Methods suitable for use in or in connection with the production of microelectronic devices

Claim 2

In method for producing microelectronic devices wherein an electron beam which is accurately deflectable over a limited field forms a predetermined pattern in a layer of organic resist material on a substrate and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the method of registering the microelectronic device comprising the step of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is at least one alignment mark among the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of said alignment marks by detecting the secondary electron emission image produced from the electron beam at at least one edge of an alignment mark, and selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to said alignment mark.

Claim 3

The method of claim 1 fUrther including the steps of aligning the electron beam by reference to each of the alignment marks by detecting the secondary electron emission image produced from the electron beam over a region of the mark embracing two edges of the mark, and processing the image by multiplying the image S produced at each position x on the region of the mark by a signal representing the value x, integrating the product so formed to produce an integral Integral Sxdx, integrating the image S itself to produce an integral Integral Sdx, and dividing the integral Integral Sxdx by the integral Integral Sdx to provide a value x of the mean position between the two edges, the position of said pattern having a predetermined fixed spatial relationship to the mean position x.

Claim 4

In a method of producing a device mask suitable for use in the production of a microelectronic device wherein the device mask includes a substrate having a body of solid transparent material carrying a layer of solid etchable, non-transparent material, wherein an electronic beam which is accurately deflectable over a limited field forms a predetermined pattern on a layer of organic resist material on said substrate and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the improvement comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is always at least one alignment mark of the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of the alignment marks by detecting the secondary electron emission produced from the electron beam at at least one edge of an alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to the mark, and forming said corresponding pattern by selectively etching said solid etchable non-transparent material through said layer of resist material after said electron beam has been scanned across said layer of resist material.

Claim 5

In a method of producing a device mask suitable for use in the production of a microelectronic device wherein the device mask includes a substrate having a body of solid transparent material carrying a layer of solid etchable, non-transparent material, wherein an electronic beam which is accurately deflectable over a limited field forms a predetermined pattern on a layer of organic resist material on said substrate and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the improvement comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is always at least one alignment mark of the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of the alignment marks by detecting the secondary electron emission produced from the electron beam at at least one edge of an alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to the mark, and forming said corresponding pattern by selectively etching said solid etchable non-transparent material through said layer of resist material after said electron beam has been scanned across said layer of resist material.

Claim 6

The method of claim 3 wherein the layer of solid etchable material is made of chromium.

Claim 7

In a method of producing a surface acoustic wave device wherein the surface acoustic wave device includes a substrate having a body of material capable of supporting surface acoustic waves carrying a layer of etchable material suitable for surface acoustic wave transducers, wherein an electron beam which is accurately deflectable over a limited field forms a predetermined pattern in a layer of organic resist material on a substrate, and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the improvement comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is always at least one alignment mark of the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of the alignment mark by detecting the secondary electron emission image produced from the electron beam at at least one edge of the alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to the mark, and forming said corresponding pattern by selectively etching said layer of etchable material through said layer of resist material after scanning said electron beam across said layer of resist material.

Claim 8

In a method of producing a surface acoustic wave device wherein the surface acoustic wave device includes a substrate having a body of material capable of supporting surface acoustic waves carrying a layer of etchable material suitable for surface acoustic wave transducers, wherein an electron beam which is accurately deflectable over a limited field forms a predetermined pattern in a layer of organic resist material on a substrate, and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the improvement comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is always at least one alignment mark of the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of the alignment mark by detecting the secondary electron emission image produced from the electron beam at at least one edge of the alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to the mark, and forming said corresponding pattern by selectively etching said layer of etchable material through said layer of resist material after scanning said electron beam across said layer of resist material.

Claim 9

In the method for producing a semiconductor integrator circuit wherein the substrate includes a body of semiconductor material having a layer of electrical insulator material on which a layer of organic resist material is formed, wherein an electron beam which is accurately deflectable over a limited field forms a predetermined pattern on the layer of organic resist material on said substrate and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the method of registering the semiconductor integrated circuit comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is at least one alignment mark along the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of said alignment marks by detecting the secondary electron emission image produced from the electron beam at at least one edge of an alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to said alignment mark, and forming said corresponding pattern by selectively etching said layer of electrical insulator material through said layer of organic resist material.

Claim 10

In the method for producing a semiconductor integrator circuit wherein the substrate includes a body of semiconductor material having a layer of electrical insulator material on which a layer of organic resist material is formed, wherein an electron beam which is accurately deflectable over a limited field forms a predetermined pattern on the layer of organic resist material on said substrate and wherein portions of the layer of resist material are selectively removed to form a corresponding pattern for the purpose of processing the substrate, the method of registering the semiconductor integrated circuit comprising the steps of: providing on the layer of resist material a plurality of alignment marks so located on the layer that when the layer is in a desired position for exposure by the electron beam there is at least one alignment mark along the plurality of alignment marks in the field of accurate deflection of the electron beam, aligning the electron beam by reference to each of said alignment marks by detecting the secondary electron emission image produced from the electron beam at at least one edge of an alignment mark, selectively scanning the electron beam across the layer in the field of accurate deflection of the electron beam to draw the predetermined pattern, the position of the pattern having a predetermined fixed spatial relationship to said alignment mark, and forming said corresponding pattern by selectively etching said layer of electrical insulator material through said layer of organic resist material.

Claim 11

The method of claim 6 wherein said semiconductor material is silicon and said electrical insulator material is silicon dioxide.

Claim 12

The method of claim 6 further including the steps of providing a further plurality of alignment marks on the surface of the substrate carrying the layer of electrical insulator material, detecting the secondary electron emission image produced from the electron beam at the marks belonging to the further plurality of alignment marks, and correcting the position of the electron beam at each mark belonging to the first plurality by reference to the secondary electron emission image at the marks belonging to the said further plurality of alignment marks.

Claim 13

The method of claim 6 wherein the alignment marks are made from a layer of a noble metal.