Forming via holes in a multilevel substrate in a single step

A method of forming conductive vias in a multilevel substrate, including forming every via hole to receive a conductor in a single step, comprising the following steps in the sequence set forth:

• disposing a first layer comprising first horizontal copper lines covered by a first polymer on a base;
• disposing a second layer comprising second horizontal copper lines covered by a second polymer on the first layer such that a portion of each first copper line is not beneath any second copper line;
• forming a plurality of vertical via holes in the top of the second polymer by applying an etch, the polymers and copper lines having sufficiently different physical properties to assure that the etch attacks the polymers but is blocked by the copper lines without deforming the copper lines to any significant degree whereby the copper lines provide a barrier to the etch, so as to form all the via holes in the substrate in a single etch step wherein some via holes extend through only the second polymer and terminate at the top surfaces of the second copper lines while other via holes extend through both the first and second polymers and terminate at the top surfaces of said portions of the first copper lines, thereby exposing both the first and second copper lines;
• and
• depositing a conductive material in all the via holes to form conductive vias from the first and second copper lines to the top of the second polymer.

A method of forming every via hole in a multilevel substrate in a single step, comprising the following steps in the sequence set forth:

• depositing a plurality of first metal lines on a base;
• depositing a first dielectric layer over the first metal lines;
• depositing a plurality of second metal lines on the first dielectric layer such that selected first metal lines comprise uncovered portions without any second metal line directly above;
• depositing a second dielectric layer over the second metal lines;
• and then
• forming via holes by applying an etch, the dielectrics and metal lines having sufficiently different physical properties to assure that the etch attacks the dielectrics but is blocked by the metal lines without deforming the metal lines to any significant degree whereby the metal lines provide a barrier to the etch thereby forming via holes at the top of the second dielectric which extend through the second dielectric and terminate at the top surfaces of selected second metal lines concurrently with forming other via holes which extend through the second dielectric and the first dielectric and terminate at the top surfaces of the uncovered portions of the first metal lines, thereby forming each of the via holes in the substrate with a single etch in a single step.

A method of forming every via hole in a multilevel substrate in a single step, comprising:

• depositing a plurality of first metal lines on a base;
• depositing a first dielectric layer over the first metal lines and base;
• depositing a plurality of second metal lines on the first dielectric layer such that each first metal line comprises an uncovered portion without any second metal line above;
• depositing a second dielectric layer over the second metal lines and the first dielectric layer;
• depositing a plurality of third metal lines on the second dielectric layer such that each second metal line comprises an uncovered portion without any third metal line above and the uncovered portions of the first metal lines are not covered by any third metal line;
• depositing a third dielectric layer over the third metal lines and the second dielectric layer;
• depositing a plurality of fourth metal lines on the third dielectric layer such that each third metal line comprises an uncovered portion without any fourth metal line above, and the uncovered portions of the second and first metal lines are not covered by any fourth metal line;
• depositing a fourth dielectric layer over the fourth metal lines and the third dielectric layer;
• and
• forming each of the via holes in the substrate in a single step by applying an etch, the dielectrics and metal lines having sufficiently different physical properties to assure that the etch attacks the dielectrics but is blocked by the metal lines without deforming the metal lines to any significant degree whereby the metal lines provide a barrier to the etch, so that the via holes extend from the top of the fourth dielectric layer to the top surfaces of the fourth metal lines and the top surfaces of uncovered portions of the third, second and first metal lines wherein separate via holes extend to separate metal lines.

A method of forming every via hole in a multilevel substrate in a single step, comprising the following steps in the sequence set forth:

• depositing a plurality of first horizontal copper lines on a planar base;
• depositing a first planar dielectric layer over the first copper lines and the base;
• depositing a plurality of second horizontal copper lines, approximately orthogonal to the first copper lines, on the first dielectric layer such that portions of each first copper line are not directly below any second copper line;
• depositing a second planar dielectric layer over the second copper lines and the first dielectric layer;
• and
• forming vertical via holes by applying an etch, the dielectrics and copper lines having sufficiently different physical properties to assure that the etch attacks the dielectrics but is blocked by the copper lines whereby the copper lines provide an etch stop, with some vertical via holes extending through only the second dielectric to expose the top surfaces of second copper lines and other vertical via holes extending through both the second dielectric and the first dielectric to expose the top surfaces of said portions of the first copper lines without deforming any copper lines, thereby forming each of the via holes in the substrate in a single step.