Patent EP-2395543-A1 (EP)
Inventor: BUCKLEY JULIEN
IPC: H01L21/033
Filed: 2011-05-27
Abstract: The process of producing a cross grid of conductor or semiconductor lines on a substrate (2), comprises forming a first cavity of rectangular shape on the substrate, forming a second cavity of rectangular shape superimposed on the first cavity, covering the bottom of the resulting cavity of a first diblock copolymer layer comprising a network of lines formed by alternating lines of a first polymer and lines of second polymer, and removing lines of the first polymer to form an alternating first recess and lines of second polymer. The process of producing a cross grid of conductor or semiconductor lines on a substrate (2), comprises forming a first cavity of rectangular shape on the substrate, forming a second cavity of rectangular shape superimposed on the first cavity, covering the bottom of the resulting cavity of a first diblock copolymer layer comprising a network of lines formed by alternating lines of a first polymer and lines of second polymer, removing lines of the first polymer to form an alternating first recess and lines of second polymer, preparing a deposit of a layer of a first conductor or semiconductor material on the recess and lines of the second polymer, removing the lines of the second polymer covered by the first conductor or semiconductor material to prepare the first level of lines, selectively removing the materials forming the second cavity to make the bottom of the first accessible cavity partially covered along its width of the first level lines, depositing a layer of a second conductor or semiconductor material in the first cavity, covering the second conductor or semiconductor material layer by a second diblock copolymer comprising a network of lines formed by alternating lines of a third polymer and lines of fourth polymer, removing lines of the fourth polymer to form an alternating second bleeding and lines of third polymer, and removing from the second recess the second conductor or semiconductor material to prepare the second level lines. The grid comprises a first level of lines comprising first lines parallel to each other made of a conductor or semiconductor material on a grid insulator in a plane parallel to the substrate, and a second level of lines comprising second lines parallel to each other made of a conductor or semiconductor material above the first level of lines. The second lines are perpendicular to the first lines. The first and second cavities intersect at right angles to form a resultant cavity. The lines are arranged in parallel manner along the length of the second cavity, and perpendicular to the first line and second lines of polymers. The material comprising impedance switching properties is provided using a binary oxide, a solid electrolyte, perovskite made of ternary oxide, a phase change material, molecules or polymers having resistance switching characteristics, or a magnetic material forming a tunnel junction of magnetic or spin valve type, by application of an electric field. The first cavity has a width equal to a multiple of the gap of the second diblock copolymer. The second cavity has a width equal to a multiple of the gap of the first diblock copolymer. The step of forming the first cavity is followed by depositing a layer (4) of insulating material on the edges and bottom of the first cavity, and depositing, on the layer of insulating material, a layer of material able to be etched selectively with respect to lines of the second polymer and the insulating material. The step of forming of the second cavity comprises depositing a layer of material for selectively etching with respect to materials forming the bottom and edges of the first cavity, and removing a part of the material layer so that the bottom of the second cavity is formed by the bottom of the first cavity covered with the material of layer to be selectively etched with respect to the lines of the second polymer and the insulating material. The step of removal of lines of the first polymer is followed by a removal step through the first recess of the material able to be selectively etched with respect to the lines of the second polymer and the insulating material layer. The step of overlaying is carried out by depositing the layer of diblock copolymer, and separating the phases from the diblock copolymer deposited to obtain alternating lines of two different polymers. Each step of recovery is followed by structuring so that the first diblock copolymer is confined in the resulting cavity and/or the second diblock copolymer is confined to the first cavity. A neutralization film is deposited prior to the deposition of the first and/or second diblock copolymer. The step of depositing the second conductor or semiconductor material is followed by a step of chemical modification of the layer of second conductor or semiconductor material to obtain ends having a chemical affinity for second diblock copolymer phases. One of the first, second, third and fourth polymers of the first diblock copolymer has a volume composition of 0.35-0.65.