Apparatus and method for alignment of members to electron beams

Claim 2

In the process of aligning an electron beam pattern projected from a photocathode with selected areas of a member with a high degree of precision by reference to at least two relatively widely separated registration indicia of predetermined shape formed on the member, the steps comprising: a. causing separated aligning electron beams to be projected from the photocathode for each registration indicia on the member, each aligning electron beam being of substantially the same cross sectional shape as its respective registration indicia, b. causing an electrical signal to be developed at each indicia proportional to the amount of the area of the registration indicia impinged by its respective aligning electron beam, c. moving the alignment electron beam with respect to its respective registration indicia so that the electrical signal therefrom varies, d. positioning one aligning electron beam at the point where the electrical signal indicates the optimum coincidence of the alignment electron beam with its respective registration indicia, and e. using the position of said one aligning electron beam with its respective registration indicia as a fixed center, electromagnetically moving the second aligning electron beam both in an arc and radially with respect to said center until the resulting electrical signal indicates optimum coincidence of said second alignment electron beam with its respective registration indicia whereby both the shape and area of the photocathode pattern corresponds precisely to the selected area of the member.

Claim 3

The process of claim 1 wherein the electrical signals derived from the two indicia when the aligning electron beams impinge thereon operate electromagnetic means for shifting each of the electron beams with respect to the indicia so as to center each aligning electron beam in the indicia and coincide in their cross-sections.

Claim 4

The process of claim 2 wherein the electrical signals derived from the indicia when the aligning electron beams impinge thereon control an electromagnetic means to shift one electron beam in the X and Y directions and the other electron beam and the photocathode electron beam is rotated in the theta direction, using the first registration indicia as a center, with respect to the indicia.

Claim 5

The process of claim 3 wherein the relative motion of the aligning electron beam to the registration indicia is terminated and the alignment electron beam is held at the point of maximum coincidence thereof.

Claim 6

In apparatus for exposing precisely located areas of a member to an electron beam pattern, a photocathode source of a beam of electrons including at least two separated alignment beam portions of predetermined cross-sectional shape, means for positioning the member in a spaced relation to the photocathode source of the beam of electrons, means for applying a potential between the member and the source whereby electrons from the photocathode source are directed to and impinge on the member, electromagnetic means for directing the beam of electrons from the source so as to cause the beam of electrons to impinge on a selected portion of the member close to the desired precisely located area, the memBer having at least two separated registration indicia in its surface, each registration indicia being of a shape closely similar to the cross-sectional shape of the alignment beam portion, the registration indicia giving rise to an electrical signal when an alignment beam portion impinges thereon, the electrical signal varying with the amount of the area of impingement, the electromagnetic means directing each of the alignment beam portions into the vicinity of a respective registration indicia on the member and into approximate coincidence thereof, and electronic circuit means responsive to said electrical signals to effect a fine adjustment of the position of each of the respective alignment beam portions to the registration indicia of the member so as to cause the electron beam portions to substantially coincide with the respective registration indicia whereby the beam of electrons from the photocathode is precisely located and oriented with respect to the member so that precisely located areas thereof can then be exposed to the electron beam from the photocathode.

Claim 7

In apparatus for exposing precisely located areas of a member to an electron beam pattern, a photocathode source of a beam of electrons including at least two separated alignment beam portions of predetermined cross-sectional shape, means for positioning the member in a spaced relation to the photocathode source of the beam of electrons, means for applying a potential between the member and the source whereby electrons from the photocathode source are directed to and impinge on the member, electromagnetic means for directing the beam of electrons from the source so as to cause the beam of electrons to impinge on a selected portion of the member close to the desired precisely located area, the memBer having at least two separated registration indicia in its surface, each registration indicia being of a shape closely similar to the cross-sectional shape of the alignment beam portion, the registration indicia giving rise to an electrical signal when an alignment beam portion impinges thereon, the electrical signal varying with the amount of the area of impingement, the electromagnetic means directing each of the alignment beam portions into the vicinity of a respective registration indicia on the member and into approximate coincidence thereof, and electronic circuit means responsive to said electrical signals to effect a fine adjustment of the position of each of the respective alignment beam portions to the registration indicia of the member so as to cause the electron beam portions to substantially coincide with the respective registration indicia whereby the beam of electrons from the photocathode is precisely located and oriented with respect to the member so that precisely located areas thereof can then be exposed to the electron beam from the photocathode.

Claim 8

The apparatus of claim 5, wherein the means to produce electrical signals proportional to the degree of coincidence of the alignment electron beams with their respective registration indicia includes a first registration indicia producing electrical signals upon impingement of the aligning electron beam thereon which affect the electronic circuit means to actuate the electromagnet means to move that aligning electron beam in X and Y directions with respect to the first registration indicia so as to cause the first aligning electron beam to coincide substantially exactly with the registration indicia, and the second registration indicia producing electrical signals to affect the electronic means to actuate the electromagnet means to rotate the second aligning electronic beam in an arc about the first registration indicia as a center whereby to cause the second electron beam to coincide substantially exactly with the second registration indicia, thereby effecting substantial exactness of impingement of the entire source electron beam on the desired areas of the member.

Claim 9

The apparatus of claim 6, wherein means are provided for oscillating the alignment electron beams so as to provide for varying amounts of coincidence of the alignment electron beams with their respective registration indicia, thereby producing varying electrical signals related to the amount of coincidence, the resulting variable electrical signals controlling the actuation of the means to effect a fine adjustment so as to cause the alignment electron beams to approach and locate a point of optimum coincidence with their respective registration indicia.

Claim 10

In apparatus for exposing precisely located areas of a member to an electron beam pattern, a photocathode source of a beam of electrons including at least one alignment beam portion of predetermined cross-sectional shape, means for positioning the member in a spaced relation to the source of the beam of electrons, means for applying a potential between the member and the source whereby electrons from the source are directed to and impinge on the member, electromagnetic means for directing the beam of electrons from the source so as to cause the beam of electrons to impinge on a selected portion of the member close to the desired precisely located area, the member having at least one registration indicia in its surface of a shape closely similar to the cross-sectional shape of the alignment beam portion, the electromagnetic means directing the alignment beam portion into the vicinity of the registration indicia on the member and into approximate coincidence thereof, means for oscillating the alignment electron beam with respect to the registration indicia to produce varying amounts of coincidence thereof, means for generating a variable electrical signal proportional to such coincidence, means to effect a fine adjustment of the position of the alignment beam to the registration indicia of the member so as to cause the electron beam to substantially coincide with the registration indicia, and means operable by the variable electrical signal for controlling the means to effect the fine adjustment whereby to control the means for oscillating the alignment electron beam to cause the alignment electron beam to approach and locate a point of optimum coincidence with its associated registration indicia whereby the member is precisely located with respect to the beam of electrons from the photocathode and the precisely located areas thereof can then be exposed to the electron beam from the photocathode.

Claim 11

In apparatus for exposing precisely located areas of a member to an electron beam pattern, a photocathode source of a beam of electrons including at least one alignment beam portion of predetermined cross-sectional shape, means for positioning the member in a spaced relation to the source of the beam of electrons, means for applying a potential between the member and the source whereby electrons from the source are directed to and impinge on the member, electromagnetic means for directing the beam of electrons from the source so as to cause the beam of electrons to impinge on a selected portion of the member close to the desired precisely located area, the member having at least one registration indicia in its surface of a shape closely similar to the cross-sectional shape of the alignment beam portion, the electromagnetic means directing the alignment beam portion into the vicinity of the registration indicia on the member and into approximate coincidence thereof, means for oscillating the alignment electron beam with respect to the registration indicia to produce varying amounts of coincidence thereof, means for generating a variable electrical signal proportional to such coincidence, means to effect a fine adjustment of the position of the alignment beam to the registration indicia of the member so as to cause the electron beam to substantially coincide with the registration indicia, and means operable by the variable electrical signal for controlling the means to effect the fine adjustment whereby to control the means for oscillating the alignment electron beam to cause the alignment electron beam to approach and locate a point of optimum coincidence with its associated registration indicia whereby the member is precisely located with respect to the beam of electrons from the photocathode and the precisely located areas thereof can then be exposed to the electron beam from the photocathode.

Claim 12

The apparatus of claim 8, wherein the fine adjustment means terminates the operation of the oscillating means at the time of maximum coincidence of the alignment electron beams with their registration indicia.

Claim 13

In an apparatus for precisely aligning a patterned beam of electron beam radiation which includes two aligning radiation beams, with a selected area on a member having two registration area marks thereon complementary to the aligning beams, means for directing the point of impingement of the patterned electron beam of radiation on the member, electrical circuit means including signal generators associated with each of the marks producing signals varying with the degree of coincidence of each beam to its registration mark, the circuit including electrically operable means to cause the beam of radiation to move in a controlled path, an oscillation generator connected to said electrically operable means to cause the aligning beams to move in such predetermined path with respect to the registration marks, whereby a variable signal is produced, electronic means responsive to the variable signals to produce error signals, and servo mechanisms responsive to the error signals to said electrically operable means to cause each of the aligning beams to approach coincidence with their respective registration marks, and means in said circuit means to terminate the operation of the oscillator generator when coincidence of the aligning radiation beam to their respective registration marks is reached.

Claim 14

In an apparatus for precisely aligning a patterned beam of electron beam radiation which includes two aligning radiation beams, with a selected area on a member having two registration area marks thereon complementary to the aligning beams, means for directing the point of impingement of the patterned electron beam of radiation on the member, electrical circuit means including signal generators associated with each of the marks producing signals varying with the degree of coincidence of each beam to its registration mark, the circuit including electrically operable means to cause the beam of radiation to move in a controlled path, an oscillation generator connected to said electrically operable means to cause the aligning beams to move in such predetermined path with respect to the registration marks, whereby a variable signal is produced, electronic means responsive to the variable signals to produce error signals, and servo mechanisms responsive to the error signals to said electrically operable means to cause each of the aligning beams to approach coincidence with their respective registration marks, and means in said circuit means to terminate the operation of the oscillator generator when coincidence of the aligning radiation beam to their respective registration marks is reached.