CN102629082B - Design method of extreme ultra-violet lithography compound eye lighting system - Google Patents

Abstract

The invention provides a design method of an extreme ultra-violet lithography compound eye lighting system, which includes the detailed steps: determining a distance of an exit pupil of a lighting system according to parameters of an appointed projection objective lens; determining a coordinate system and obtaining coordinates of each device; determining coordinates of a center of the exit pupil according to coordinates of the distance of the exit pupil and the center of a mask; enabling the center of the exit pupil to coincide with an adjacent focus of a grazing incidence lens and calculating curve radius of the grazing incidence lens; enabling a non-adjacent focus of a first relay lens to coincide with an adjacent focus of the grazing incidence lens and calculating the curve radius of the first relay lens; enabling an adjacent focus of a second relay lens to coincide with an adjacent lens of the first relay lens and calculating the curve radius of the second relay lens; enabling a non-adjacent focus of a condenser to be a convergence point of emergent light of a homogenization system, and determining arrangement of compound eye elements on a diaphragm compound eye flat and a view field compound eye flat in the homogenization system according to the convergence point. The design method can be applied to different projection objective lenses.

Description

A kind of method for designing of extreme ultraviolet photolithographic fly-eye illumination system

Technical field

The invention provides a kind of method for designing of extreme ultraviolet photolithographic fly-eye illumination system, belong to the photoetching lighting technical field.

Background technology

Current large scale integrated circuit generally adopts etching system manufacturing.Etching system mainly is divided into: four parts such as illuminator, mask, optical projection system and wafer.The light that light source sends is incident to mask after focusing on through condenser; Through after mask, light is incident on the wafer that scribbles photoresist via optical projection system, so just mask pattern is replicated on wafer.

Extreme ultraviolet photolithographic EUVL is that the extreme ultraviolet EUV ray take wavelength as 11～14nm is the microelectronics photoetching technique of exposure light source, is applicable to characteristic dimension and is 32nm and the more production in enormous quantities of the wide integrated circuit of fine rule.The core component of projection aligner is the projection exposure optical system, and the most important ingredient of this system is illuminator and projection objective system.The illuminator major function is Uniform Illumination to be provided, to control exposure dose and to realize the off-axis illumination pattern for the mask face.Illuminator as the litho machine important component part is most important to improving whole litho machine performance, and therefore designing illuminator is to complete the important step of whole projection exposure system therefor.

The design philosophy of extreme ultraviolet photolithographic illuminator mainly contains at present: double compound eye illumination, the Lighting Design of corrugated plate illumination and free form surface etc., wherein double compound eye illumination is good with its even light effect, process technology is more ripe, be convenient to control, and be easy to realize that the advantage such as off-axis illumination becomes the main flow project organization of extreme ultraviolet photolithographic illuminator.

Disclose at present the structure of part extreme ultraviolet photolithographic fly-eye illumination system abroad, comprised successively according to the direction of beam propagation: light source, condenser, even photosystem (comprise diaphragm compound eye dull and stereotyped and visual field compound eye flat board), relay lens group (comprising the first relay lens and the second relay lens) and glancing incidence mirror; Wherein even photosystem is double compound eye, and condenser, relay lens group and glancing incidence mirror etc. is quadric surface, and the relay lens group is ellipsoid, and plunderring into mirror is hyperboloid.The parameter of every suit fly-eye illumination system be all lighting requirement according to the photoetching projection objective lens that is complementary with it and definite, in case the lighting requirement of projection objective changes, in illuminator, the parameter of each optical element may change.Therefore, be necessary to work out a kind of method, can faster, more accurate foundation have the fly-eye illumination system that initial configuration is met specific projection object lens lighting requirement, have not yet to see the report of complete relevant design method.

Pertinent literature (US7456408) has proposed the design result of a cover compound eye illumination for extreme ultraviolet photolithographic, wherein only mention in the method for designing part aperture diaphragm that the mask face is used as system and come Method of Spreading Design, does not provide detailed design process.

Pertinent literature (US20070295919) has proposed the design result of a cover compound eye illumination for extreme ultraviolet photolithographic, this design is only that the arc area of 100mm * 8mm is effective for the field of illumination, does not propose how a cover designs the fly-eye illumination system that is fit to any extreme ultraviolet lithography projection objective on this design basis method.

Summary of the invention

The invention provides a kind of method for designing of extreme ultraviolet photolithographic fly-eye illumination system, the method can obtain to meet the design parameter of each device of specifying the extreme ultraviolet lithography projection objective lighting requirement fast based on the structure of existing fly-eye illumination system.

Realize that technical scheme of the present invention is as follows:

A kind of method for designing of extreme ultraviolet photolithographic fly-eye illumination system, this illuminator comprises light source, condenser, by diaphragm compound eye flat board and the dull and stereotyped even photosystem that forms of visual field compound eye, by relay lens group and glancing incidence mirror that the first relay lens and the second relay lens form, concrete steps are:

Step 101, determine illuminator distance of exit pupil L according to the parameter of the projection objective of appointment;

Step 102, determine that the axis of symmetry of glancing incidence mirror is the primary optical axis of illuminator, coordinate system (x, y, z) take primary optical axis as the z axle, set up according to the right-handed coordinate system principle as initial point in the summit of selected glancing incidence mirror, obtains the apex coordinate (Z of the first relay lens _G21, Y _G21), the apex coordinate (Z of the second relay lens _G22, Y _G22), the centre coordinate (Z of mask face _MASK, Y _MASK);

Step 103, according to described distance of exit pupil L and mask face centre coordinate (Z _MASK, Y _MASK), determine the coordinate (Z at illuminator emergent pupil center _EP, Y _EP);

Step 104, make emergent pupil center and the non-adjacent focal point F of glancing incidence mirror _Collector1Overlap, according to (Z _EP, Y _EP) calculate the radius of curvature R of glancing incidence mirror _G1

Step 105, make the non-adjacent focal point F of the first relay lens _Relay11Contiguous focal point F with the glancing incidence mirror _Collector2Overlap, according to (Z _G21, Y _G21) calculate the radius of curvature R of the first relay lens _G21

Step 106, make the contiguous focal point F of the second relay lens _Relay21Contiguous focal point F with the first relay lens _Relay12Overlap, according to (Z _G22, Y _G22) calculate the radius of curvature R of the second relay lens _G22

Step 107, to make the non-adjacent focus of condenser be the convergent point of even photosystem emergent ray, determines arranging of compound eye unit on the dull and stereotyped and visual field compound eye flat board of diaphragm compound eye in even photosystem according to described convergent point.

Further, the present invention determines that illuminator incides the size of the arc visual field on the mask face, the place arranges aperture diaphragm at the mask face, the described shape of the size of this aperture diaphragm visual field measure-alike, on illuminator emergent pupil face, a light source is set, send the chief ray of light according to light source on the emergent pupil face, regulate the angle of the first relay lens and the second relay lens.

Beneficial effect

The present invention is by determining the relative position relation between each parts focus, therefore when the projection objective for an appointment provides satisfactory illuminator, only need according to the relative position relation of determining, calculate the parameter of each parts, therefore make method for designing of the present invention go for different projection objectives.

Secondly, the present invention proposes a kind of design philosophy of reverse ray tracing, the picture of the thing (being light source) of reality being used as system, the picture (emergent pupil of illuminator) of reality is worked as crop, arc visual field on the mask face is arranged to the aperture diaphragm of system, this mentality of designing makes the technical requirement of original system image space be transformed into the technical requirement of object space, and the latter more easily realizes in design than the former.

Description of drawings

Fig. 1 is the typical structure schematic diagram of the existing extreme ultraviolet etching system of institute of the present invention foundation.

Fig. 2 is glancing incidence mirror structural representation.

Fig. 3 is the relay lens structural representation.

Fig. 4 is the optical collector structure schematic diagram.

Fig. 5 is typical extreme ultraviolet photolithographic arc visual field structural representation.

Fig. 6 is illuminator emergent pupil face position view.

Fig. 7 is the ray tracing schematic diagram of glancing incidence mirror in the invention process.

Fig. 8 is the ray tracing schematic diagram of glancing incidence mirror and relay lens 1 in the invention process.

Fig. 9 is the ray tracing schematic diagram of glancing incidence mirror and the G1 of system in the invention process.Figure 10 is the typical visual field compound eye schematic diagram of arranging.

Figure 11 is the typical diaphragm compound eye schematic diagram of arranging.

Figure 12 is not for comprising the fly-eye illumination system schematic diagram of condenser and light source.

Figure 13 is the schematic diagram of single imaging band location positioning.

Figure 14 is visual field compound eye grouping schematic diagram.

Figure 15 is diaphragm compound eye grouping schematic diagram.

Figure 16 is illuminator emergent pupil light distribution schematic diagram.

Figure 17 is the light distribution schematic diagram of illuminator on the mask face.

Embodiment

The present invention is described in detail below in conjunction with the drawings and specific embodiments.

Fig. 1 is a typical structure schematic diagram of extreme ultraviolet etching system.The extreme ultraviolet photolithographic fly-eye illumination system is the total reflection off-axis optical system, the structure of condenser need to be determined according to the characteristic of light source, so method for designing of extreme ultraviolet photolithographic fly-eye illumination system of the present invention, only find the solution for the parameter of even photosystem, relay lens group and glancing incidence mirror, for convenience of description, the structure to above-mentioned parts below is carried out predefined:

The label of glancing incidence mirror is made as G1, the label of relay lens group is made as G2, the label of even photosystem is made as G3.

As shown in Figure 2, the solid line on coordinate system right side represents the glancing incidence mirror, and the coordinate system left-hand broken line represents the hyperboloid with glancing incidence mirror symmetry, the focal point F on definition right side _Collector2Be the contiguous focus of glancing incidence mirror, the focal point F in left side _Collector1Non-adjacent focus for the glancing incidence mirror.

As shown in Figure 3, the solid line on coordinate system right side represents relay lens, and the focus on definition right side is the contiguous focus of relay lens, and the focus in left side is the non-adjacent focus of relay lens.

As shown in Figure 4, the solid line on coordinate system right side represents condenser, and the focus on definition right side is the contiguous focus of condenser, and the focus in left side is the non-adjacent focus of condenser.

Detailed process of the present invention is as follows:

Step 101, determine that according to the parameter of the projection objective of appointment exit pupil diameter D, the distance of exit pupil L of illuminator and illuminator incide the size of the arc visual field on the mask face, wherein the size of arc visual field comprises external diameter R, internal diameter r and the chord length d of arc visual field, as shown in Figure 5.Wherein the exit pupil diameter D of illuminator equals the entrance pupil diameter of projection objective, and the distance of exit pupil L(of illuminator is the distance between mask face and emergent pupil face) equal the entrance pupil distance of projection objective.

Step 102, the present invention are because the structure of selected fly-eye illumination system is determined, so the relative position relation between each parts is definite, and the aspheric surface quadratic coefficients on each parts is also determined simultaneously.

This step determines that the axis of symmetry of glancing incidence mirror is the primary optical axis of illuminator, and coordinate system (x, y, z) take primary optical axis as the z axle, set up according to the right-handed coordinate system principle as initial point in the summit of selected glancing incidence mirror; Because the summit of each optical element in native system all is in the Y-Z plane, according to the position relationship that each parts are determined relatively, obtain the apex coordinate (Z of the first relay lens _G21, Y _G21) and aspheric surface quadratic coefficients K _G21, the apex coordinate (Z of the second relay lens _G22, Y _G22) and aspheric surface quadratic coefficients K _G22, the centre coordinate (Z of mask face _MASK, Y _MASK) and the aspheric surface quadratic coefficients of glancing incidence mirror be K _G1

Step 103, according to described distance of exit pupil L and mask face centre coordinate (Z _MASK, Y _MASK), determine the coordinate (Z at illuminator emergent pupil center _EP, Y _EP).

According to the litho machine principle of work as can be known, on the center of illuminator emergent pupil face, mask face, the center of circle of arc visual field all is positioned on the primary optical axis of projection objective, and the mask face is perpendicular to this primary optical axis, as shown in Figure 6.According to described distance of exit pupil L and mask face centre coordinate (Z _MASK, Y _MASK), can determine the coordinate (Z at emergent pupil center _EP, Y _EP).

Step 104, make emergent pupil center and the non-adjacent focal point F of glancing incidence mirror _Collector1Overlap, calculate the radius-of-curvature of glancing incidence mirror; Concrete computation process is:

Emergent pupil center and glancing incidence vertex point apart from l be:

$l=\sqrt{z_{\mathrm{EP}}^2+Y_{\mathrm{EP}}^2}---\left(1\right)$

Because the glancing incidence mirror is hyperboloid, establishing in fact, axial length is a _G1, the imaginary axis is long is b _G1, have:

$L=a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}+\sqrt{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2+b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}---\left(2\right)$

$K_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}=-\frac{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2+b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}---\left(3\right)$

The a that calculates according to formula (2) and (3) _G1And b _G1, find the solution the radius of curvature R of glancing incidence mirror _G1, namely as shown in Equation (4):

$R_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}=\frac{b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000011.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}{a_{G1}}---\left(4\right)$

Because the face type of glancing incidence mirror is determined, therefore can utilize the radius of curvature R that calculates _G1, design the glancing incidence mirror.

Therefore be reversible due to light in the process of transmission, take out central point on the pupil face as the thing of system, obtain the structural representation of glancing incidence mirror by ray tracing, as shown in Figure 7.

in following process from step 105 to 107, the angle of each device is being adjusted the design philosophy that all is based on reverse ray tracing, the image planes of the object plane (being the plane at light source place) of reality being used as system, the object plane of the image planes (being the emergent pupil face of illuminator) of reality being used as system, the place arranges aperture diaphragm at the mask face, the size of this aperture diaphragm and the arc visual field described in step 101 measure-alike, on illuminator emergent pupil face, a light source is set, on the emergent pupil face, light source sends the chief ray of light, regulate the first relay lens, the angle of the second relay lens.This mentality of designing makes the technical requirement of original system image space be transformed into the technical requirement of object space, and the latter more easily realizes in design than the former.

Step 105, the long a of real axis that obtains according to step 104 _G1With the long b of the imaginary axis _G1, the contiguous focal point F of calculating glancing incidence mirror _Collector2Coordinate (Z _G1F, Y _G1F).Make the non-adjacent focal point F of the first relay lens _Relay11Contiguous focal point F with the glancing incidence mirror _Collector2Overlap, calculate the radius-of-curvature of the first relay lens; Concrete computation process is:

Because the first relay lens is ellipsoid, establish the long a of being of its major semi-axis _G21, minor semi-axis is long is b _G21, focal length is F _G21, have

$a_{G21}+F_{G21}=\sqrt{{(Z_{G21}-Z_{G1F})}^2+{(Y_{G21}-Y_{G1F})}^2}---\left(5\right)$

$K_{G21}=\frac{b_{G21}^2-a_{G21}^2}{a_{G21}^2}---\left(6\right)$

The a that calculates according to formula (5) and (6) _G21And b _G21, solve the radius of curvature R of glancing incidence mirror _G21, namely as shown in Equation (7):

$R_{G21}=\frac{b_{G21}^2}{a_{G21}}---\left(7\right)$

Because the face type of the first relay lens is determined, therefore can utilize the radius of curvature R that calculates _G21, design the first relay lens.

Determine the angle of the first relay lens: rotation the first relay lens guarantees that the incident angle of the chief ray of coming from the incident of emergent pupil face between 6 °～8 °, obtains the tiltangleθ of the first relay lens thus ₁, as shown in Figure 8.

Step 106, according to the first relay lens that step 105 is obtained, calculate the first contiguous focal point F of relay lens _Relay12Coordinate (Z _G21F, Y _G21F); Make the contiguous focal point F of the second relay lens _Relay21Contiguous focal point F with the first relay lens _Relay12Overlap, calculate the radius-of-curvature of the second relay lens; Concrete computation process is:

Because the second relay lens is ellipsoid, establishing its major semi-axis field is a _G22, minor semi-axis is long is b _G22, focal length is F _G22, have

$a_{G22}+F_{G22}=\sqrt{{(Z_{G22}-Z_{G21F})}^2+{(Y_{G21}-Y_{G21F})}^2}---\left(8\right)$

$K_{G22}=\frac{b_{G22}^2-a_{G22}^2}{a_{G22}^2}---\left(9\right)$

The a that calculates according to formula (8) and (9) _G22And b _G22, solve the radius of curvature R of glancing incidence mirror _G22, namely as shown in Equation (10):

$R_{G22}=\frac{b_{G22}^2}{a_{G22}}---\left(10\right)$

Because the face type of the second relay lens is determined, therefore can utilize the radius of curvature R that calculates _G22, design the second relay lens.

Determine the angle of the second relay lens: the fine setting the second relay lens make the light by its outgoing converge at a bit, this some the distance to the second relay lens 2 be not more than 1500mm and be not less than 1000mm; Rotate simultaneously the second relay lens, the angle that the chief ray that assurance is reflected from the first relay lens is incident to the second relay lens obtains the tiltangleθ of the second relay lens thus between 9 °～12 ° ₂, as shown in Figure 9.

Step 107, to make the non-adjacent focus of condenser be the convergent point (being the picture point of even photosystem) of even photosystem emergent ray, determines arranging of compound eye unit on the dull and stereotyped and visual field compound eye flat board of diaphragm compound eye in even photosystem according to described convergent point.

The below is further elaborated to the detailed process of step 107.

Step 201, the central point that sets out the pupil face are object point, place the diaphragm compound eye near the picture point that obtains dull and stereotyped after object point is through glancing incidence mirror and relay lens group, and the center of all diaphragm compound eyes unit all is positioned on this flat board; The rotary diaphragm compound eye is dull and stereotyped, guarantees to incide chief ray incident angle on diaphragm compound eye flat board between 6 °～8 ° from the light of object point outgoing, obtains thus the tiltangleθ of diaphragm compound eye flat board _PF

Step 202, to place the visual field compound eye on the light path of diaphragm compound eye folded light beam dull and stereotyped, guarantees that simultaneously visual field compound eye flat board does not block the light of the second relay lens reflection, and the center of all visual field compound eye units all is positioned on this flat board; Rotation visual field compound eye is dull and stereotyped, guarantees to be incident to chief ray incident angle on the compound eye flat board of visual field between 9 °～12 ° from the light of object point outgoing, obtains thus the tiltangleθ of visual field compound eye flat board _FF

Step 203, because double compound eye does not play amplification, after the size of relay lens group and glancing incidence mirror was determined, the enlargement ratio of illuminator can be determined; Therefore this step is according to the size of the enlargement ratio Γ of illuminator and arc visual field, determines the length of rectangle compound eye on the compound eye of visual field unit and wide, and the length of establishing compound eye unit is l _a, wide is l _b:

$l_a=\frac{d}{\mathrm{\&Gamma;}}$ $l_b=\frac{R-r}{\mathrm{\&Gamma;}}$

Wherein, d is the chord length of arc visual field, and R is the external diameter of arc visual field, and r is the internal diameter of arc visual field;

Step 204, allow light source be full of whole emergent pupil, obtain through being incident to the size of hot spot on the compound eye flat board of visual field after glancing incidence mirror, relay lens group and diaphragm compound eye, and above-mentioned spot size is defined as the size of visual field compound eye flat board, the size of the visual field compound eye unit that integrating step 203 is calculated is determined arranging of visual field compound eye unit; Usually visual field compound eye unit is arranged in the zone of sub-circular, and the reflecting surface of visual field compound eye unit is as shown in figure 10 rectangular.

Step 205, determine the size of diaphragm compound eye unit and arrange.Produce distortion because the glancing incidence mirror will make emergent pupil, so the diaphragm compound eye should be taked arranging of precorrection distortion, namely the diaphragm compound eye is arranged in the zone of sub-circular, and the reflecting surface of its each compound eye unit is rounded, and diameter is got 8～11mm usually, as shown in figure 11; Therefore this only carry out brief description to it for prior art.

Step 206, determining the contraposition relation of visual field compound eye and diaphragm compound eye, have relation one to one between visual field compound eye unit and diaphragm compound eye unit, is that each corresponding diaphragm compound eye of visual field compound eye unit is first.The process of determining is: two row's compound eyes are divided into respectively some parts, in large zone according to nearby principle, be that roughly corresponding central stop compound eye is first in visual field, center compound eye unit, visual field, edge compound eye unit roughly visual field, corresponding edge compound eye is first, thereby determine compound eye contraposition relation: in the zonule, can be equally according to nearby principle, guarantee that the angle of inclination of each compound eye unit is as far as possible little, also can according to intersecting corresponding principle, guarantee to obtain on the emergent pupil face maximum illumination uniformity.

Step 207, to make the non-adjacent focus of condenser be the convergent point of even photosystem emergent ray, according to the visual field compound eye unit that determines in step 206 and the first contraposition relation that gets of diaphragm compound eye, determine the coordinate of the diaphragm compound eye unit that selected object point is corresponding and coordinate and the pitch angle of pitch angle and diaphragm compound eye unit corresponding visual field compound eye unit by ray tracing, make the light of outgoing converge on the non-adjacent focus of condenser.

The detailed process of step 207 is:

Choose some things as illuminator on the emergent pupil face, light incides on diaphragm compound eye flat board after through system glancing incidence mirror, relay lens group, and the intersection point of chief ray on diaphragm compound eye flat board is the coordinate of diaphragm compound eye unit corresponding to this object point; According to the compound eye contraposition relation of determining in step 206, suitable pitch angle of rotary diaphragm compound eye unit is accurately incided in corresponding visual field compound eye unit the chief ray by the first outgoing of this diaphragm compound eye.Principle of work according to the compound eye illumination imaging systems, the visual field compound eye can converge to all incident raies picture point F, the F point is the non-adjacent focus of condenser, (Figure 12 does not comprise that light-source system and condenser are at interior lighting system structure schematic diagram as shown in figure 12, focal point F is the non-adjacent focus of condenser, face EP is the emergent pupil face, and in method for designing of the present invention, what the mask face was placed is the aperture diaphragm of a printing opacity).Therefore, for the light that makes the first outgoing of this visual field compound eye all converges to the F point, must give its suitable pitch angle.Just determined that thus the corresponding a pair of diaphragm compound eye of this imaging band is first, coordinate and the pitch angle of visual field compound eye unit.The schematic diagram of single imaging band location positioning as shown in figure 12.Again get a little on the emergent pupil face, determine the method for coordinate and angle according to above-mentioned single imaging band, until on diaphragm compound eye and visual field compound eye coordinate and the pitch angle of all compound eyes units all determine.

Embodiment of the present invention:

As shown in table 1, at first determine the size of arc visual field on exit pupil diameter, distance of exit pupil and the mask face of illuminator for the parameter of the extreme ultraviolet lithography projection objective of lab design.

Table 1

Exit pupil diameter D	162.32mm
		Distance of exit pupil L	1246.5mm
Arc visual field external diameter	124mm
		Arc visual field internal diameter	116mm
Arc visual field chord length	104mm

As shown in table 2, on the basis of existing extreme ultraviolet photolithographic fly-eye illumination system, primary optical axis take the axis of symmetry of G1 system as whole illuminator obtains respectively apex coordinate and curved surface quadratic coefficients and the emergent pupil centre coordinate of each element of mask face center, G1, G2 system.

Table 2

	The Z coordinate	The Y coordinate	The quadric surface coefficient
				Mask face center	167.6228mm	-237.3910mm	-
Glancing incidence mirror G1	0	0	61.4278
				Relay lens 1	470.6719mm	-1087.2000	-943.7142
Relay lens 2	300.000mm	-654.9322mm	-730
				The emergent pupil center	-1065.7365mm	0	-

As shown in table 3, can calculate face shape parameter and the pitch angle of the G1 of system, G2 according to the data in table 2.

Table 3

	Radius R	The quadric surface coefficient	The pitch angle
				Mask face center	167.6228mm	-	4.4°
Glancing incidence mirror G1	0	61.4278	0
				Relay lens 1	470.6719mm	-943.7142	-68.1055°
Relay lens 2	300.000mm	-730	-51.6698°
				The emergent pupil center	-1065.7365mm	-	4.4°

Foundation table 1～table 3 is obtained system carry out the picture point that ray tracing can obtain light source, place the diaphragm compound eye dull and stereotyped near this point; Visual field compound eye flat board is placed in the appropriate location after the diaphragm compound eye, guarantees that light path is unobstructed.The data that obtain thus double compound eye are as shown in table 4.

Table 4

	The Z coordinate	The Y coordinate	The pitch angle
				PF is dull and stereotyped	1519.6180	-1411.4138	-35.24°
FF is dull and stereotyped	539.0418	-895.7333	-38.24°

The system that foundation table 1～table 4 is obtained carries out ray tracing can determine that the coordinate of focal point F is (1600,1542.4900).The dull and stereotyped glazed thread of visual field compound eye this moment distributed areas are the circles that radius is 160mm, then can determine the size of single visual field compound eye unit in conjunction with the enlargement ratio of this illuminator: long 80mm, and wide 5.1mm, totally 216, visual field compound eye unit, it is arranged as shown in figure 14.

According to arranging and total compound eye unit number of visual field compound eye, can determine arranging as shown in figure 15 of diaphragm compound eye unit, single visual field compound eye unit reflecting surface is rounded, and its diameter is 10mm.

As Figure 14, shown in Figure 15, can obtain the contraposition relation of visual field compound eye and diaphragm compound eye according to nearby principle.In this example, the compound eye unit on each compound eye flat board is divided into 13 zones, carries out contraposition according to nearby principle.

As shown in table 5, table 6, according to contraposition relation shown in Figure 15, evenly choose 216 points as object point on the emergent pupil face, can determine coordinate and the pitch angle of visual field compound eye unit that 216 imaging bands are corresponding and diaphragm compound eye unit by ray tracing.

A pointolite is placed at the focal point F place that obtains in above-mentioned steps, successively the G3 of system, G2, G1 is carried out ray tracing and emulation, can obtain an arc visual field on the mask face of appointment, as shown in figure 16; Can obtain by ray tracing and emulation the circle that a diameter is the 160mm left and right on the emergent pupil face of system, as shown in figure 17.Result by Figure 16 and Figure 17 can prove, simple possible of the present invention for the extreme ultraviolet lithography projection objective of any appointment, all can obtain satisfactory illuminator fast on existing fly-eye illumination system basis.

In sum, these are only preferred embodiment of the present invention, is not for limiting protection scope of the present invention.Within the spirit and principles in the present invention all, any modification of doing, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (3)

1. the method for designing of an extreme ultraviolet photolithographic fly-eye illumination system, this illuminator comprises light source, condenser, the relay lens group and the glancing incidence mirror that form by diaphragm compound eye flat board and the dull and stereotyped even photosystem that forms of visual field compound eye, by the first relay lens and the second relay lens, determine illuminator distance of exit pupil L according to the parameter of the projection objective of appointment, it is characterized in that, concrete steps are:

Step 101, determine that the axis of symmetry of glancing incidence mirror is the primary optical axis of illuminator, coordinate system (x, y, z) take primary optical axis as the z axle, set up according to the right-handed coordinate system principle as initial point in the summit of selected glancing incidence mirror, obtains the apex coordinate (Z of the first relay lens _G21, Y _G21), the apex coordinate (Z of the second relay lens _G22, Y _G22), the centre coordinate (Z of mask face _MASK, Y _MASK);

Step 102, according to described distance of exit pupil L and mask face centre coordinate (Z _MASK, Y _MASK), determine the coordinate (Z at illuminator emergent pupil center _EP, Y _EP);

Step 103, make emergent pupil center and the non-adjacent focal point F of glancing incidence mirror _Collector1Overlap, according to (Z _EP, Y _EP) calculate the radius of curvature R of glancing incidence mirror _G1

Step 104, make the non-adjacent focal point F of the first relay lens _Relay11Contiguous focal point F with the glancing incidence mirror _Collector2Overlap, according to (Z _G21, Y _G21) calculate the radius of curvature R of the first relay lens _G21

Step 105, make the contiguous focal point F of the second relay lens _Relay21Contiguous focal point F with the first relay lens _Relay12Overlap, according to (Z _G22, Y _G22) calculate the radius of curvature R of the second relay lens _G22

Step 106, to make the non-adjacent focus of condenser be the convergent point of even photosystem emergent ray, determines arranging of compound eye unit on the dull and stereotyped and visual field compound eye flat board of diaphragm compound eye in even photosystem according to described convergent point.

2. the method for designing of extreme ultraviolet photolithographic fly-eye illumination system according to claim 1, it is characterized in that, determine that described illuminator incides the size of the arc visual field on the mask face, the place arranges aperture diaphragm at the mask face, the described shape of the size of this aperture diaphragm visual field measure-alike, on illuminator emergent pupil face, a light source is set, sends the chief ray of light according to light source on the emergent pupil face, regulate the angle of the first relay lens and the second relay lens.

3. the method for designing of extreme ultraviolet photolithographic fly-eye illumination system according to claim 1, is characterized in that, the detailed process of described step 106 is:

Step 201, the central point that sets out the pupil face are object point, place the diaphragm compound eye near the picture point that obtains dull and stereotyped after object point is through glancing incidence mirror and relay lens group, and the center of all diaphragm compound eyes unit all is positioned on this flat board; The rotary diaphragm compound eye is dull and stereotyped, guarantees to incide chief ray incident angle on diaphragm compound eye flat board between 6 °～8 ° from the light of object point outgoing;

Step 202, to place the visual field compound eye on the light path of diaphragm compound eye folded light beam dull and stereotyped, guarantees that simultaneously visual field compound eye flat board does not block the light of the second relay lens reflection, and the center of all visual field compound eye units all is positioned on this flat board; Rotation visual field compound eye is dull and stereotyped, guarantees to be incident to chief ray incident angle on the compound eye flat board of visual field between 9 °～12 ° from the light of object point outgoing;

Step 203, according to the size of the enlargement ratio Γ of illuminator and arc visual field, determine the length of rectangle compound eye on the compound eye of visual field unit and wide, the length of establishing compound eye unit is l _a, wide is l _b:

$l_a=\frac{d}{\mathrm{\&Gamma;}}$ $l_b=\frac{R-r}{\mathrm{\&Gamma;}}$

Wherein, d is the chord length of arc visual field, and R is the external diameter of arc visual field, and r is the internal diameter of arc visual field;

Step 204, allow light source be full of the emergent pupil of whole illuminator, obtain the size that is incident to hot spot on the compound eye flat board of visual field after glancing incidence mirror, relay lens group and diaphragm compound eye flat board, and above-mentioned spot size is defined as the size of visual field compound eye flat board, and the size of the visual field compound eye unit of integrating step 203 calculating, determine arranging of visual field compound eye unit;

Step 205, determine the size of diaphragm compound eye unit and arrange; Be that the diaphragm compound eye should be taked arranging of precorrection distortion, the reflecting surface of its each compound eye unit is rounded, and the span of diameter is 8～11mm;

Step 206, determine the contraposition relation of visual field compound eye unit and diaphragm compound eye unit, i.e. a corresponding diaphragm compound eye unit of each visual field compound eye unit;

Step 207, to make the non-adjacent focus of condenser be the convergent point of even photosystem emergent ray, according to the visual field compound eye unit that determines in step 206 and the first contraposition relation that gets of diaphragm compound eye, determine the coordinate of the diaphragm compound eye unit that selected object point is corresponding and coordinate and the pitch angle of pitch angle and diaphragm compound eye unit corresponding visual field compound eye unit by ray tracing, make the light of outgoing converge on the non-adjacent focus of condenser.

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