CN111954850A

CN111954850A - Method, optical component and exposure system for exposing a non-planar object

Info

Publication number: CN111954850A
Application number: CN201980012383.5A
Authority: CN
Inventors: R·帕根
Original assignee: Mihua Technology Co ltd
Current assignee: Mihua Technology Co ltd
Priority date: 2018-02-09
Filing date: 2019-01-11
Publication date: 2020-11-17
Anticipated expiration: 2039-01-11
Also published as: DE102018102943B4; CN111954850B; WO2019154582A1; DE102018102943A1; KR20200118070A

Abstract

The invention relates to a method for exposing a non-planar object (14), wherein an optical component (41) is arranged on the non-planar object (14) to be exposed, wherein the contour (43, 45) of the optical component is formed in such a way that a constant optical path length is generated during a single exposure operation between the light output of a processing head (16) or an exposure source (20) for exposing the non-planar object (14) and each point on the surface (33) of the non-planar object (14) to be exposed. (see fig. 4).

Description

Method, optical component and exposure system for exposing a non-planar object

The present invention relates to a method for exposing a non-planar object, an optical member and an exposure system having the optical member.

Direct exposure systems are used to expose objects to light in order to apply a photolithographic structure to them. The main task of such exposure systems is to accurately irradiate structured light onto the object to be exposed. However, direct exposure systems have limited depth of field at high resolution. For this reason, the structures to be exposed, which have different contour heights, must be exposed one after the other in different process steps, whereby the exposure system must be adjusted to a new height between exposure processes. This is extremely time-consuming and may lead to quality problems due to the composition of the structures created in the different process steps, especially in the case of fine structures.

The object of the invention is to provide a method for exposing a non-planar object, i.e. an object having a surface to be exposed with different contour heights, as well as an optical component and an exposure system having the optical component which enable a simplified exposure of the non-planar object.

This object is achieved according to the invention by the features of the independent patent claims. Advantageous features are the subject of the dependent claims.

In this method for exposing a non-planar object, optical components are arranged on the non-planar surface of the object to be exposed, forming the contour of the object in such a way that a constant optical path length is generated during a single exposure process between the light output of a processing head or exposure source used to expose the non-planar object and each point on the surface of the non-planar object to be exposed.

Since the shape of the optical component is adapted to the contour of the object to be exposed, the exposure can be carried out in a single step. This means that the exposure system does not have to be readjusted each time there is a change in height in the profile of the surface of the object. The surface of the non-planar object may be exposed in a single exposure process. This saves time and money and reduces the probability of quality problems that may occur when exposing parts of the object in different steps.

Furthermore, objects in one clamp (chucking) or one position on the table or the support of the exposure system may result in increased accuracy in exposing the surface of a non-flat object.

Preferably, the optical component having the first non-planar profile and the opposing second non-planar profile is placed such that the first non-planar profile is on a non-planar surface of the object to be exposed, such that the first non-planar profile is directly on the surface of the object. This results in independent alignment of the optical components to the non-planar optical object. Furthermore, additional light refraction of the light beam is prevented at the transition from the first non-planar profile to the surface of the non-planar object to be exposed.

In this method, the second non-planar profile of the optical component of the exposure beam facing the processing head or the illumination source may be shaped stepwise at least in sections. In this configuration of the second non-planar profile of the optical component, the depth of field of the exposure source is sequentially controlled and adapted to the steps during lateral movement of the exposure source relative to the non-planar object to be exposed.

Alternatively, it may be assumed that, in the case of a second non-planar profile of the optical component associated with the exposure source and assumed to be step-free, the lateral movement of the exposure source relative to the non-planar object to be exposed continuously adjusts the depth of field of the exposure source for the course of the profile (course). Preferably, this is done by pre-compensating for optical distortion by modifying the exposure data. Thus, distortion of the occurring light beam can be minimized.

The task underlying the invention is solved by an optical exposure system comprising an exposure source which emits an exposure beam in the direction of a support, wherein a non-planar object to be exposed and an optical component arranged on the non-planar object are situated on the support, and a first non-planar contour of the optical component facing the non-planar object and resting thereon is adapted to the shape of the non-planar object to be exposed, and a second non-planar contour of the optical component facing the exposure source or the processing head emitting the exposure beam is formed in such a way that a constant optical path length is provided between each point on the surface of the non-planar object to be exposed and the light output of the processing head or the exposure source during a single exposure operation.

Thus, in case the optical component is adapted to the contour of the surface of the object to be exposed, the exposure may be performed in a single process step. This means that the exposure system does not have to be readjusted each time the height of the contour of the object to be exposed changes.

Furthermore, it is assumed that the exposure source can be moved in different directions of travel at the same distance from a virtual plane passing through the highest point of the optical component, so that the exposure beams emitted by the exposure source or the processing head impinge parallel to one another and substantially perpendicularly on the virtual plane. Since the optical component is formed in such a way that it has an appropriate shape for each area of the object to be exposed in order to avoid height adjustment of the exposure system, i.e. the exposure system can be moved at a predetermined constant distance from the object, the exposure can be performed more quickly and in one operation step.

The task underlying the present invention is further solved by an optical component, in particular for use in an optical exposure system according to the above described embodiments, comprising a body having a first non-planar profile adapted to a surface of a non-planar object to be exposed and having a second non-planar profile opposite to the first non-planar profile and forming an entrance side for an exposure beam, and in that the first and second non-planar profiles are adapted to set a constant optical path length between any point on the surface of the non-planar object to be exposed and a light output of a processing head or an exposure source during one single exposure operation. This optical component makes it possible to move the exposure source or the processing head at a constant distance for guiding the exposure beam, i.e. without requiring height adjustment, even if the object to be exposed is not flat.

Preferably, the contour of the optical component facing the exposure source or the processing head has a stepped or step-free surface, at least in sections thereof.

Advantageously, the first and second non-planar profiles are aligned with a common axis of the body, whereby in a body made of a material having a refractive index n =2, the first and second non-planar profiles are aligned mirror-symmetrically with respect to this axis.

Alternatively, it may be assumed that the first and second non-planar profiles are aligned opposite to each other with respect to a common axis of the bodies, wherein the second non-planar profile or the profile associated with the exposure source has a vertical distortion with respect to the first lower profile by an amount of 1/(n-1) in case the bodies of the optical component are made of a material having a refractive index n < 2 (e.g. n =1.4 or n = 1.5). This may in turn allow adaptation to a constant optical path length.

Furthermore, it is assumed that the optical component is made of a plastic material, in particular a transparent plastic material, for example acrylic, and is produced by milling and/or grinding or by casting.

The invention and other advantageous forms of carrying out and further training the invention are described and explained in more detail below on the basis of examples shown in the drawings. The features to be taken from the description and the drawings may, in accordance with the invention, be applied separately or in any combination. Shown here are:

figure 1 is a perspective view of an exposure system,

figure 2 is a perspective view of a non-planar object to be exposed,

FIG. 3 is a perspective view of an optical component adapted to a non-planar object to be exposed; and

fig. 4 is a schematic side view of an object to be exposed during an exposure process.

Fig. 1 shows an example of an exposure system 11. This exposure system 11 comprises a housing 13 with a machine base frame on which a support 12 is movably mounted. The support 12 is used to hold an object 14 to be exposed. The object 14 may be placed on the support 12 or held in a clamp. On the operator side, the housing 13 is provided with an opening 15, through which opening 15 the support 12 can be at least partially removed for placing the object 14 thereon. In the same way, the at least one object 14 can be removed from the support 12 or removed from the housing 13. The exposure system 11 includes at least one processing head 16. An exposure beam 17 from an exposure source 20 is directed onto the object 14 to be exposed by an exposure head 16. The treatment head 16 is preferably moved on a

linear axis system

18, 19. For example, the guide axis 19 may be moved in the Y direction to move the guide axis 18, whereby the at least one treatment head 16 may be moved along the guide axis 18. The

linear axis system

18, 19 and the at least one machining head 16 are moved under computer program control with a control 27. The control 27 preferably has a user interface 28 and, if necessary, a display. This allows individual program steps and process sequences to be entered and/or initiated.

Fig. 2 shows the object 14 to be exposed in perspective. The shape and geometry of this non-planar object 14 to be exposed is merely exemplary. Such an object 14 may be a housing, enclosure, casing of a device, or one or more components of a device, etc. This object 14 comprises a body 31, which body 31 has for example an outer surface 32 with a curved surface 33. This curved surface 33 may be limited by two

end surfaces

34, 35, on which the body 31 rests, for example, on a support. The curvature of the curved surface 33 may be variously oriented and may also include ridges and valleys. The non-planar object 14 may have concave and/or convex curved outer sides, as well as additional contoured or stepped shaped ridges or valleys.

The surface 33 of the object 14 may be exposed or treated with an exposure beam 17. For example, if the processing head 16 is moved in the X-direction and the exposure beam 17 traverses the surface 33 of the object 14 in the movement direction V1, as shown in fig. 2, the distance of the optical path to the processing head 16 continuously changes due to the curvature of the surface 33 on the outer side 32 or the non-uniform object 14. This would require adjustment in the height of the exposure system, since the direct exposure system has a limited depth of field at high resolution.

To expose such a non-planar object 14 with a direct exposure system, an optical component 41, for example, as shown in fig. 3, is used. The optical component 41 comprises a body 42 having a first non-planar profile 43. This first non-planar profile 43 is adapted in its course to the surface 33 of the outer side 32 of the non-planar object 14 to be exposed. This first contour 43 extends to the

front side

34, 35 of the object 14 to be exposed and preferably has a contact surface 44, by means of which contact surface 44 the optical component 41 can rest on the support 12. Alternatively, such a contact surface 44 may also be omitted. The optical component 41 must be provided to rest on the object 14 in a self-retaining manner.

The optical component 41 has a second non-planar profile 45 opposite the first non-planar profile 43. The design of this second non-planar profile 45 is adapted to the design of the first non-planar profile 43.

The optical member 41 is made of a material transparent to the exposure beam 16. Preferably, a transparent material, in particular a transparent plastic, is provided.

Such an optical component 41 makes it possible to expose the non-planar object 14 in one single exposure step. In particular, in a direct exposure system, this optical component 41 allows exposure of an object 14 having a non-planar surface 33 of the outer side 32.

To expose the outer side 32 of the non-planar object 14 in the exposure system 11, an optical component 41 is placed on the outer side 32 of the object 14. The first contour 43 of the optical component 41 is designed in such a way that it lies directly on the outer side 32 and follows the surface 33. The shape of the second non-planar profile 45 of the optical component 41 depends on the shape of the surface 33 to be exposed and the material from which the optical component is formed, so that the treatment of the surface 33 of the object 14 is carried out in one exposure step. This performance in one exposure step requires that a constant optical path length be created between each point on the surface 33 of the non-planar object 14 to be exposed and the light output of the processing head 16. This means that the shape and material of the optical component 41 used compensate the height in order to create a quasi-fictional (squarification) exposure plane L. This means that no readjustment of the exposure system is necessary.

In preparation for treating the surface 33 of the object 14, the optical member 41 is placed on top. This is shown in fig. 4. The first non-planar profile 43 lies flush with the surface 33 of the object 14. Furthermore, the optical component 41 may comprise at least two

front sides

34, 35 for accurate fixation and positioning of the object 14.

During exposure, the exposure beam 17 passes through the optical component 41 and strikes the surface 33 of the object 14 to expose this surface 33.

If a material with an index of refraction n =2 is used for the optical component 41, the second non-planar profile 45 may be a mirror image of the first non-planar profile 43 about the longitudinal central axis 46.

Typically, the materials used (such as acrylic) have different refractive indices. This refractive index of acrylic is for example in the range of n =1.4 or n =1.5, so the second non-planar profile 45 has to be adapted to the optical component 41 with respect to the first non-planar profile 43. The second non-planar profile 45 of the component 41 is calculated in such a way that the height of the upper edge from the deepest point of the second profile increases by an amount 1/(1-n), where n denotes the refractive index of the material used for the optical component 41. Thus, if the refractive index is 1.5 and a height difference of 3mm with respect to a flat surface (e.g. support 12) has to be compensated for, the total height at least at certain areas of the optical component 41 is 10mm, as explained below.

As shown in fig. 4, the thickness X of the optical component 2 at the highest point of the non-planar object 14 is the same over the entire component. The second profile 45 of the optical component 41 is a vertical enlargement of the object profile (profile) by an amount 1/(n-1) compared to the first profile 43. Since the scan function for exposure is a linear distance function with optical path component = X/n, X can be assumed to be 0. Thus, X is ignored or, for simplicity, the thickness or intensity of the optical component 41 at the highest point of the object 14 is assumed to be X = 0. The maximum height of the non-planar object 14, measured from the point furthest from the support 12 to the point closest to the support 12, is referred to as the thickness D. In order to obtain a constant optical path length for any refractive index n, according to the present application, a multiplier m is sought by which the optical component 41 can be dimensioned (dimension).

Due to the fact that the optical path length D X at the highest point, m of the optical component 41 in air (we have assumed X =0 mm), is the same as the optical path length at which the object 14 has a height D =0mm, as shown in fig. 4, the following applies:

(D x m)/1 = (D x m + D)/n (1)

wherein the refractive index of air is n =1.

The result is therefore:

m = (m+1)/n (2)

and using it:

n = (m+1)/m = 1+1/m (3)

so n-1=1/m or m =1/(n-1) follows.

In the case of materials with a refractive index n =1.5 are generally used and a maximum object height D =3mm, the minimum total height of the component is thus D/(1.5-1) + D =9mm, again assuming X =0 for the sake of simplicity.

If X =1mm is assumed to be the minimum thickness of the optical component 41, this results in a total physical height of the optical component 41 of 10 mm.

To determine the thickness of the optical component 41, a calculation for D1 is shown below, which in this example is equal to 2mm (at a maximum object height of 3mm and a refractive index of 1.5).

Here, D =2mm is used in equation D/(1.5-1) + D. The results were: 2mm/(1.5-1) +2mm = 6 mm. If again X =1mm is assumed to be the minimum thickness of optic 14, this results in a total physical height of optic 14 of 7 mm.

The optical height above the entire optical component 41 is always 10mm/1.5, i.e. about 6.7 mm.

For D =0, i.e. at the highest point of the object 14, the results are as follows: the light path until it strikes the object is 7mm, i.e. 10mm-3mm (no light passes). Among these, X =1mm has a refractive index of 1.5, and the remaining optical path of 6mm has a refractive index of 1, because light passes through air here. This results in: 1mm/1.5+6mm/1= approximately 6.7 mm.

The same principle should apply to every point on the upper contour 45 of the optical component 41. Thus, for example, at point D1=2mm, it can be seen that the total height 7mm of the optical component 41 with refractive index 1.5 and the remaining height of 2mm (in air) with refractive index 1 (the distance of the object 14 from the support 12-here 1 mm-is to be subtracted from the remaining total height, i.e. 10mm-7mm-1mm =2 mm), add together to give: 7mm/1.5+2mm/1= approximately 6.7 mm.

The optical component 41 is thus formed in such a way that, in the case of a non-planar object 14 to which a photomechanical structure is to be applied, it adjusts the optical path to the object 14 in such a way that no readjustment of the exposure system 3 is necessary. The optical component 41 can be produced for most varying shapes of the object 14, i.e. also objects 14 that are bent several times in one or more directions, etc. Thus, the exposure process can be carried out without interruption. This eliminates a source of error, reduces cost and saves time.

The second non-planar profile 45 of the optical component 41 may be formed as a step-free surface. The surface thus exhibits a continuous change.

With a stepless design of the surface, it is preferably intended that depending on the refraction angle, compensation or tracking of the exposure beam takes place during exposure. This is also known as flyback (flyback). Here, the optical distortion of the image is pre-compensated by modifying the exposure data to include refraction, or by taking into account the corresponding extension of the optical path when designing the second non-planar profile 45 of the optical component 41.

Alternatively, the second non-planar profile 45 may also be designed as a stepped surface with a single step S. Each step S represents a different depth of field. A sequence of exposures of the non-planar object 14 is made along the corresponding contour lines. These steps S may be created by, for example, milling. In this way, distortion of the exposure beam 18 may be minimized. For the design of the step S, it is preferable to provide a width at which the depth of field of the exposure system is not exceeded.

Claims

1. Method for exposing a non-planar object (14), characterized by: an optical component (41) is arranged on the non-planar object (14) to be exposed, the contour (43, 45) of which is formed in such a way that a constant optical path length is generated between the light output of a processing head (16) or exposure source (20) for exposing the non-planar object (14) and each point on the surface (33) of the non-planar object (14) to be exposed during a single exposure operation.

2. The method of claim 1, wherein: an optical component (41) having a first non-planar profile (43) and an opposing second non-planar profile (45) is placed such that the first non-planar profile (43) is on a non-planar surface (33) of an object (14) to be exposed such that the first non-planar profile (43) is positioned directly adjacent to the surface (33) of the object (14).

3. The method according to claim 1 or 2, characterized in that: controlling a lateral movement of the exposure source (20) or the processing head (16) relative to the non-planar object (14) to be exposed, with the second non-planar profile (45) of the optical component (41) facing the exposure source (20) or the processing head (16) and being formed at least in sections in a step-like manner, wherein a sequential depth of field suitable for the exposure of the steps (S) is controlled.

4. The method according to claim 1 or 2, characterized in that: controlling a continuous lateral movement of the exposure source (20) or the processing head (16) relative to the non-planar object (14) to be exposed, the exposure being modified by pre-compensation, with the second non-planar profile (45) of the optical component (41) facing the exposure source (20) or the processing head (16) and having at least one continuously formed surface 20 of the second non-planar profile (45).

5. Optical exposure system (11) having an exposure source (20) emitting an exposure beam (17) in the direction of a support (12), characterized in that: the non-planar object (14) to be exposed is provided on a support (12), and an optical component (41) is arranged on the non-planar object (14) to be exposed, wherein a first non-planar contour (43) of the optical component (41) facing the object (14) and resting on the surface (33) of the object (14) is adapted to the shape of the surface (33) of the object (14) to be exposed, and a second non-planar contour (45) of the optical component (41) opposite to the first non-planar contour (43) is formed in such a way that during a single exposure operation there is a constant optical path length between the light output of the processing head (16) or exposure source (20) and each point on the surface (33) of the non-planar object (14) to be exposed.

6. The optical exposure system (11) according to claim 5, characterized in that: the processing head (20) is movable in the X and/or Y direction at the same distance from a virtual plane L through the highest point of the optical component (41) such that the exposure beam (17) impinges substantially perpendicularly on the plane L.

7. An optical component (41), in particular for use in an optical exposure system (11) according to claim 5 or 6, wherein the optical component (41) comprises a body (42), the body (42) having a first non-planar profile (43) adapted to the surface (33) of the non-planar object (14) to be exposed and having a second non-planar profile (45) opposite the first non-planar profile (43) and forming an entrance side for an exposure beam (17), and wherein the first and second non-planar profiles (43, 45) are adapted to set a constant optical path length between the light output of the processing head (16) or the exposure source (20) and each point on the surface (33) of the non-planar object (14) to be exposed during a single exposure operation.

8. The optical component (41) of claim 7, wherein: the second non-planar contour (45) of the optical component (41) is formed at least in sections with a step (S) in a stepped manner or continuously.

9. The optical component (41) according to claim 6 or 7, characterized in that: the first and second non-planar profiles (43, 45) are aligned opposite to each other with respect to a common longitudinal axis (46), wherein in the body (42) of the optical component (41) made of a material having a refractive index n =2.0, the first and second non-planar profiles (43, 45) are aligned mirror-symmetrically with respect to the longitudinal axis (46).

10. The optical component (41) according to claim 7 or 8, characterized in that: the first and second profiles (43, 45) are aligned opposite each other, wherein in the body (42) of the optical component (41) made of a material having a refractive index n < 2, in particular n =1.4 or n =1.5, the second non-planar profile (45) has a vertical enlargement relative to the first non-planar profile (43) by an amount 1/(n-1).

11. The optical component (41) according to claims 7 to 10, characterized in that: the body (42) is constructed of a material that is mostly transparent or translucent to the beam (17), in particular, to the laser light.

12. Optical component (41) according to one of claims 7 to 11, characterized in that: the body (42) is made of plastic, in particular acrylic.