Apparatus for the exact mutual alignment of a mask and semiconductor wafer in a lithographic apparatus

Claim 1

In an arrangement for exact, mutual alignment of a mask and a semiconductor wafer in a lithographic apparatus which utilizes parallel particle beams impinging on a structured mask and then into the semiconductor wafer to be structured, said apparatus including means for positioning the mask in the beam path including a first retaining plate having first means for securing, a first group of setting pins extending perpendicular from the plate and parallel to the beam path and being secured to a table, a second group of three setting pins being mounted for displacement in a first controllable drive mechanism secured on a mounting part which is secured on said table, said second group being arranged to extend parallel to the plane of the mask and being actuated to move the first retaining plate parallel to a first coordinate axis, parallel to a second coordinate axis and to also rotate the plate in the plane, the improvements comprising the first group of setting pins being mounted for displacement in a second controllable drive mechanism secured on said mounting part.

Claim 9

A method for aligning a mask perpendicular to a direction of a particle beam in an apparatus having means for mounting the mask including a first retaining plate having a fastening means for securing the mask thereto, said first retaining plate being mounted on a table being movable at least between a first and second position, said method including securing the mask with the fastening means on the first retaining plate, observing adjustment marks with optical devices to obtain setting signals for the first position of the table, utilizing the setting signals to adjust the position of the first retaining plate and mask relative to the table to be in the focus plane of the optical devices, then shifting the table in a perpendicular direction to the direction of the particle beam to a second position, observing a second adjustment mark at the second position to obtain additional setting signals which serve for the adjustment of the mask into the focal plane of the optical devices.

Claim 10

A method for aligning a mask perpendicular to a direction of a particle beam in an apparatus having means for mounting the mask including a first retaining plate having a fastening means for securing the mask thereto, said first retaining plate being mounted on a table being movable at least between a first and second position, said method including securing the mask with the fastening means on the first retaining plate, observing adjustment marks with optical devices to obtain setting signals for the first position of the table, utilizing the setting signals to adjust the position of the first retaining plate and mask relative to the table to be in the focus plane of the optical devices, then shifting the table in a perpendicular direction to the direction of the particle beam to a second position, observing a second adjustment mark at the second position to obtain additional setting signals which serve for the adjustment of the mask into the focal plane of the optical devices.

Claim 11

A method for the alignment of a semiconductor wafer perpendicular to a direction of particle beams of an apparatus having means for mounting a semiconductor wafer including a retaining plate having means for fastening an object thereon, and two spaced optical means for controlling the movement of the retaining plate relative to a table, said two spaced optical means having focussing planes, the method having steps including securing a semiconductor wafer on the retaining plate by said means for fastening, observing first adjustment marks of the semiconductor wafer with the two optical means to create setting signals for changing the position of the retaining plate to position the wafer in the focus plane of the two optical devices, then shifting the table perpendicular to the direction of the particle beams to a second position, observing adjustment marks on the semiconductor wafer at said second position to obtain additional setting signals, utilizing the additional setting signals to make further adjustments in the position of the plane of the surface of the semiconductor wafer into the focus plane of said two optical means.

Claim 12

A method for the alignment of a semiconductor wafer perpendicular to a direction of particle beams of an apparatus having means for mounting a semiconductor wafer including a retaining plate having means for fastening an object thereon, and two spaced optical means for controlling the movement of the retaining plate relative to a table, said two spaced optical means having focussing planes, the method having steps including securing a semiconductor wafer on the retaining plate by said means for fastening, observing first adjustment marks of the semiconductor wafer with the two optical means to create setting signals for changing the position of the retaining plate to position the wafer in the focus plane of the two optical devices, then shifting the table perpendicular to the direction of the particle beams to a second position, observing adjustment marks on the semiconductor wafer at said second position to obtain additional setting signals, utilizing the additional setting signals to make further adjustments in the position of the plane of the surface of the semiconductor wafer into the focus plane of said two optical means.

Claim 13

A method for the alignment of a mask perpendicular to the direction of particle beams in an apparatus having first means including a first retaining plate for securing the mask, second means for securing a wafer on a second retaining plate positioned on a table, said method comprising the steps of securing the mask on a second retaining plate of the second means, observing first adjustment marks on the mask with optical devices to obtain setting signals for positioning the mask in the focal plane of said optical devices, moving the mask and second means to position the mask in the focal plane, then shifting the table in a perpendicular direction to present a second position, observing a second group of adjustment marks to create setting signals for the adjustment of the mask into the focal plane, positioning the mask in said focal plane utilizing the second set of signals, then contacting the mask with the first retaining plate of said first means, securing the mask to the first retaining plate while releasing the mask from the second retaining plate and then securing the first retaining plate in the fixed position.

Claim 14

A method for the alignment of a mask perpendicular to the direction of particle beams in an apparatus having first means including a first retaining plate for securing the mask, second means for securing a wafer on a second retaining plate positioned on a table, said method comprising the steps of securing the mask on a second retaining plate of the second means, observing first adjustment marks on the mask with optical devices to obtain setting signals for positioning the mask in the focal plane of said optical devices, moving the mask and second means to position the mask in the focal plane, then shifting the table in a perpendicular direction to present a second position, observing a second group of adjustment marks to create setting signals for the adjustment of the mask into the focal plane, positioning the mask in said focal plane utilizing the second set of signals, then contacting the mask with the first retaining plate of said first means, securing the mask to the first retaining plate while releasing the mask from the second retaining plate and then securing the first retaining plate in the fixed position.