Method of forming semiconductor device
The present invention provides a semiconductor device and a method of forming the same, and the semiconductor device includes a substrate, a first interconnect layer and a second interconnect layer. The first interconnect layer is disposed on the substrate, and the first interconnect layer includes a first dielectric layer around a plurality of first magnetic tunneling junction (MTJ) structures. The second interconnect layer is disposed on the first interconnect layer, and the second interconnect layer includes a second dielectric layer around a plurality of second MTJ structures, wherein, the second MTJ structures and the first MTJ structures are alternately arranged along a direction. The semiconductor device may obtain a reduced size of each bit cell under a permissible process window, so as to improve the integration of components.
1 . A method of forming semiconductor device, comprising:
providing a substrate;
forming a first interconnect layer on the substrate, the first interconnect layer comprising a first dielectric layer around a plurality of first metal interconnections;
forming a second interconnect layer on the first interconnect layer, the second interconnect layer comprising a second dielectric layer around a plurality of second metal interconnections and a plurality of third metal interconnections, wherein the forming of the second metal interconnections and the third metal interconnections comprises:
forming a plurality of first mask patterns on the second dielectric layer, the first mask patterns being arranged with a first pitch;
forming a plurality of second mask patterns on the first mask patterns, the second mask patterns being arranged with a second pitch which is greater than the first pitch;
performing an etching process through the second mask patterns and the first mask patterns, to form a plurality of first openings throughout the second dielectric layer and a plurality of second openings disposed within the second dielectric layer; and
forming the second metal interconnections and the third metal interconnections in the first openings and the second openings;
forming a third interconnect layer on the second interconnect layer, the third interconnect layer comprising a third dielectric layer around a plurality of first magnetic tunneling junction (MTJ) structures;
forming a plurality of fourth metal interconnections in the third dielectric layer, the fourth metal interconnections and the first MTJ structures being alternately arranged in the third dielectric layer; and
forming a fourth interconnect layer on the third interconnect layer, the fourth interconnect layer comprising a fourth dielectric layer around a plurality of fifth metal interconnections and a plurality of second MTJ structures, the fifth metal interconnections and the second MTJ structures being alternately arranged in the fourth dielectric layer.
2 . The method of forming semiconductor device according to claim 1 , wherein a portion of the first metal interconnections is electrically connected to a source region disposed in the substrate.
3 . The method of forming semiconductor device according to claim 2 , wherein a width of each of the second metal interconnections is greater than a width of each of the third metal interconnections.
4 . The method of forming semiconductor device according to claim 1 , wherein the second metal interconnections formed in the second openings are electrically connected to a source region disposed in the substrate.
5 . The method of forming semiconductor device according to claim 4 , wherein a width of each of the second metal interconnections is the same as a width of each of the third metal interconnections.
6 . The method of forming semiconductor device according to claim 1 , wherein the fifth metal interconnections are disposed directly above the first MTJ structures disposed in the third interconnect layer, and the fourth metal interconnections are disposed directly below the second MTJ structures disposed in the fourth interconnect layer.
7 . The method of forming semiconductor device according to claim 1 , wherein a pitch of each of the first MTJ structures is greater than a pitch of the second metal interconnections or a pitch of the third metal interconnections.
8 . The method of forming semiconductor device according to claim 1 , wherein the second metal interconnection and a portion of the third metal interconnections are monolithic.