CN102629082A - 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 behind the mask, light is incident on the wafer that scribbles photoresist via optical projection system, so just mask pattern is replicated on the wafer.

Extreme ultraviolet photolithographic EUVL is to be that the extreme ultraviolet EUV ray of 11～14nm is the microelectronics photoetching technique of exposure light source with wavelength, is applicable to that characteristic dimension 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 this system's most important component is illuminator and projection objective system.The illuminator major function is even illumination, control exposure dose to be provided 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 accomplish 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 illumination 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 ripe, is convenient to control, and is easy to realize that 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: light source, condenser, even photosystem (comprise diaphragm compound eye dull and stereotyped with visual field compound eye flat board), relay lens group (comprising first relay lens and second relay lens) and glancing incidence mirror according to the direction of beam propagation; 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 an ellipsoid, and plunderring into mirror is hyperboloid.The parameter of every suit fly-eye illumination system all be 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, the parameter of each optical element all possibly change in the illuminator.Therefore, be necessary to work out a kind of method, can be met the fly-eye illumination system of specific projection object lens lighting requirement sooner, more accurately according to existing initial configuration, do not see the report of complete relevant design method at present as yet.

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

Pertinent literature (US20070295919) has proposed a cover compound eye design of Lighting result to extreme ultraviolet photolithographic; This design is that the arc area of 100mm * 8mm is effective to the field of illumination only, does not propose how a cover designs the fly-eye illumination system that is fit to any extreme ultraviolet photolithographic 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, this method can obtain to meet the design parameter of each device of specifying extreme ultraviolet photolithographic projection objective lighting requirement fast based on the structure of existing fly-eye illumination system.

Realize that technical scheme of the present invention is following:

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 of forming of visual field compound eye, by relay lens group and glancing incidence mirror that first relay lens and second relay lens are formed, concrete steps are:

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

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

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

Step 104, make emergent pupil center and the non-contiguous 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-contiguous focal point F of 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 first relay lens _G21

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

Step 107, the non-contiguous focus that makes condenser are the convergent point of even photosystem emergent ray, according to said convergent point confirm in the even photosystem diaphragm compound eye dull and stereotyped with visual field compound eye flat board on first the arranging of compound eye.

Further; The present invention confirms that illuminator incides the size of the arc visual field on the mask face; The place is provided with aperture diaphragm at the mask face, and the said shape of the size of this aperture diaphragm visual field measure-alike is provided with a light source on illuminator emergent pupil face; Send the chief ray of light, the angle of regulating first relay lens and second relay lens according to light source on the emergent pupil face.

Beneficial effect

The present invention is through confirming the relative position relation between each parts focus; Therefore when the projection objective that is an appointment provides satisfactory illuminator; Only need according to the relative position relation of confirming; 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 thing (being light source) of reality is used as the picture of system, the picture (emergent pupil of illuminator) of reality is worked as crop, the 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 realizes in design than the former more easily.

Description of drawings

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

Fig. 2 is a glancing incidence mirror structural representation.

Fig. 3 is the relay lens structural representation.

Fig. 4 is the optical collector structure synoptic diagram.

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

Fig. 6 is an illuminator emergent pupil face position view.

Fig. 7 is the ray tracing synoptic diagram of glancing incidence mirror in the present invention's enforcement.

Fig. 8 is the ray tracing synoptic diagram of glancing incidence mirror and relay lens 1 in the present invention's enforcement.

Fig. 9 is the ray tracing synoptic diagram of glancing incidence mirror and the G1 of system in the present invention's enforcement.Figure 10 is the typical visual field compound eye synoptic diagram of arranging.

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

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

Figure 13 is the synoptic diagram that single imaging channel position is confirmed.

Figure 14 is a visual field compound eye grouping synoptic diagram.

Figure 15 is a diaphragm compound eye grouping synoptic diagram.

Figure 16 is an illuminator emergent pupil light distribution synoptic diagram.

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

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is elaborated.

Fig. 1 is a typical structure synoptic 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 be confirmed 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 convenience of description, below the structure of above-mentioned parts carried out predefined to the parameter of even photosystem, relay lens group and glancing incidence mirror:

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 is represented the glancing incidence mirror, and the coordinate system left-hand broken line is represented 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-contiguous focus for the glancing incidence mirror.

As shown in Figure 3, the solid line on coordinate system right side is represented 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-contiguous focus of relay lens.

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

Detailed process of the present invention is following:

Step 101, follow according to the parameter of the projection objective of appointment and confirm that exit pupil diameter D, distance of exit pupil L and the illuminator of 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, and is 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 (being the distance between mask face and the emergent pupil face) equals the entrance pupil distance of projection objective.

Step 102, the present invention are owing to the structure of selected fly-eye illumination system is confirmed, so the relative position relation between each parts confirms that the aspheric surface quadratic coefficients on each parts is also confirmed simultaneously.

This step confirms that the axis of symmetry of glancing incidence mirror is the primary optical axis of illuminator, and the summit of selected glancing incidence mirror is the z axle as initial point with the primary optical axis, according to the right-handed coordinate system principle set up coordinate system (x, y, z); Because the summit of each optical element all is in the Y-Z plane in the native system,, obtain the apex coordinate (Z of first relay lens according to the position relation that each parts is confirmed relatively _G21, Y _G21) and aspheric surface quadratic coefficients K _G21, the apex coordinate (Z of 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 said distance of exit pupil L and mask face centre coordinate (Z _MASK, Y _MASK), confirm the coordinate (Z at emergent pupil center _EP, Y _EP).

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

Step 104, make emergent pupil center and the non-contiguous 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 a hyperboloid, establishing in fact, axial length is a _G1, the imaginary axis is long to be b _G1, then have:

$l=a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}+\sqrt{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2+b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}---\left(2\right)$

$K_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}=-\frac{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2+b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}{a_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}---\left(3\right)$

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, promptly shown in formula (4):

$R_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}=\frac{b_{\mathrm{<figure-callout\; id="1"\; label="G"\; filenames="HDA0000158542040000012.png,HDA0000158542040000021.png"\; state="\{\{state\}\}">G</figure-callout>}1}^2}{a_{G1}}---\left(4\right)$

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

Because light is reversible in the process of transmission, therefore take out central point on the pupil face as the thing of system, obtain the structural representation of glancing incidence mirror through ray tracing, as shown in Figure 7.

In the 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 object plane of reality (being the plane at light source place) is used as the image planes of system, the image planes (being the emergent pupil face of illuminator) of reality are used as the object plane of system, the place is provided with aperture diaphragm at the mask face; The size of this aperture diaphragm and the arc visual field described in the step 101 measure-alike; On illuminator emergent pupil face, a light source is set, light source sends the chief ray of light on the emergent pupil face, regulates the angle of first relay lens, 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 realizes in design than the former more easily.

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-contiguous focal point F of first relay lens _Relay11Contiguous focal point F with the glancing incidence mirror _Collector2Overlap, calculate the radius-of-curvature of first relay lens; Concrete computation process is:

Because first relay lens is an ellipsoid, establish the long a of being of its major semi-axis _G21, minor semi-axis is long to be b _G21, focal length is F _G21, then 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, promptly shown in formula (7):

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

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

Confirm the angle of first relay lens: rotate first relay lens, the incident angle of the chief ray that guarantees to come from the incident of emergent pupil face obtains the tiltangle of first relay lens thus between 6 °～8 ° ₁, as shown in Figure 8.

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

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

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

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

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

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

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

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

Step 107, the non-contiguous focus that makes condenser are the convergent point (i.e. the picture point of even photosystem) of even photosystem emergent ray, according to said convergent point confirm in the even photosystem diaphragm compound eye dull and stereotyped with visual field compound eye flat board on first the arranging of compound eye.

Detailed process in the face of step 107 is further elaborated down.

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

Step 202, on the light path of diaphragm compound eye folded light beam, to place the visual field compound eye dull and stereotyped, guarantees that simultaneously visual field compound eye flat board does not block the light of second relay lens reflection, and the center of all visual field compound eyes 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 the dull and stereotyped tiltangle of visual field compound eye thus _FF

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

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

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, let 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 behind glancing incidence mirror, relay lens group and the diaphragm compound eye; And above-mentioned spot size confirmed as the dull and stereotyped size of visual field compound eye; The size of the visual field compound eye unit that integrating step 203 is calculated is confirmed 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 rectangular shown in figure 10.

Step 205, confirm the size of diaphragm compound eye unit and arrange.Because the glancing incidence mirror will make emergent pupil produce distortion, so the diaphragm compound eye should be taked arranging of precorrection distortion, promptly 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, and is shown in figure 11; Therefore this only carry out brief description to it for prior art.

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

Step 207, the non-contiguous focus that makes condenser are the convergent point of even photosystem emergent ray; First that contraposition concerns according to visual field compound eye unit that confirms in the step 206 and diaphragm compound eye; Confirm the coordinate of the diaphragm compound eye unit that selected object point is corresponding and the coordinate and the pitch angle of pitch angle and pairing visual field compound eye unit of diaphragm compound eye unit through ray tracing, make the light of outgoing converge on the non-contiguous focus of condenser.

The detailed process of step 207 is:

On the emergent pupil face, choose some things as illuminator, incide on the diaphragm compound eye flat board after light process system glancing incidence mirror, the relay lens group, the intersection point of chief ray on diaphragm compound eye flat board is the coordinate of the corresponding diaphragm compound eye unit of this object point; According to the compound eye contraposition relation of confirming in the step 206, appropriate tilt angle of rotary diaphragm compound eye unit is accurately incided in the corresponding visual field compound eye unit chief ray by this diaphragm compound eye unit outgoing.Principle of work according to the compound eye illumination imaging systems; The visual field compound eye can converge to picture point F with all incident raies, and the F point is the non-contiguous focus of condenser, and shown in figure 12 (Figure 12 does not comprise that light-source system and condenser are at interior lighting system structure synoptic diagram; Focal point F is the non-contiguous 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 this visual field compound eye unit outgoing all converges to the F point, must give its appropriate tilt angle.Just confirmed that thus the pairing a pair of diaphragm compound eye of this imaging passage is first, the coordinate and the pitch angle of visual field compound eye unit.The synoptic diagram that single imaging channel position is confirmed is shown in figure 12.On the emergent pupil face, get again a little, confirm the method for coordinate and angle according to above-mentioned single imaging passage, up to till the first coordinate of all compound eyes and pitch angle are all confirmed on diaphragm compound eye and the visual field compound eye.

Embodiment of the present invention:

As shown in table 1, at first confirm the size of arc visual field on exit pupil diameter, distance of exit pupil and the mask face of illuminator to the parameter of the extreme ultraviolet photolithographic 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; Axis of symmetry with the G1 system is the primary optical axis of whole illuminator, obtains apex coordinate and the curved surface quadratic coefficients and the emergent pupil centre coordinate of mask face center, G1, each element of G2 system respectively.

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 the 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°

Carry out the picture point that ray tracing can obtain light source to obtaining system according to table 1～table 3, it is dull and stereotyped near this point, to place the diaphragm compound eye; To place the visual field compound eye dull and stereotyped in the appropriate location behind the diaphragm compound eye, guarantees that light path does not have to block.The data that obtain double compound eye thus 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 obtains according to table 1～table 4 is carried out ray tracing can confirm 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, combine the enlargement ratio of this illuminator can confirm the size that single visual field compound eye is first again: long 80mm, and wide 5.1mm, totally 216 in visual field compound eye unit, it arranges shown in figure 14.

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

Like 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 instance the compound eye unit on each compound eye flat board is divided into 13 zones, carries out contraposition according to nearby principle.

Shown in table 5, table 6, according to contraposition relation shown in Figure 15, on the emergent pupil face, evenly choose 216 points as object point, can confirm the visual field compound eye unit of 216 imaging passage correspondences and the coordinate and the pitch angle of diaphragm compound eye unit through ray tracing.

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

In sum, more than being merely preferred embodiment of the present invention, is not to be used to limit protection scope of the present invention.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within 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, relay lens group and the glancing incidence mirror formed by diaphragm compound eye flat board and the dull and stereotyped even photosystem of forming of visual field compound eye, by first relay lens and second relay lens; It is characterized in that concrete steps are:

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

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

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

Step 104, make emergent pupil center and the non-contiguous 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-contiguous focal point F of 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 first relay lens _G21

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

Step 107, the non-contiguous focus that makes condenser are the convergent point of even photosystem emergent ray, according to said convergent point confirm in the even photosystem diaphragm compound eye dull and stereotyped with visual field compound eye flat board on first the arranging of compound eye.

2. according to the method for designing of the said extreme ultraviolet photolithographic fly-eye illumination system of claim 1; It is characterized in that confirm that said illuminator incides the size of the arc visual field on the mask face, the place is provided with aperture diaphragm at the mask face; The said 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, the angle of regulating first relay lens and second relay lens according to light source on the emergent pupil face.

3. bring up the method for designing of illuminator according to the said extreme ultraviolet photolithographic of claim 1, it is characterized in that the detailed process of said step 107 is:

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

Step 202, on the light path of diaphragm compound eye folded light beam, to place the visual field compound eye dull and stereotyped, guarantees that simultaneously visual field compound eye flat board does not block the light of second relay lens reflection, and the center of all visual field compound eyes 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 enlargement ratio Γ of illuminator and the size of arc visual field, confirm the length of the unit of rectangle compound eye on the compound eye of visual field and wide, the length of establishing compound eye unit is l _a, wide is l _bThen:

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

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, let light source be full of the emergent pupil of whole illuminator; Obtain the size that behind glancing incidence mirror, relay lens group and diaphragm compound eye flat board, is incident to hot spot on the compound eye flat board of visual field; And above-mentioned spot size confirmed as the dull and stereotyped size of visual field compound eye; And the size of the visual field compound eye unit of integrating step 203 calculating, confirm arranging of visual field compound eye unit;

Step 205, confirm 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, confirm the contraposition relation of visual field compound eye unit and diaphragm compound eye unit, i.e. each corresponding diaphragm compound eye unit of visual field compound eye unit;

Step 207, the non-contiguous focus that makes condenser are the convergent point of even photosystem emergent ray; First that contraposition concerns according to visual field compound eye unit that confirms in the step 206 and diaphragm compound eye; Confirm the coordinate of the diaphragm compound eye unit that selected object point is corresponding and the coordinate and the pitch angle of pitch angle and pairing visual field compound eye unit of diaphragm compound eye unit through ray tracing, make the light of outgoing converge on the non-contiguous focus of condenser.

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