CN102645853B - Diffractive annular illumination generator and method for manufacturing same - Google Patents

Abstract

Disclosed are a diffractive annular illumination generator used for an off-axis illuminating system of an ultraviolet lithography machine and a method for manufacturing the diffractive annular illumination generator. The diffractive annular illumination generator is characterized by comprising a first diffractive element and a second diffractive element, the surface of the first diffractive element and the surface of the second diffractive element are perpendicular to an optical axis, the first diffractive element transforms a parallel light beam into an annular divergent light beam, an included angle theta is formed between a divergent light beam generated by the annular light beam and the optical axis, and the second diffractive element transforms the annular divergent light beam into an annular parallel light beam. The light intensity distribution size of a pupil plane can be continuously adjusted, the diffractive annular illumination generator and the method have the advantages of simple structure and mature processing technology, and production cost of a lithography machine can be effectively reduced.

Description

Diffraction type ring illumination generator and preparation method thereof

Technical field

The present invention relates to lithographic equipment, particularly a kind of diffraction type ring illumination generator of regulating continuously pupil plane light distribution size for ultraviolet photolithographic machine off-axis illumination system and preparation method thereof.

Background technology

In the illuminator of advanced litho machine, need to strengthen the resolution of etching system according to structure and the suitable pupil plane illumination light intensity distributed dimension of size Selection of mask figure, increasing depth of focus, and improve image contrast, thus improve photoetching quality.

The conciliation of pupil plane light distribution size at present adopts the conical mirror group consisted of two refraction conical mirrors of concave, convex to realize.Two conical mirrors are arranged along the direction of optical axis, and place perpendicular to optical axis, realize the continuous adjusting of light intensity distributed dimension on pupil plane by changing distance between two conical mirrors.The shortcoming of this method is that more difficult the completing of processing, the particularly processing of concave surface conical mirror of refraction conical mirror all also is difficult to realize both at home and abroad.Reason is that the processing of conical mirror need to complete by grinding with glossing, the processing of concave surface conical mirror central area is difficult point always, the material that the ultraviolet photolithographic system can be utilized in addition is limited, the fused quartz price is lower, but be difficult to accurate face type processing, the hardness of calcium fluoride material is higher, favourable to processing, but price is very expensive, be unfavorable for the reduction of photoetching complete machine cost.

Formerly, in technology " ring-shaped light spot conversion mirror " (referring to patent CN 2163387Y), disclose a kind of ring-shaped light spot and transformed mirror, utilized the refraction conical mirror to produce annular hot spot.For surface figure accuracy, less demanding Laser Processing can meet the demands the method, but is subject to processing the restriction of technique, more difficult being transplanted in lithographic equipment.

Summary of the invention

The object of the invention is to overcome the deficiency of above-mentioned formerly technology, a kind of generator of the diffraction type ring illumination for ultraviolet photolithographic machine off-axis illumination system and preparation method thereof is provided, this diffraction type ring illumination generator substitutes traditional refraction conical mirror group, can regulate continuously pupil plane light distribution size, and simple in structure, the characteristics of processing technology maturation, can effectively reduce the production cost of litho machine.Be applicable to the diffraction type ring illumination generator of any ultraviolet light wave band.

Technical solution of the present invention is as follows:

A kind of diffraction type ring illumination generator, characteristics are that its formation comprises that Surface Vertical is in the first diffraction element and second diffraction element of optical axis, the first diffraction element is transformed into parallel beam the divergent beams that become a generation with optical axis become angle theta annular divergent beams with optical axis, the second diffraction element is transformed into the annular parallel beam by the annular divergent beams, realize that by the distance of regulating between two diffraction elements the continuous adjusting of output beam size, the ultimate range between the first diffraction element and the second diffraction element are that d is determined by following formula;

${\mathrm{\φ}}_{\mathrm{out}}-{\mathrm{\φ}}_{\mathrm{in}}=2d\sin \mathrm{\θ}\·\left[\frac{\cos {\mathrm{\θ}}_1}{\cos (\mathrm{\θ}+{\mathrm{\θ}}_1)}\right]$

Wherein: θ ₁for intermediate parameters, meet equation: sin (θ+θ ₁)/sin (θ ₁)=n, the Refractive Index of Material that n is the first diffraction element and the second diffraction element under the illuminating bundle wavelength X,

for the bore of incident beam,

for the external diameter of annular outgoing beam, the selection range of angle theta is 10 °～60 °;

Described the first diffraction element and the second diffraction element form by regularly arranged rectangular cells, and the transmitance of each unit is identical, only has certain phasic difference, and described the first diffraction element is that the length of side is D ₁square transparent panel, the initial point of rectangular coordinate is positioned at the center of the first diffraction element, the plane of incidence is plane, exit facet has position and distributes mutually, its phase distribution matrix is

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₁/ 2 to D ₁be divided into 2 in/2 scope ⁿindividual, N is integer, usually chooses 10 to 12, and D ₁/ 2 ⁿat least be greater than 1 μ m,, mod{} means right

divided by 2 π remainder numbers;

Described the second diffraction element is that the length of side is D ₂square transparent panel, the initial point of rectangular coordinate system is positioned at the center of the second diffraction element, the plane of incidence has its position and distributes mutually, exit facet is plane, its phase distribution matrix is

${\mathrm{\&phi;}}_2(x,y)=\mathrm{mod}\left\{\right[-\sqrt{x^2+{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000157470020000012.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}\&CenterDot;\tan \left({\mathrm{\&theta;}}_1\right)]\&CenterDot;(n-1)/\mathrm{\&lambda;},2\mathrm{\&pi;}\};$

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₂/ 2 to D ₂be divided into 2 in/2 scope ⁿindividual, N is integer, and mod{} means right

divided by 2 π remainder numbers.

Described illuminating bundle wavelength X comprises 365nm, 248nm, 193nm, even shorter wavelength.

The preparation method of described diffraction type ring illumination generator, its characteristics are that the method comprises the following steps:

1. comprise the bore of illuminating bundle wavelength X, incident beam according to the actual conditions of litho machine

maximum outgoing beam external diameter

the refractive index n of the base material of selected the first diffraction element and the second diffraction element; Determine the divergent beams of the first diffraction element generation and the angle theta of optical axis, the selection range of angle theta is pressed sin (θ+θ after being 10 °～60 ° selected angle theta ₁)/sin (θ ₁)=n is calculated as intermediate parameters θ ₁;

2. calculate the ultimate range d between the first diffraction element and the second diffraction element by following formula:

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right];$

3. calculate the position phase distribution matrix of described the first diffraction element by following formula

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, θ ₁be the intermediate parameters that 1. step tries to achieve, mod{} means right

divided by 2 π remainder numbers;

4. determine the position phase distribution matrix of described the second diffraction element by following formula

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, and mod{} means right

divided by 2 π remainder numbers;

5. adopt existing ripe lithography process technique preparation to there is the first diffraction element and the second diffraction element that described position distributes mutually;

6. assemble described diffraction type ring illumination generator.

With technology formerly, compare, the present invention has following technological merit:

(1) the present invention adopts diffraction optics method to realize the ring illumination generator, very thin thickness due to diffraction element, be conducive to reduce litho machine complete machine size, can effectively avoid the constructive interference of traditional conical mirror group with other litho machine parts, simplified corresponding structure simultaneously.

(2) the first diffraction element of the present invention and the second diffraction element can utilize existing photoetching process to be processed, have the advantages that processing is ripe, machining precision easily guarantees, in addition, realize the processing of diffraction type ring illumination generator on can the fused quartz material lower in price, effectively reduce the manufacturing cost of litho machine.

The accompanying drawing explanation

Fig. 1 is the fundamental diagram of diffraction type ring illumination generator of the present invention.

Fig. 2 is the schematic diagram of diffraction type ring illumination generator of the present invention.

Fig. 3 is the simulation result of one embodiment of the invention.

Embodiment

Below in conjunction with accompanying drawing and example, the present invention is further illustrated, but should not limit the scope of the invention with this.

First refer to Fig. 1, Fig. 1 is the fundamental diagram of diffraction type ring illumination generator of the present invention, for generation of ring illumination pupil required in the ultraviolet photolithographic machine, distributes.As seen from the figure, diffraction type ring illumination generator of the present invention, comprise that Surface Vertical is in the first diffraction element 102 and second diffraction element 103 of optical axis, the first diffraction element 102 is transformed into parallel beam the divergent beams that become a generation with optical axis become angle theta annular divergent beams with optical axis, the second diffraction element 103 is transformed into the annular parallel beam by the annular divergent beams, realize the continuous adjusting of output beam size by the distance of regulating between two diffraction elements, ultimate range between the first diffraction element 102 and the second diffraction element 103 is that d is determined by following formula,

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right]$

Wherein: θ ₁for intermediate parameters, meet equation: sin (θ+θ ₁)/sin (θ ₁)=n, the Refractive Index of Material that n is the first diffraction element 102 and the second diffraction element 103 under the illuminating bundle wavelength X,

for the bore of incident beam, for the external diameter of annular outgoing beam, the angle theta selection range is 10 °～60 °;

Described the first diffraction element 102 and the second diffraction element 103 form by regularly arranged rectangular cells, and the transmitance of each unit is identical, only has certain phasic difference, and described the first diffraction element 102 is that the length of side is D ₁square transparent panel, the initial point of rectangular coordinate is positioned at the first diffraction element 102 center, the plane of incidence is plane, exit facet has position and distributes mutually, its phase distribution matrix is

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₁/ 2 to D ₁be divided into 2 in/2 scope ⁿindividual, N is integer, usually chooses 10 to 12, and D ₁/ 2 ⁿat least be greater than 1 μ m,, mod{} means right

divided by 2 π remainder numbers;

Described the second diffraction element 103 is that the length of side is D ₂square transparent panel, the initial point of rectangular coordinate system is positioned at the second diffraction element 103 center, the plane of incidence has its position and distributes mutually, exit facet is plane, its phase distribution matrix is

${\mathrm{\&phi;}}_2(x,y)=\mathrm{mod}\left\{\right[-\sqrt{x^2+{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000157470020000012.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}\&CenterDot;\tan \left({\mathrm{\&theta;}}_1\right)]\&CenterDot;(n-1)/\mathrm{\&lambda;},2\mathrm{\&pi;}\};$

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₂/ 2 to D ₂be divided into 2 in/2 scope ⁿindividual, N is integer, and mod{} means right divided by 2 π remainder numbers.

The first diffraction element 102 and the second diffraction element 103, place the center of two diffraction elements and optical axis coincidence perpendicular to optical axis.Incident beam is circular illumination light field 101, after the first diffraction element 102 and the second diffraction element 103, obtains annular illumination light field 105 in output face 104.The one side of the first diffraction element 102 is plane, and another side contains position and distributes mutually, and for example it distributes surface structure figure mutually as shown in 106 in figure.The one side of the second diffraction element 103 is plane, and another side contains position and distributes mutually, and for example position distributes surface structure figure mutually as shown in 107 in figure.During the work of diffraction type ring illumination generator, by regulating the distance between the first diffraction element 102 and the second diffraction element 103, maximum is no more than d, realizes the continuous adjusting of ultraviolet photolithographic machine off-axis illumination system pupil plane light distribution size.

Fig. 2 is the schematic diagram of diffraction type ring illumination generator of the present invention.Phantom line segments AE in figure is equivalent to the first diffraction element 102, its function is that parallel beam is transformed into to the annular divergent beams that become a special angle with optical axis, phantom line segments BC in figure is equivalent to the second diffraction element 103, and its function is that annular divergent beams are transformed into to annular parallel beam.

Bore

for light beam after the first diffraction element 102, annular divergent beams that to produce with optical axis included angle be θ, then, after the second diffraction element 103, be transformed into annular parallel beam, its external diameter is

in figure, line segment AE is parallel with BC, and and the angle of line segment BD be θ ₁, line segment BD is perpendicular to optical axis.According to the plane geometry principle, we can obtain following relation:

BC＝BD/cosθ ₁；

BC/AC＝sinθ/sin(90°-θ-θ ₁)；

The length that wherein BC is line segment BC, the length that BD is line segment BD, and

the length that AC is line segment AC, and AC=d.By these two relational expressions, we can obtain:

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right]---\left(1\right)$

In addition, according to the refraction law of geometrical optics, can obtain:

sin(θ+θ ₁)/sin(θ ₁)＝n； (2)

In conjunction with above-mentioned two relational expressions, we have just set up the angle theta of divergent beams and optical axis and the relation of the ultimate range d between the first diffraction element (102) and the second diffraction element (103), the source of two formula of Here it is this patent diffraction type ring illumination generator.

Secondly, follow the ultimate principle of geometrical optics deflecting light beams direction [referring to strongly fragrant road silver peace talk permanent English according to the direction of diffraction optics principal maximum diffracted beam, engineering optics, China Machine Press, 1999, the 247-251 page], build the position phase distribution matrix of the first diffraction element 102 and the second diffraction element 103.Regard line segment AE and the upper every some coordinate at optical axis direction of CF as equivalence position phase, respectively they are carried out to the discretize processing, and be normalized in 0～2 π, thereby obtain the position phase distribution matrix of the first diffraction element 102 and the second diffraction element 103.Concrete computing formula is as follows: the position phase distribution matrix of the first diffraction element 102 is

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₁/ 2 to D ₁be divided into 2 in/2 scope ⁿindividual, N is integer, usually chooses 10 to 12, and D ₁/ 2 ⁿat least be greater than 1 μ m,, mod{} means right

divided by 2 π remainder numbers;

The position phase distribution matrix of described the second diffraction element 103 is

${\mathrm{\&phi;}}_2(x,y)=\mathrm{mod}\left\{\right[-\sqrt{x^2+{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000157470020000012.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}\&CenterDot;\tan \left({\mathrm{\&theta;}}_1\right)]\&CenterDot;(n-1)/\mathrm{\&lambda;},2\mathrm{\&pi;}\}---\left(4\right)$

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₂/ 2 to D ₂be divided into 2 in/2 scope ⁿindividual, N is integer, and mod{} means right

divided by 2 π remainder numbers.

Below by a specific embodiment, further illustrate the structure of the diffraction type ring illumination generator of using in the ultraviolet photolithographic illuminator.At first determine following parameter: ultraviolet light beam wavelength X=248nm, fused quartz Refractive Index of Material n=1.5 under this wavelength, the bore of incident beam 101:

maximum outgoing beam 105 external diameters

then according to following steps design diffraction type ring illumination generator 102 and 103:

1. determine the divergent beams and the angle theta of optical axis and the ultimate range d between the first diffraction element 102 and the second diffraction element 103 that are produced by the first diffraction element 102

Both relations can be meaned by following system of equations:

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right];$

sin(θ+θ ₁)/sin(θ ₁)＝n；

Wherein, θ ₁for intermediate parameters.By above-mentioned system of equations, and the angle theta of choosing suitable divergent beams and optical axis according to actual structural limitations and processing conditions, the ultimate range d between the first diffraction element (102) and the second diffraction element (103), and intermediate parameters θ ₁.Here choosing θ is 18.59 °, θ ₁being 30 °, is 24mm apart from d accordingly.

2. determine the position phase distribution matrix of described the first diffraction element 102

the first diffraction element is selected square structure, its bore D ₁d ₁should be slightly larger than the bore of incident beam

the present embodiment is elected 21mm x 21mm as.Its position distributes and can be expressed as a two-dimensional matrix mutually, and can try to achieve by following formula:

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, θ ₁be the intermediate parameters that 1. step tries to achieve, mod{} means right

divided by 2 π remainder numbers.Choosing of x and y coordinate is to be divided into 2 at-10.5mm in the scope of 10.5mm ⁿindividual, the present embodiment N gets 11, D/2 ⁿ=10.25 μ m, be greater than 1 μ m.The x that substitution is different and y coordinate can obtain a two-dimensional matrix, and this matrix is exactly the position phase distribution matrix of the first diffraction element (102)

3. determine the position phase distribution matrix of described the second diffraction element 103

The second diffraction element is selected square structure, its bore D ₂d ₂should be slightly larger than the external diameter of outgoing beam

the present embodiment is elected 42mm x 42mm as.Its position distributes and can be expressed as a two-dimensional matrix mutually, and can try to achieve by following formula:

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, θ ₁be the intermediate parameters that 1. step tries to achieve, mod{} means right

divided by 2 π remainder numbers.M is a constant, because the position of calculating distributes mutually, is relative, so the M here can be taken as zero.Choosing of x and y coordinate is to be divided into 2 at-21mm in the scope of 21mm ⁿindividual, identical in 3. of N value and described step.The x that substitution is different and y coordinate can obtain a two-dimensional matrix, and this matrix is exactly the position phase distribution matrix of the second diffraction element 103

4. designed

By obtaining the position phase distribution matrix of described the first diffraction element 102 and the second diffraction element 103

with

and ultimate range d, just completed required design.During work, by regulating the distance between described the first diffraction element 102 and the second diffraction element 103, maximum is no more than d, realizes the continuous adjusting of ultraviolet photolithographic machine off-axis illumination system pupil plane light distribution size.

The simulation result that has shown the present embodiment in Fig. 3, emulation is based on fresnel diffraction theory [referring to the permanent English of strongly fragrant road silver peace talk, engineering optics, China Machine Press, 1999,247-251 page].The 301st, the surface of intensity distribution of incident beam, the gray scale of figure represents light intensity, incident beam is circular light distribution.When the distance of the first diffraction element 102 and the second diffraction element 103 is 8mm, obtain annular light distribution 302 in output face, when distance is 16mm, obtain annular light distribution 303 in output face, when distance is 24mm, obtain annular light distribution 304 in output face.Therefrom can find, change along with distance between the first diffraction element 102 and the second diffraction element 103, in output face, the external diameter of annular illumination light field is in continuous expansion, and the endless belt width of ring illumination field does not change with the variation of distance between the first diffraction element 102 and the second diffraction element 103, remain the radius value of the circular light field of incident.Above-mentioned 2 these diffraction element groups of proof have realized the function of ring illumination generator.

With technology formerly, compare, the present invention has following technological merit:

(1) the present invention adopts the method for diffraction optics to realize the ring illumination generator, very thin thickness due to diffraction element, be conducive to reduce litho machine complete machine size, can effectively avoid the constructive interference of traditional conical mirror group with other litho machine parts, simplify corresponding structural design simultaneously.

(2) the diffraction element group of the present invention's design utilizes existing photoetching process to realize, have the advantages that processing is ripe, machining precision easily guarantees, in addition, realize the processing of diffraction type ring illumination generator on can the fused quartz material lower in price, effectively reduce the manufacturing cost of litho machine.

Claims (3)

1. a diffraction type ring illumination generator, be characterised in that its formation comprises that Surface Vertical is in the first diffraction element (102) and second diffraction element (103) of optical axis, the first diffraction element (102) is transformed into parallel beam the divergent beams that become a generation with optical axis become angle theta annular divergent beams with optical axis, the second diffraction element (103) is transformed into the annular parallel beam by the annular divergent beams, realize the continuous adjusting of output beam size by the distance of regulating between two diffraction elements, ultimate range between the first diffraction element (102) and the second diffraction element (103) is that d is determined by following formula,

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right]$

Wherein: θ ₁for intermediate parameters, meet equation: sin (θ+θ ₁)/sin (θ ₁)=n, the Refractive Index of Material that n is the first diffraction element (102) and the second diffraction element (103) under the illuminating bundle wavelength X,

for the bore of incident beam,

for the external diameter of annular outgoing beam, the selection range of angle theta is 10 °～60 °;

Described the first diffraction element (102) and the second diffraction element (103) form by regularly arranged rectangular cells, and the transmitance of each unit is identical, only has certain phasic difference, and described the first diffraction element (102) is that the length of side is D ₁square transparent panel, the initial point of rectangular coordinate is positioned at the center of the first diffraction element (102), the plane of incidence is plane, exit facet has position and distributes mutually, its phase distribution matrix is

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₁/ 2 to D ₁be divided into 2 in/2 scope ⁿindividual, N is integer, usually chooses 10 to 12, and D ₁/ 2 ⁿat least be greater than 1 μ m,, mod{} means right

divided by 2 π remainder numbers;

Described the second diffraction element (103) is that the length of side is D ₂square transparent panel, the initial point of rectangular coordinate system is positioned at the center of the second diffraction element (103), the plane of incidence has position and distributes mutually, exit facet is plane, its phase distribution matrix is

${\mathrm{\&phi;}}_2(x,y)=\mathrm{mod}\left\{\right[-\sqrt{x^2+y^2}\&CenterDot;\tan \left({\mathrm{\&theta;}}_1\right)]\&CenterDot;(n-1)/\mathrm{\&lambda;},2\mathrm{\&pi;}\};$

Wherein: x and y mean rectangular coordinate, and choosing of x and y coordinate is at-D ₂/ 2 to D ₂be divided into 2 in/2 scope ⁿindividual, N is integer, and mod{} means right

divided by 2 π remainder numbers.

2. diffraction type ring illumination generator according to claim 1, is characterized in that described illuminating bundle wavelength X comprises 365nm, 248nm, 193nm, even shorter wavelength.

3. a method for preparing diffraction type ring illumination generator claimed in claim 1, is characterized in that the method comprises the following steps:

1. comprise the bore of illuminating bundle wavelength X, incident beam according to the actual conditions of litho machine

maximum outgoing beam external diameter the refractive index n of the base material of selected the first diffraction element and the second diffraction element; Determine the divergent beams of the first diffraction element (102) generation and the angle theta of optical axis, the selection range of angle theta is pressed sin (θ+θ after being 10 °～60 ° selected angle theta ₁)/sin (θ ₁)=n is calculated as intermediate parameters θ ₁;

2. calculate the ultimate range d between the first diffraction element (102) and the second diffraction element (103) by following formula:

${\mathrm{\&phi;}}_{\mathrm{out}}-{\mathrm{\&phi;}}_{\mathrm{in}}=2d\sin \mathrm{\&theta;}\&CenterDot;\left[\frac{\cos {\mathrm{\&theta;}}_1}{\cos (\mathrm{\&theta;}+{\mathrm{\&theta;}}_1)}\right];$

3. calculate the position phase distribution matrix of described the first diffraction element (102) by following formula

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, θ ₁be the intermediate parameters that 1. step tries to achieve, mod{} means right divided by 2 π remainder numbers;

4. determine the position phase distribution matrix of described the second diffraction element (103) by following formula

Wherein, x and y mean rectangular coordinate, and n is the refractive index of material, and θ 1 is the intermediate parameters that 1. step tries to achieve, and mod{} means right

divided by 2 π remainder numbers.M is a constant, because the position of calculating distributes mutually, is relative, so the M here can be taken as zero;

5. adopt existing ripe lithography process technique preparation to there is the first diffraction element (102) and the second diffraction element (103) that described position distributes mutually;

6. assemble described diffraction type ring illumination generator.

Images