TWI574123B - Exposure apparatus and design method of exposure apparatus - Google Patents

Description

Exposure device and design method of exposure device

The present invention relates to an exposure apparatus which can be used, for example, in the manufacture of a semiconductor, and a design method of the exposure apparatus.

For the illumination of an exposure apparatus used in the production of a semiconductor or the like, for example, ultraviolet rays can be used. Therefore, a plurality of lamps represented by a high pressure discharge lamp are combined and used for illumination of an exposure apparatus. Further, it is used as an integrator on the exposure apparatus, and the integrator is a lens body for receiving light from a plurality of lamps and improving the uniformity of the light.

A lamp such as this may employ a lamp having an ability corresponding to the amount of light required by the exposure device, but in the case where it is desired to satisfy the capability with one lamp (i.e., "1 lamp type"), in case Once the light cannot be emitted from the lamp due to a malfunction or the like, the exposure operation itself must be interrupted. Therefore, it is usually carried out using a plurality of lamps having a small capacity, so that it can supply the amount of light required for the exposure device (for example, Patent Document 1).

Prior Technical Literature Patent Literature

Patent Document 1: (Japanese) Special Publication No. 2010-72571

In the past, in the case where a lamp group composed of a plurality of lamps is used in an exposure device, if the lamp is brought closer to the upper and lower ends or the left and right ends of the lamp group, the optical axis of the lamp is relative to When the angle at which the angle of the central axis of the integrator is larger is considered in consideration of the arrangement angle of the lamp, it is considered that the number of lamps can be increased as much as possible according to the amount of light required for exposure. That is, it is considered that the longitudinal and lateral dimensions of the lamp group can be as large as possible.

However, the inventors have obtained the cognitive finding that when the angle of the optical axis of the lamp with respect to the central axis of the integrator increases, light from a lamp located outside the angle may not be helpful. Effective light for exposure. That is, although the general case is that an exposure device using a plurality of lamps is used, there is still room for improvement as to how such a plurality of lamps should be arranged.

Accordingly, it is an object of the present invention to provide an exposure apparatus in which a plurality of lamps are most suitably disposed, and a method of designing an exposure apparatus in which a plurality of lamps are most suitably disposed.

According to an aspect of the present invention, an exposure apparatus characterized by comprising: a lamp group composed of a plurality of lamps; and receiving light from the plurality of lamps and enhancing the light is provided. A uniform integrator, and satisfying the following conditional expressions 1 and 2, conditional expression 1: a≦tan θ ₁ × L × 2

Condition 2: θ _{1 -} θ ₂ = θ ₃

However, in the formula a: the longitudinal and lateral dimensions of the lamp group

L: the distance from the light exit position of the lamp group to the incident position of the integrator

θ ₁ : the maximum of the angle formed by the optical axis of each lamp and the central axis of the integrator

θ ₂ : aperture angle of light from each lamp

θ ₃ : the incident angle of a single fly-eye lens carried by the integrator.

Further, it is preferable that the lamp is a discharge lamp, and the electrode interval of the discharge lamp is set to be 0.8 mm or more and 1.5 mm or less.

Further, it is preferable that a convex lens is disposed on the surface side of the integrator facing the lamp group.

Further, it is preferable that a lamp front lens for reducing the diffusion of light from the lamp is disposed on the surface side of the lamp facing the integrator.

According to another aspect of the present invention, there is provided a method of designing an exposure apparatus having the following features, characterized in that: a lamp set composed of a plurality of lamps, and a light for receiving light from the plurality of lamps, and An integrator that increases the uniformity of the light, and satisfies the following conditional expressions 1 and 2, Conditional Formula 1: a≦tan θ ₁ × L × 2

Condition 2: θ _{1 -} θ ₂ = θ ₃

But, in the formula a: longitudinal and lateral dimensions of the lamp group

L: the distance from the light exit position of the lamp group to the incident position of the integrator

θ ₁ : the maximum of the angle formed by the optical axis of each lamp and the central axis of the integrator

θ ₂ : aperture angle of light from each lamp

θ ₃ : the incident angle of a single fly-eye lens carried by the integrator.

According to the present invention, it is possible to provide an exposure apparatus in which a plurality of lamps are most suitably disposed, and a design method of an exposure apparatus in which a plurality of lamps are most suitably disposed.

10‧‧‧Exposure device

11‧‧‧Lights

12‧‧‧ lights

14‧‧‧ integrator

16‧‧‧ concave mirror

18‧‧‧ illuminated surface

20‧‧‧ lamp body

22‧‧‧Mirror

24‧‧‧reflecting surface

25‧‧‧Glossy

26‧‧‧Incoming surface

28‧‧‧ shot surface

30‧‧‧Future eye lens

50‧‧‧ convex lens

52‧‧‧ (convex lens) lens center

60‧‧‧ lamp front lens

102‧‧‧Lighting tube department

104‧‧‧ Sealing Department

106‧‧‧Internal space

108‧‧‧Foil

110‧‧‧Electrode

112‧‧‧Guide bars

114‧‧‧ Mercury

X‧‧‧ Exposure objects

θ ₁ ‧‧‧ (integrator) effective angle of incidence

θ ₂ ‧‧‧Aperture angle of light from each lamp

Angle of incidence of a single fly-eye lens carried by the θ ₃ ‧‧‧ integrator

CL‧‧‧ (integrator) central axis

LCL‧‧‧ (light) optical axis

V‧‧‧ (light group) longitudinal dimensions

H‧‧‧ (light group) lateral dimensions

a‧‧‧Digital and transverse dimensions of the light group

θ‧‧‧An angle formed by the central axis of the integrator and the optical axis of the lamp

The distance from the light exit surface 25 of the lamp 12 to the entrance face 26 of the integrator 14

Focus of the F‧‧· integrator

G‧‧‧ Straight line

J‧‧‧ Straight line

S‧‧‧ (light group) light exit position

R‧‧‧ (integrator) incident position

D‧‧‧Lights 12 arranged farthest from the center of the light group 11

A‧‧‧ Height of integrator 14

Fig. 1 is a view showing an exposure apparatus 10 of an embodiment.

FIG. 2 is a diagram showing an example of the lamp 12.

FIG. 3 is a view showing an example of the lamp body 20.

4 shows the longitudinal dimension V and the lateral dimension H of the lamp group 11, (a) is a longitudinal sectional view, and (b) is a front view.

Fig. 5 is a view for explaining "integrator incident angle θ ₃ ".

Fig. 6 is a view showing the positional relationship of the lamp group 11 and the integrator 14.

Fig. 7 is a graph showing the relationship between the angle θ formed by the central axis CL of the integrator 14 and the optical axis LCL of the lamp 12, and the amount of light that contributes to the exposure of the object X to be exposed.

Fig. 8 is a view showing the positional relationship between the lamp group 11 and the integrator 14 of the other embodiment.

Figure 9 is an enlarged view of the periphery of the integrator 14 of the embodiment shown in Figure 8.

Fig. 10 is a view showing the positional relationship between the lamp group 11 and the integrator 14 of still another embodiment.

Fig. 1 shows an exposure apparatus 10 to which an embodiment of the present invention is applied. The exposure device 10 generally has a lamp group 11, an integrator 14, a concave mirror 16, and an irradiation surface 18.

The light group 11 is composed of a plurality of lamps 12. The lamp 12 emits light including a wavelength suitable for exposure of the exposure target X. Although the type of the lamp 12 is not particularly limited, in the present specification, a case where a high pressure discharge lamp is used as the lamp 12 will be described as an example.

As shown in FIG. 2, each of the lamps 12 is substantially provided with a lamp body 20 and a mirror 22.

On the lamp body 20, as described above, a high pressure discharge lamp is used as an example. As shown in FIG. 3, the lamp body 20 has an arc tube portion 102 and a pair of sealing portions 104 extending from the arc tube portion 102. Further, the arc tube portion 102 and the pair of sealing portions 104 are integrally formed of quartz glass. Further, an internal space 106 sealed by the sealing portion 104 is formed in the arc tube portion 102. Further, a foil 108 made of molybdenum is embedded in each of the sealing portions 104.

Further, the lamp body 20 is provided with a pair of tungsten electrodes 110 having one end connected to one end of the foil 108 and having the other end disposed in the internal space 106, and one end connected to the other end of the foil 108 and the other end. A pair of outer guiding bars 112 are extended from the sealing portion 104. Further, a specified amount of mercury 114 and halogen (for example, bromine) are enclosed in the internal space 106.

When a predetermined high voltage is applied to the pair of guiding bars 112 provided in the lamp body 20, the glow discharge started between the pair of electrodes 110 provided in the internal space 106 of the arc tube portion 102 is converted into an arc discharge, and further via The mercury 114 evaporated/excited by the arc emits light (in the case of the present embodiment, mainly ultraviolet rays).

Returning to Fig. 2, the mirror 22 has a bowl-shaped reflecting surface 24 on its inner side surface. The reflecting surface 24 reflects a portion of the light from the lamp body 20, and the lamp body 20 is disposed such that the arc tube 102 is located inside the mirror 22. In the present embodiment, the reflecting surface 24 is specified by a paraboloid of revolution. The light-emitting point in the lamp body 20 (generally, the intermediate position of the pair of electrodes 110 of the internal space 106) coincides with the focus of the rotating paraboloid. Thereby, the light emitted from the light-emitting point of the lamp body 20 is reflected by the reflecting surface 24, and the light emitted from the light-emitting surface 25 of the mirror 22 becomes substantially parallel light. Of course, the shape of the reflecting surface 24 is not limited thereto, and may be a rotating paraboloid or another rotating surface, or may be a shape other than the rotating surface.

By the combination of the lamp body 20 and the mirror 22, the light radiated from the lamp body 20 is directed toward the front of the mirror 22 at a predetermined angle (hereinafter referred to as "aperture angle θ ₂ ") around the optical axis LCL. go ahead.

As shown in FIG. 4, the lamp set 11 has a longitudinal dimension V and a lateral dimension H. The longitudinal dimension V of the lamp set 11 refers to the reflection of the lamp 12 from the center of the uppermost segment of the lamp 12 in the vertical direction (more precisely, the reflecting surface 24 of the mirror 22) to the lowermost segment of the lamp 12 in the vertical direction. The distance of the mirror 22 (more precisely, it is the reflective surface 24 of the mirror 22). Further, the lateral dimension H of the lamp group 11 refers to the mirror 22 of the lamp 12 from the rightmost end in the horizontal direction (more precisely, this The distance from the center of the reflecting surface 24) of the mirror 22 to the center of the mirror 22 of the lamp 12 in the leftmost direction in the vertical direction (more precisely, the reflecting surface 24 of the mirror 22).

Returning to Fig. 1, the integrator 14 has an exit surface 28 for receiving the incident surface 26 of light from the plurality of lamps 12 and increasing the uniformity of the received light and then emitting the light. A plurality of flyeye lenses 30 are formed on the incident surface 26 and the exit surface 28, respectively.

As shown in FIG. 5, the integrator 14 has an integrator incident angle θ ₃ determined based on elements such as the shape of the fly-eye lens 30. A straight line G is formed by a focal point F of the fly-eye lens 30 on the central axis FCL of the center of the fly-eye lens 30 constituting the integrator 14 and a line connecting the outermost ends of the fly-eye lenses 30. The integrator incident angle θ ₃ at this time is defined as the angle formed by the straight line G and the central axis FCL. Further, the central axis CL of the integrator 14 and the central axis FCL of the fly-eye lens 30 are generally parallel to each other.

In the case where the angle from the light of the lamp 12 toward the entrance face 26 of the integrator 14 and the central axis CL of the integrator 14 is within the integrator angle of incidence θ ₃ , the light is taken from the integrator at a desired angle The exit surface 28 of the 14 is desirably emitted, and the exposure target X is exposed. In other words, the light that illuminates the incident surface 26 of the integrator 14 at an angle larger than the integrator incident angle θ ₃ cannot be efficiently emitted from the emitting surface 28, and thus becomes light that does not contribute to the exposure of the exposure target X.

Returning to Fig. 1, the concave mirror 16 is formed with a reflective concave surface 32 on the inner side thereof. The concave mirror 16 causes the light emitted from the integrator 14 to be reflected by the reflective concave surface 32 to form parallel light.

The irradiation surface 18 is a surface that receives the parallel light from the concave mirror 16, and is disposed in a direction substantially orthogonal to the parallel light. The exposure target X is placed on the irradiation surface 18. For example, a sensitizer is applied to the surface of the exposure target X. By irradiating the parallel light from the concave mirror 16 to a desired region of the exposure target X, a desired circuit pattern or the like is formed on the surface of the exposure target X.

In the present embodiment, the positional relationship between the lamp group 11 and the integrator 14 composed of the plurality of lamps 12 satisfies the following conditional expressions 1 and 2 (see FIG. 6).

Conditional formula 1: a≦tan θ ₁ × L × 2

Condition 2: θ _{1 -} θ ₂ = θ ₃

Here, a: the longitudinal dimension V and the lateral dimension H of the lamp group 11; L: the distance from the light exiting position S of the lamp 12 to the incident position R of the integrator 14; θ ₁ : the optical axis LCL and integral of each of the lamps 12 The maximum value of the angle θ formed by the central axis CL of the device 14; θ ₂ : the aperture angle of the light from each of the lamps 12; θ ₃ : the incident angle of the single fly-eye lens carried by the integrator.

Conventionally, in the case where the exposure device 10 uses the lamp group 11 composed of a plurality of lamps 12, if the lamp 12 is brought closer to the upper and lower ends or the left and right ends of the lamp group 11, the central axis CL of the integrator 14 is opposed to the lamp. When the angle at which the angle θ of the optical axis LCL of 12 is larger is considered in consideration of the arrangement angle of the lamp 12, it is considered that the number of the lamps 12 can be increased as much as possible in accordance with the amount of light required for exposure. That is, it is considered that the longitudinal dimension V and the lateral dimension H of the lamp group 11 can be increased as much as possible.

However, it is known that the angle θ formed by the optical axis LCL of the lamp 12 and the central axis CL of the integrator 14 becomes large due to the arrangement angle of the lamp 12, once the light from the lamp 12 and the central axis CL of the integrator 14 When the angle formed is greater than the integrator angle of incidence θ ₃ , then the light may not be an effective light for facilitating exposure.

For this point, the description is as follows. 7 is a graph showing the relationship between the total light amount of the exposure surface and the angle θ; wherein the horizontal axis is the angle θ formed by the central axis CL of the integrator 14 and the optical axis LCL of the lamp 12, and the vertical axis is the slave integrator 14 The emission surface 28 is efficiently emitted at each angle θ and contributes to the amount of light that is exposed by the exposure object X. Further, in the graph, the integrator incident angle θ ₃ is 6°, and the aperture angle θ ₂ of the lamp 12 is 2°.

When so implemented, although the angle θ is "zero" to "integrator incident angle θ ₃ - aperture angle θ ₂ " (i.e., between 0° and 4°), almost all of the light from the lamp 12 has Helps exposure, however, once the angle θ is greater than the "integrator angle of incidence θ ₃ - aperture angle θ ₂ " (ie, if greater than 4°), the amount of light that contributes to exposure is reduced. Moreover, once the angle θ becomes greater than the "integrator angle of incidence θ ₃ + aperture angle θ ₂ " (ie, becomes greater than 8°), then almost all of the light from the lamp 12 is not helpful for exposure. Benefited. In other words, if "θ ₃ + aperture angle θ ₂ ≧ angle θ", at least a part of the light emitted from the lamp 12 becomes exposure for the exposure target X.

On the premise that "θ ₃ = θ - θ ₂ " based on the above cognitive knowledge is satisfied, returning to FIG. 6 , the light-emitting position S of the lamp group 11 is set to the distance L from the incident position R of the integrator 14 , and the lamps are The maximum value among the angles θ formed by the optical axis LCL of 12 and the central axis CL of the integrator 14 is θ ₁ (normally, the value of the angle θ is the largest at the position farthest from the center of the lamp group 11 The lamp 12 (hereinafter referred to as "the farthest position lamp D").). That is, "θ ₃ = θ _{1 -} θ ₂ " (Condition 2).

Next, the longitudinal dimension V and the lateral dimension H of the lamp group 11 are set within the size a calculated from "tan θ ₁ × L × 2". In other words, "a≦tan θ ₁ × L × 2" is set (Conditional Expression 1). Thereby, at least a part of the light emitted from the farthest position lamp D (generally) of the maximum value θ ₁ among the angles θ formed by the optical axis LCL of each of the lamps 12 and the central axis CL of the integrator 14 is This is incident on the integrator 14 within the integrator angle of incidence θ ₃ and further contributes to the exposure. In other words, even light from the lamp 12 disposed outside the size a does not become useless light that does not contribute to exposure.

Further, the light-emitting position S of the lamp group 11 is a line J which is connected to the center of the mirror 22 in the pair of outermost lamps 12 constituting the lamp group 11, and intersects with the central axis CL of the integrator 14. s position. Further, the incident position R of the integrator 14 is a position that intersects with the vertex of each of the fly-eye lenses 30 constituting the integrator 14 and intersects with the central axis CL of the integrator 14. Further, the height A of the integrator 14 is sufficiently smaller than the dimension a or the distance L (i.e., a>>A, and, L>>A).

Therefore, the exposure apparatus 10 according to the present embodiment can avoid occurrence of the case where the lamp 12 having all of the emitted light becomes useless light that does not contribute to the exposure, so that all the lamps 12 can be made Helps with exposure.

(Modification)

(1) The separation distance of the pair of electrodes 110 (that is, the "electrode interval" of the lamp 12) is preferably set to 0.8 mm or more and 1.5 mm or less. Further, the electrode spacing is related to the aperture angle θ _{2 of the} lamp 12. Once the electrode spacing is narrowed, the aperture angle θ _{2 of} the lamp 12 becomes smaller. Conversely, once the electrode spacing is widened, the aperture angle θ _{2 of} the lamp 12 becomes larger. Therefore, it is preferable to change the electrode spacing of each of the lamps 12 in view of the arrangement state of the lamps 12 in the lamp group 11, so that the above conditional expressions (1) and (2) are satisfied.

(2) In the exposure apparatus 10 of the above-described embodiment, the convex lens 50 may be further added as shown in FIGS. 8 and 9. The convex lens 50 is disposed on the surface of the integrator 14 facing the lamp group 11, that is, on the incident surface 26 side. The convex lens 50 is preferably disposed at a position including a lens center 52 and a plane in contact with the apex of each of the fly-eye lenses 30 as shown in the figure, but may be disposed at a position slightly apart from the plane. Still further, it is preferable to make the position of the lens center 52 and the incident position R of the integrator 14 coincide with each other.

By providing the convex lens 50 as described above, the light from each of the lamps 12 is refracted via the convex lens 50 so that the angle formed by the central axis CL of the integrator 14 is reduced. In other words, the light that contributes to the exposure of the exposure object X, that is, the light incident on the incident surface 26 of the integrator 14 at an angle θ ₁ formed with the central axis CL, is as long as θ ₁ + α ("α" is a convex lens The angle determined by 50.) may be incident on the convex lens 50. As a result, the value a of the longitudinal dimension V and the lateral dimension H of the lamp group 11 can be made larger (=a+β), and more lamps 12 can be included in the lamp group 11, and thus it is possible to increase Helps to expose the exposure light of the object X. Therefore, it is preferable to change the curvature of the convex lens 50 as needed in view of the arrangement state of the lamp 12 in the lamp group 11, so that it satisfies the above conditional expressions (1) and (2).

(3) Unlike the above modification (2), the exposure device 10 may further include the lamp front lens 60 as shown in FIG. The lamp front lens 60 is disposed on the side of the lamp 12 facing the integrator 14, that is, on the side of the light exit surface 25. The lamp front lens 60 has a function of reducing the diffusion of light from the lamp 12. As shown, a lamp front lens 60 may be provided for each of the lamps 12, or one lamp front lens 60 may be provided for one lamp group 11. Further, as long as the lamp front lens 60 can reduce the diffusion of light from the lamp 12 as described above, a convex lens, a Fresnel lens, or another type of lens can be used.

By providing the lamp front lens 60 as described above, the light from each of the lamps 12 is refracted via the lamp front lens 60 so that the angle formed by the central axis CL of the integrator 14 is reduced. In other words, in the case where the value "a" of the longitudinal dimension V and the lateral dimension H of the lamp group 11 are the same, it becomes possible to use the lamp 12 having a larger aperture angle θ ₂ . Conversely, in the case of using the lamp 12 having the same aperture angle θ ₂ , the value a of the longitudinal dimension V and the lateral dimension H of the lamp group 11 can be made larger (= a + β) as illustrated, and The lamp group 11 is made to include more lamps 12, and it is possible to increase the light that contributes to the exposure of the exposure object X. Therefore, in view of the arrangement state of the lamps 12 in the lamp group 11, the curvature of the lamp front lens 60 is changed as needed, so that the above conditional expressions (1) and (2) are satisfied.

All the points of the embodiments disclosed herein are to be considered as illustrative and not restrictive. The scope of the present invention is defined by the scope of the claims, and is intended to be

11‧‧‧Lights

12‧‧‧ lights

14‧‧‧ integrator

26‧‧‧Incoming surface

28‧‧‧ shot surface

30‧‧‧Future eye lens

θ ₁ ‧‧‧ (integrator) effective angle of incidence

θ ₂ ‧‧‧ (the light of each lamp) aperture angle

CL‧‧‧ (integrator) central axis

LCL‧‧‧ (light) optical axis

a‧‧‧Digital and transverse dimensions of the light group

The distance from the light exit surface of the lamp 12 to the entrance surface 26 of the integrator 14

J‧‧‧ Straight line

S‧‧‧ (light group) light exit position

R‧‧‧ (integrator) incident position

D‧‧‧Lights 12 arranged farthest from the center of the light group 11

A‧‧‧ Height of integrator 14

Claims (8)

An exposure apparatus including: a lamp group including a plurality of lamps; and an integrator for receiving light from the plurality of lamps to improve uniformity of the light; and satisfying Conditional Formulas 1 and 2 below : Conditional expression 1: a≦tan θ ₁ × L × 2 Conditional expression 2: θ _{1 -} θ ₂ = θ ₃ However, where a: the longitudinal dimension and the lateral dimension of the lamp group; L: from the light exit position of the lamp group to the integral The distance from the incident position of the device; θ ₁ : the maximum of the angles formed by the optical axis of each lamp and the central axis of the integrator; θ ₂ : the aperture angle of the light from each lamp; θ ₃ : carried by the integrator The angle of incidence of a single fly-eye lens. The exposure apparatus according to claim 1, wherein the lamp is a discharge lamp, and an electrode interval of the discharge lamp is 0.8 mm or more and 1.5 mm or less. The exposure apparatus according to claim 1, wherein the exposure apparatus further includes a convex lens that is disposed on a surface side of the integrator facing the lamp group. The exposure apparatus according to claim 1, wherein the exposure apparatus further includes a lamp front lens, wherein the lamp front lens is disposed on a surface side of the lamp facing the integrator, and is for reducing the aforementioned light from the lamp The spread of light. A design method of an exposure apparatus using: a lamp group composed of a plurality of lamps; and an integrator for receiving light from the plurality of lamps and improving uniformity of the light, and satisfying the following conditional expression 1 and 2, Conditional Formula 1: a ≦ tan θ ₁ × L × 2 Conditional Formula 2: θ _{1 -} θ ₂ = θ ₃ However, where a: the longitudinal dimension and the lateral dimension of the lamp group; L: the light from the lamp group The distance from the position to the incident position of the integrator; θ ₁ : the maximum of the angles formed by the optical axis of each lamp and the central axis of the integrator; θ ₂ : the aperture angle of the light from each lamp; θ ₃ : integrator The angle of incidence of a single fly-eye lens carried. The method of designing an exposure apparatus according to claim 5, wherein the lamp is a discharge lamp, and an electrode interval of the discharge lamp is 0.8 mm or more and 1.5 mm or less. The method of designing an exposure apparatus according to claim 5, wherein the integrator includes a convex lens disposed on a surface side facing the light group. The method of designing an exposure apparatus according to claim 5, wherein a lamp front lens is further used, which is disposed on a surface side of the lamp facing the integrator, and serves to reduce diffusion of the light from the lamp.