Interconnect metal openings through dielectric films
A semiconductor die includes a semiconductor body having a gate, a source contact, and a drain contact thereon, a metal contact structure on the semiconductor body and electrically connected to the gate, the source contact, or the drain contact, and an encapsulation structure. The encapsulation structure includes first and second encapsulation layers of respective non-conductive materials stacked on the metal contact structure, and an opening extending therethrough to expose the metal contact structure. The opening includes a sidewall having a substantially continuous slope that extends through the first and second encapsulation layers to the metal contact structure. Related devices and fabrication methods are also discussed.
1 . A semiconductor die, comprising:
a semiconductor body comprising a gate, a source contact, and a drain contact thereon;
a metal contact structure comprising first and second metal layers stacked on the semiconductor body in a first direction and electrically connected to the gate, the source contact, or the drain contact, wherein the second metal layer is directly on the first metal layer; and
an encapsulation structure comprising first and second encapsulation layers of respective non-conductive materials stacked on the metal contact structure in the first direction, and an opening extending therethrough to expose the metal contact structure at a bottom of the opening,
wherein the metal contact structure is between the encapsulation structure and the semiconductor body in the first direction, and the first metal layer is between the second metal layer and the semiconductor body in the first direction,
wherein the opening comprises a sidewall that extends through the first and second encapsulation layers and through the second metal layer to expose the first metal layer at the bottom of the opening, and a slope of the sidewall does not vary by more than about 30 degrees, and
wherein edges of the first encapsulation layer, the second encapsulation layer, and the second metal layer adjacent the opening have first, second, and third slopes, respectively, and wherein the second slope is different than the first slope.
2 . The semiconductor die of claim 1 , wherein the first encapsulation layer is between the second encapsulation layer and the metal contact structure, the sidewall comprises the edge of the second encapsulation layer having the second slope adjacent the opening, and the slope of the sidewall comprises the second slope.
3 . The semiconductor die of claim 2 , wherein the opening extends through the second metal layer to a surface of the first metal layer.
4 . The semiconductor die of claim 3 , wherein the sidewall further comprises the edge of the first encapsulation layer having the first slope adjacent the opening, and the slope of the sidewall further comprises the first slope.
5 . The semiconductor die of claim 4 , wherein the sidewall further comprises the edge of the second metal layer having the third slope adjacent the opening that is less than or equal to the first slope, and the slope of the sidewall further comprises the third slope.
6 . The semiconductor die of claim 1 , wherein the second slope is greater than the first slope.
7 . The semiconductor die of claim 6 , wherein the first, second, and third slopes are negative slopes, or the first, second, and third slopes are positive slopes.
8 . The semiconductor die of claim 5 , wherein the edges of the second metal layer, the first encapsulation layer, and the second encapsulation layer define respective angles of about 35 to 55 degrees relative to a normal to the surface of the first metal layer.
9 . The semiconductor die of claim 8 , wherein the first, second, and third slopes do not vary by more than about 10 degrees.
10 . The semiconductor die of claim 6 , wherein the edge of the second encapsulation layer extends towards the opening beyond the edge of the first encapsulation layer in a second direction that is perpendicular to the first direction.
11 . The semiconductor die of claim 10 , wherein the sidewall comprising the edge of the second encapsulation layer extends along the edge of the first encapsulation layer and on an interface between the first encapsulation layer and the second metal layer.
12 . The semiconductor die of claim 11 , wherein an edge of the second metal layer adjacent the opening is covered by the second encapsulation layer, and the sidewall comprising the edge of the second encapsulation layer directly contacts the surface of the first metal layer.
13 . The semiconductor die of claim 1 , wherein the first encapsulation layer comprises SiO 2 , SiN, SiON, and/or Al 2 O 3 , and wherein the second encapsulation layer comprises polyimide, benzocyclobutene (BCB), borosilicate glass (BSG), polyamide, polybenzoxazole (PBO), and/or a photoresist material.
14 . The semiconductor die of claim 1 , wherein the sidewall defines an angle of about 40 to 50 degrees relative to a surface of the metal contact structure.
15 . A semiconductor die, comprising:
a semiconductor body comprising a gate, a source contact, and a drain contact thereon;
a metal contact structure on the semiconductor body and electrically connected to the gate, the source contact, or the drain contact; and
an encapsulation structure comprising first and second encapsulation layers of respective non-conductive materials stacked on a surface of the metal contact structure in a first direction such that the metal contact structure is between the encapsulation structure and the semiconductor body in the first direction, and an opening extending therethrough to expose a portion of the surface of the metal contact structure,
wherein the first encapsulation layer is stacked between the second encapsulation layer and the metal contact structure in the first direction, wherein edges of the first and second encapsulation layers are adjacent the opening, and wherein the edge of the second encapsulation layer extends beyond the edge of the first encapsulation layer towards the opening in a second direction that is perpendicular to the first direction.
16 . The semiconductor die of claim 15 , wherein the opening comprises a sidewall that extends through the first and second encapsulation layers to the metal contact structure, and wherein the sidewall comprises the edge of the second encapsulation layer.
17 . The semiconductor die of claim 16 , wherein the metal contact structure comprises a first metal layer and a second metal layer between the first metal layer and the encapsulation structure, and wherein the opening extends through the second metal layer to a surface of the first metal layer.
18 . The semiconductor die of claim 17 , wherein the sidewall comprising the edge of the second encapsulation layer extends along the edge of the first encapsulation layer and on an interface between the first encapsulation layer and the second metal layer.
19 . The semiconductor die of claim 17 , wherein an edge of the second metal layer adjacent the opening is covered by the second encapsulation layer, and the sidewall comprising the edge of the second encapsulation layer directly contacts the surface of the first metal layer.
20 . The semiconductor die of claim 16 , wherein the sidewall defines an angle of about 35 to 55 degrees relative to a surface of the metal contact structure.
21 . A method of fabricating a transistor device, comprising:
providing a semiconductor body;
forming a metal contact structure comprising first and second metal layers stacked on the semiconductor body in a first direction with the second metal layer directly on the first metal layer, wherein the first metal layer is between the second metal layer and the semiconductor body in the first direction;
forming an encapsulation structure comprising first and second encapsulation layers of respective non-conductive materials stacked on the metal contact structure in the first direction, wherein the metal contact structure is between the encapsulation structure and the semiconductor body in the first direction; and
forming an opening extending through the first and second encapsulation layers to expose the metal contact structure at a bottom of the opening, wherein the opening comprises a sidewall that extends through the first and second encapsulation layers and the second metal layer to expose the first metal layer at the bottom of the opening, and a slope of the sidewall does not vary by more than about 30 degrees, and
wherein edges of the first encapsulation layer, the second encapsulation layer, and the second metal layer adjacent the opening have first, second, and third slopes, respectively, and wherein the second slope is different than the first slope.
22 . The method of claim 21 ,
wherein the first encapsulation layer is between the second encapsulation layer and the metal contact structure, the sidewall comprises the edge of the second encapsulation layer having the second slope adjacent the opening, and the slope of the sidewall comprises the second slope,
wherein the opening extends through the second metal layer to a surface of the first metal layer,
wherein the sidewall further comprises the edge of the first encapsulation layer having the first slope adjacent the opening, and the slope of the sidewall further comprises the first slope, and
wherein forming the opening comprises:
patterning the second encapsulation layer to expose a portion of the first encapsulation layer;
performing a first etching operation to remove the portion of the first encapsulation layer and expose a portion of the second metal layer; and
performing a second etching operation to remove the portion of the second metal layer and expose the surface of the first metal layer.
23 . The method of claim 22 , wherein, responsive to the first and second etching operations, the second slope is greater than the first slope.
24 . The method of claim 23 , wherein at least one of the first or second etching operations comprises a passivation gas and is configured to remove the portion of the first encapsulation layer or the second metal layer, respectively, without substantial lateral etching of the edge of the second encapsulation layer.
25 . The method of claim 21 , wherein the first encapsulation layer is between the second encapsulation layer and the metal contact structure, the sidewall comprises the edge of the second encapsulation layer having the second slope adjacent the opening, and the slope of the sidewall comprises the second slope,
wherein the opening extends through the second metal layer to a surface of the first metal layer,
wherein the sidewall further comprises the edge of the first encapsulation layer having the first slope adjacent the opening, and the slope of the sidewall further comprises the first slope, and
wherein the edge of the second encapsulation layer extends beyond the edge of the first encapsulation layer in a second direction that is perpendicular to the first direction.
26 . The method of claim 25 , wherein the sidewall comprising the edge of the second encapsulation layer extends along the edge of the first encapsulation layer and on an interface between the first encapsulation layer and the second metal layer.
27 . The method of claim 26 , wherein forming the opening comprises:
performing a first etching operation to remove a portion of the first encapsulation layer and expose a portion of the second metal layer;
performing a second etching operation to remove the portion of the second metal layer and expose the surface of the first metal layer;
forming the second encapsulation layer on the first encapsulation layer and on the surface of the first metal layer; and
patterning the second encapsulation layer to expose the surface of the first metal layer.
28 . The method of claim 27 , wherein the second encapsulation layer comprises a photosensitive material, and wherein patterning the second encapsulation layer comprises photolithographically patterning the second encapsulation layer to expose the surface of the first metal layer.
29 . A semiconductor die, comprising:
a semiconductor body comprising a gate, a source contact, and a drain contact thereon;
a metal contact structure on the semiconductor body and electrically connected to the gate, the source contact, or the drain contact; and
an encapsulation structure comprising first and second encapsulation layers of respective non-conductive materials stacked on the metal contact structure in a first direction, and an opening extending therethrough to expose the metal contact structure at a bottom of the opening, wherein the metal contact structure is between the encapsulation structure and the semiconductor body in the first direction, and wherein the second encapsulation layer is directly on the first encapsulation layer,
wherein the opening comprises a sidewall having a substantially continuous slope that extends through the first and second encapsulation layers to the metal contact structure, and
wherein the sidewall defines an angle of about 35 to 55 degrees relative to a surface of the metal contact structure and comprises edges of the first and second encapsulation layers having first and second slopes that differ.
30 . The semiconductor die of claim 29 , wherein the first encapsulation layer is stacked in the first direction between the second encapsulation layer and the metal contact structure, and the second slope is greater than the first slope.
31 . The semiconductor die of claim 30 , wherein the edge of the second encapsulation layer extends beyond the edge of the first encapsulation layer in a second direction that is perpendicular to the first direction, and wherein the substantially continuous slope does not vary by more than about 30 degrees.
32 . The semiconductor die of claim 29 , wherein the first encapsulation layer comprises a first material, the second contact layer comprises a second material that is different from the first material, and the second slope transitions to the first slope at an interface between the second encapsulation layer and the first encapsulation layer.