Unit magnification projection system and method

A Dyson lens system, which comprises:

• a primary mirror having a substantially spherical concave mirror surface on one side thereof,
• a radiation source that passes radiation through an object plane,
• a lens group disposed on the same side as said mirror surface, and spaced from said mirror surface,
• means to direct said radiation from said source thereof to said lens group,
• said lens group and said mirror surface being so constructed that said radiation passes through said lens group to said mirror surface and is reflected back from said mirror surface through said lens group, and
• means to direct said reflected radiation from said lens group to an image plane,
• said means to direct radiation from said source to said lens group, and to direct reflected radiation from said lens group to an image plane, comprising a roof prism and a turning prism,
• said lens group including a first lens and a second lens,
• said second lens being between said first lens and said mirror surface, and being spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• said mirror surface and said lens group being constructed and arranged generally in Dyson relationship, and producing a substantially one-to-one image at said image plane.

A Dyson lens system, which comprise:

• a primary mirror having a substantially spherical concave mirror surface on one side thereof,
• a radiation source that passes radiation through an object plane,
• a lens group disposed on the same side as said mirror surface, and spaced from said mirror surface,
• means to direct said radiation from said source thereof to said lens group,
• said lens group and said mirror surface being so constructed that said radiation passes through said lens group to said mirror surface and is reflected back from said mirror surface through said lens group,
• means to direct said reflected radiation from said group to an image plane,
• said lens group including a first lens and a second lens,
• said second lens being between said first lens and said mirror surface, and being spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• said mirror surface and said lens group being constructed and arranged generally in Dyson relationship, and producing a substantially one-to-one image at said image plane, and
• a magnification adjustor to effect slight changes in the magnification ratio of the Dyson system,
• said magnification adjustor being between one of said means to direct and one of said image plane and said object plane.

A Dyson lens system, which comprises:

• a primary mirror having a substantially spherical concave mirror surface on one side thereof,
• a radiation source that passes radiation through an object plane,
• a lens group disposed on the same side as said mirror surface, and spaced from said mirror surface,
• means to direct said radiation from said source thereof to said lens group,
• said lens group and said mirror surface being so constructed that said radiation passes through said lens group to said mirror surface and is reflected back from said mirror surface through said lens group,
• means to direct said reflected radiation from said lens group to an image plane,
• said lens group including a first lens and a second lens,
• said second lens being between said first lens and said mirror surface, and being spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• said mirror surface and said lens group being constructed and arranged generally in Dyson relationship, and producing a substantially one-to-one image at said image plane,
• said first lens comprising a plano-convex lens element having its convex surface facing toward said mirror surface, and further comprising a concavo-convex lens element having its convex surface facing toward said mirror surface, said concavo-convex lens element being between said plano-convex lens element and said second lens, said first lens being a doublet.

A Dyson lens system, which comprises:

• a primary mirror having an aspherical concave mirror surface on one side thereof,
• a radiation source that passes radiation through an object plane,
• a lens group disposed on the same side as said mirror surface, and spaced from said mirror surface,
• means to direct said radiation from said source thereof to said lens group,
• said lens group and said mirror surface being so constructed that said radiation passes through said lens group to said mirror surface and is reflected back from said mirror surface through said lens group,
• means to direct said reflected radiation from said lens group to an image plane,
• said lens group including a first lens and a second lens,
• said second lens being between said first lens and said mirror surface, and being spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• said mirror surface and said lens group being constructed and arranged generally in Dyson relationship, and producing a substantially one-to-one image at said image plane,
• said first lens comprising being a plano-convex lens element having its convex surface facing toward said mirror surface, and further comprising a concavo-convex lens element having its convex surface facing toward said mirror surface, said concavo-convex lens element being between said plano-convex lens element and said second lens, said first lens being a doublet.

A Dyson lens system, which comprises:

• a primary mirror having an aspherical concave mirror surface on one side thereof,
• a radiation source that passes radiation through an object plane,
• a lens group disposed on the same side as said mirror surface, and spaced from said mirror surface,
• means to direct said radiation from said source thereof to said lens group,
• said lens group and said mirror surface being so constructed that said radiation passes through said lens group to said mirror surface and is reflected back from said mirror surface through said lens group,
• means to direct said reflected radiation from said lens group to an image plane,
• said lens group including a first lens and a second lens,
• said second lens being between said first lens and said mirror surface, and being spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• said mirror surface and said lens group being constructed and arranged generally in Dyson relationship, and producing a substantially one-to-one image at said image plane,
• said first lens comprising a plano-convex lens element having its convex surface facing toward said mirror surface, and further comprising a concavo-convex lens element having its convex surface facing toward said mirror surface, said concavo-convex lens element being between said plano-convex lens element and said second lens, said first lens being a doublet
• said second lens being a thick meniscus lens.

A Dyson lens system, comprising:

• a primary mirror having a concave mirror surface,
• a plano-convex lens spaced a large distance from said mirror surface,
• said plano-convex lens having its convex surface facing said mirror surface and having the same optical axis as said mirror surface,
• a concavo-convex lens element having its convex surface facing said mirror surface,
• said concavo-convex lens having said optical axis and being between said plano-convex lens and said mirror surface,
• a meniscus lens having said optical axis and being disposed between said concavo-convex lens and said mirror surface,
• said meniscus lens being spaced from said concavo-convex lens a large part of the distance from said concavo-convex lens to said mirror surface,
• the convex surface of said meniscus lens facing said mirror surface,
• a light source,
• a first prism to direct light from said source through said lenses from which it passes to said mirror surface,
• said light reflecting from said mirror surface and passing back through said lenses, and
• a second prism to direct to an image plane said light that reflects from said mirror surface and passes back through said lenses.

A Dyson lens system, comprising:

• a primary mirror having a concave mirror surface,
• a plano-convex lens spaced a large distance from said mirror surface,
• said plano-convex lens having its convex surface facing said mirror surface and having the same optical axis as said mirror surface,
• a concavo-convex lens having its convex surface facing said mirror surface,
• said concavo-convex lens having said optical axis and being between said plano-convex lens and said mirror surface,
• a meniscus lens having said optical axis and being disposed between said concavo-convex lens and said mirror surface,
• said meniscus lens being spaced from said plano-convex lens a large part of the distance from said plano-convex lens to said mirror surface, the convex surface of said meniscus lens facing said mirror surface,
• a light source,
• a first prism to direct light from said source through said lenses from which it passes to said mirror surface,
• said light reflecting from said mirror surface and passing back through said lenses,
• there being an object plane disposed between said light source and said first prism,
• a second prism to direct to an image plane said light that reflects from said mirror surface and passes back through said lenses, and
• a magnification compensator disposed between said prisms and one of said object plane and said image plane.

A Dyson lens system, comprising:

• a primary mirror having a concave mirror surface,
• a plano-convex lens spaced a large distance from said mirror surface,
• said plano-convex lens having its convex surface facing said mirror surface and having the same optical axis as said mirror surface,
• a concavo-convex lens having its convex surface facing said mirror surface,
• said concavo-convex lens having said optical axis and being between said plano-convex lens and said mirror surface,
• a meniscus lens having said optical axis and being disposed between said concavo-convex lens and said mirror surface,
• said meniscus lens being spaced from said plano-convex lens a large part of the distance from said plano-convex lens to said mirror surface, the convex surface of said meniscus lens facing said mirror surface,
• a light source,
• a first prism to direct light from said source through said lenses from which it passes to said mirror surface,
• said light reflecting from said mirror surface and passing back through said lenses, and
• a second prism to direct to an image plane said light that reflects from said mirror surface and passes back through said lenses,
• one of said first and second prisms being a roof prism, the other of said first and second prisms being a turning prism.

A Dyson lens system, comprising:

• a primary mirror having a concave mirror surface,
• said concave mirror surface being slightly aspherical,
• a plano-convex lens element spaced a large distance from said mirror surface,
• said plano-convex lens element having its convex surface facing said mirror surface and having the same optical a axis as said mirror surface,
• a concavo-convex lens element having its convex surface facing said mirror surface,
• said concavo-convex lens element having said optical axis and being between said plano-convex lens element and said mirror surface,
• a meniscus lens having said optical axis and being disposed between said concavo-convex lens element and said mirror surface,
• said meniscus lens being spaced a large part of the distance from said plano-convex lens element to said mirror surface, the convex surface of said meniscus lens facing said mirror surface,
• a light source,
• a first prism to direct light from said source through said lenses from which it passes to said mirror surface,
• said light reflecting from said mirror surface and passing back through said lenses, and
• a second prism to direct to an image plane said light that reflects from said mirror surface and passes back through said lenses,
• said plano-convex lens element and said concavo-convex lens element being a doublet and being formed of different glass types.

A Dyson lens system, which comprises:

• a first prism and a second prism mounted adjacent each other,
• a primary mirror spaced from said prisms and having a substantially spherical mirror surface facing said prisms,
• said first prism being oriented to direct light from a light source toward said mirror surface,
• said second prism being oriented to receive light from said mirror surface and to direct said received light toward an image plane,
• lens disposed between said prisms and said mirror surface and having the same optical axis as said mirror surface,
• said lens cooperating with said first and second prisms in transmitting said light to said mirror surface and then from said mirror surface toward said image plane,
• said first prism being a roof prism and said second prism being a turning prism, said prisms and said mirror surface cooperating with each other in orienting an image at said image plane, to cause such image to be oriented the same as the object at the object plane, and
• a magnification adjustor disposed adjacent said prisms to change slightly the magnification of the system.

A substantially one-to-one imaging method, which comprises:

• providing a concave mirror surface and a first lens in Dyson relationship to each other;
• providing an additional lens between said first lens and said mirror surface and spaced from said first lens a large part of the distance from said first lens to said mirror surface,
• directing radiation through said first lens and said additional lens to said mirror surface, so that said radiation reflects back from said mirror surface through said additional lens and said first lens,
• performing said steps in Dyson manner so that the magnification ratio is substantially one-to-one, and
• directing said reflected radiation from said first lens to an image plane in such manner that the image is not inverted, and without causing said reflected radiation to pass through any additional lenses that are related to each other in Dyson manner.

A method of providing unit imaging but with controlled slight variation in magnification in order to compensate for variations in substrate sizes that occur during microelectronics manufacture, said method comprising:

• providing a primary mirror having a substantially
• spherical concave surface, directing light toward said mirror surface through three lenses each having a different glass type adapted to minimize chromatic and other aberrations, employing optical elements including a prism to direct to an image plane light that reflects from said mirror surface and passes back through said three lenses,
• providing a large air gap between said image plane and said optical elements including a prism,
• providing an image-size adjustor in said air gap, and operating said image-size adjustor to change slightly the size of the image to different values close to one-to-one.

A Dyson lens system, which comprise:

• a radiation source to pass radiation through an object plane,
• a primary mirror having a concave surface,
• lens disposed to pass radiation to said primary mirror and also to receive reflected radiation from said primary mirror,
• transmitting means to transmit radiation from said radiation source to said lens means, and to transmit reflected radiation from said lens to an image plane, and
• adjustment means to effect very small and accurate adjustments in said transmitting means in order to change slightly the location of the image transmitted to said image plane,
• said transmitting means comprising two individually-mounted turning elements for directing radiation around corner from said source into said lens and for directing said radiation around a corner from said lens means to said image plane,
• said adjustment means comprising means to adjust slightly and individually the position of at least one of said individually-mounted turning elements,
• said mirror and lens being so constructed and oriented that the magnification ratio is substantially one-to-one,
• said turning elements comprising at least no prism.

A Dyson lens system, which comprises:

• a radiation source to pass radiation through an object plane,
• a primary mirror having a concave surface,
• lens disposed to pass radiation to said primary mirror and also to receive reflected radiation from said primary mirror,
• transmitting means to transmit radiation from said radiation source to said lens, and to transmit reflected radiation from said lens means to an image plane, and
• adjustment means to effect very small and accurate adjustments in said transmitting means in order to change slightly the location of the image transmitted to said image plane,
• said transmitting means comprising two individually-mounted turning elements for directing radiation around a corner from
• said source into said lens means and for directing said radiation around a corner from said lens means to said image plane,
• said adjustment means comprising means to adjust slightly and individually the position of at least one of said individually-mounted turning elements,
• said mirror and lens being so constructed and oriented that the magnification ratio is substantially one-to-one,
• said turning elements comprising a roof prism and a turning prism.

A method of providing unit imaging in a Dyson system, but with controlled slight variation in magnification in order to compensate for variations in substrate sizes that occur during microelectronics manufacture, said method comprising:

• providing a Dyson system including a primary mirror and a lens in Dyson relationship to each other,
• directing light through said lens toward said mirror,
• employing optical elements including a prism to direct to an image plane light that reflects from said mirror and passes back through said lens,
• providing a large air gap between said image plane and said optical elements including a prism,
• providing an image-size adjustor in said air gap, and operating said image-size adjustor to change slightly the size of the image to different values close to one-to-one.

A compensating Dyson lens system, comprising:

• a primary mirror having a concave mirror surface,
• a lens spaced from said mirror surface,
• said mirror and lens being constructed and oriented to cooperate with each other in Dyson relationship,
• said mirror and lens being disposed between spaced-apart object and image planes that are parallel to each other,
• a first prism and a second prism disposed between said object and image planes, and being located on the side of said lens that is remote from said mirror,
• a radiation source located on the side of said object plane remote from said prisms,
• said radiation source being adapted to direct radiation through said object plane to one of said prisms, from which said radiation passes through said lens to said mirror and back through said lens and the other of said prisms to said image plane,
• a large air gap provided between one of said prisms and the one of said planes that is nearest thereto, and
• a magnification adjustor disposed in said air gap,
• said magnification adjustor being adapted to be operated to change slightly the magnification of the system so as to compensate for slight variations in the size of a workpiece disposed in said image plane.

A method of achieving substantially perfect positioning of an image in the image plane of a projection scanning microlithography apparatus in which the scans are parallel to each other and partially overlap each other, so that there is no twist causing points at the image plane to be out of superposed conditions during adjacent partially-overlapping scans, which method comprises:

• providing a test film in the image plane of a projection scanning microlithography apparatus having an optical projection system that is one-to-one and incorporates beam-turning elements, and in which the object and image have the same orientation,
• providing at least a point in the object plane of said apparatus,
• passing the field of said system through said point and through said optical projection system onto said film,
• relatively moving said optical projection system on the one hand, and said point and said film on the other hand, to a position such that:
• (a) the moved field only partially overlaps the above-mentioned field, and
• (b) the resulting projected point would under conditions of high accuracy be superposed on the point resulting from the field stated above, and
• physically adjusting the position of at least one of said turning elements until said "two" points are superposed.

In combination with a projection-scanning microlithography apparatus of the type in which the scans are parallel to each other and partially overlap each other, and in which the object and image planes are parallel to each other and spaced from each other, an adjustable optical system for projecting a twist-free one-to-one image from a mask in said object plane to a substrate in said image plane with the object and image having the same orientation, said adjustable optical system comprising:

• a concave primary mirror,
• first turning means to receive radiation passed through the object plane and turn said radiation for transmission to said mirror,
• second turning means to receive said radiation from said primary mirror and turn said radiation for transmission to the image plane,
• first mounting means to mount said first turning means,
• second mounting means to mount said second turning means separately and independently from said first mounting means and from said first turning means,
• first adjustment means to effect slight individual adjustments of the position of said first turning means, to thereby slightly adjust the position of the image at said image plane, and
• second adjustment means to effect slight individual adjustment of the position of said second turning means, to thereby slightly adjust the position of the image at said image plane.