1999
• Issued: 05/22/2001
• Est. Priority Date: 04/20/1999
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Wassick, Thomas A., Surprenant, Richard P., Wood, James P., Hendricks, Charles J., Franklin, Peter A., Tirch, Stephen J. III
• Primary Examiner(s): Tsai, Jey
• Assistant Examiner(s): STEVENSON, ANDRE C
• Application Number:
  US09/295,131
• Time in Patent Office: 763 Days
• Field of Search: 324/158.1, 522/172, 106/287.16, 264/104, 257/773, 257/776, 257/748, 252/500, 423/8, 427/123, 204/192.1, 438/14
• US Class Current: 438/14
• CPC Class Codes: H01L 21/485 Adaptation of interconnections, e.g. engineering charges, repair techniques

Abstract

A multilayer thin film structure (MLTF) is provided having no extraneous via-pad connection strap plated metallurgy for defective vias needing removal. The method for making or repairing the MLTF comprises determining interconnection defects in the MLTF at a thin film layer adjacent to the top metal layer of the structure, applying a top surface dielectric layer and forming vias in the layer, applying a metal conducting layer and removing the metal conducting layer for via-pad connection straps of defective vias and at the intersection of XY lines used in the repair, defining the top surface metallization including a series of orthogonal X conductor repair lines and Y conductor repair lines using a photoresist and lithography and then using a phototool to selectively expose the photoresist to define top surface strap connections needed to repair the interconnections and/or make EC'"'"'s, and forming the top surface metallization using additive or subtractive metallization techniques.

Claims

1. A method of forming a multilayer thin film structure (MLTF) which comprises a series of layers comprising a dielectric having metal thereon in the form of wiring and via interconnections and a top surface layer of the structure which has vias, chip connection pads, via-pad connection straps for only non-defective vias and a plurality of orthogonal X conductor lines and Y conductor lines and defined metal strap repair lines thereon comprising the steps of:

building the MLTF layer by layer up to a layer adjacent the top surface metal layer of the structure;

electrically testing and/or inspecting the layer adjacent to the top surface metal layer and determining faulty interconnections;

determining the interconnection defects at the thin film layer below and adjacent to the top surface layer of the MLTF structure;

defining the top surface connections needed to repair the defective interconnections based on the defects uncovered to determine the best metal line repair routes on the top surface layer;

applying a dielectric layer and forming vias in the layer;

applying a metal conducting layer on the dielectric layer and in the vias;

deleting the metal conducting layer for via-pad connection straps for vias determined to be defective and for X-Y orthogonal line intersections for X and/or Y lines which are determined to be top surface metal repair connections;

defining by a photoresist technique the top surface layer to form the top surface metallization as if no defects existed including a plurality of orthogonal X-Y repair lines;

defining metal routes for connecting pads of defective vias (nets) needing repair by first metal connecting line straps from the pad to an X repair line and/or a Y repair line and then connecting the connected X and/or Y repair line using the defined X and/or Y lines to a desired second pad by second metal connecting line straps from the X or Y repair line to the second pad by exposing the photoresist layer based on the defects uncovered to define the first and second metal connecting line straps; and

then developing and plating the top surface metallization layer to form the wiring including vias, chip connection pads, via-pad connection straps for only non-defective vias and a plurality of orthogonal X conductor lines and Y conductor lines and defined metal strap repair lines.

2. The method of claim 1 wherein the metal repair and/or engineering change lines are defined by a photo exposure tool controlled by an algorithm that analyzes the test data and determines the repair and/or engineering change wiring needed.

3. The method of claim 1 wherein deletion of the metal conducting layer is performed using a laser.

4. The method of claim 1 wherein the top surface metallization other than the repair strap is formed using a fixed mask.

5. A method for repairing defective via interconnections of multilayer thin film structures (MLTF) or making engineering changes (EC'"'"'s) to the structures which structures comprise a series of layers comprising a dielectric layer having plated metal thereon in the form of wiring and via interconnections to the next layer and a top layer of the structure which has interconnecting vias to the lower layers and corresponding chip connection pads connected to the vias by straps comprising the steps of:

building the MLTF layer by layer up to a layer adjacent the top surface metal layer of the structure;

electrically testing and/or inspecting the layer adjacent to the top surface metal layer and determining faulty interconnections;

determining the interconnection defects at the thin film layer below and adjacent to the top surface layer of the MLTF structure;

defining the top surface connections needed to repair the defective interconnections based on the defects uncovered and/or EC'"'"'s desired to determine the best metal line repair routes on the top surface layer;

applying a dielectric layer and forming vias in the layer;

applying a metal conducting layer on the dielectric layer and in the vias;

deleting the metal conducting layer for via-pad connection straps for vias determined to be defective and for X-Y orthogonal line intersections for X and/or Y lines which are determined to be top surface metal repair connections;

defining by a photoresist technique the top surface layer to form the top surface metallization as if no defects existed including a plurality of orthogonal X-Y repair lines;

defining metal routes for connecting pads of defective vias (nets) needing repair by first metal connecting line straps from the pad to an X repair line and/or a Y repair line and then connecting the connected X and/or Y repair line using the defined X and/or Y lines to a desired second pad by second metal connecting line straps from the X or Y repair line to the second pad by exposing the photoresist layer based on the defects uncovered and/or EC changes to define the first and second metal connecting line straps; and

then developing and plating the top surface metallization layer to form the wiring including vias, chip connection pads, via-pad connection straps for only non-defective vias and a plurality of orthogonal X conductor lines and Y conductor lines and defined metal strap repair lines.

6. The method of claim 5 wherein the repair straps are defined using a photo tool controlled by an algorithm that analyzes the test data and determines the repair strap wiring needed for the multilayer thin film structure.

7. The method of claim 5 wherein top surface metallization other than the repair straps is formed using a fixed mask.

8. The method of claim 5 wherein each thin film layer is tested and/or inspected after its fabrication to determine intralevel defects and repairing any such defects before the next layer is formed.

9. The method of claim 5 wherein the deletion of the metal conducting layer is performed using a laser.