Method and apparatus for exposing a photosensitive coating layer

Abstract

A method and apparatus for exposing a photosensitive coating layer. [Solution] A method for exposing a photosensitive coating layer (3) having at least one photosensitive first region (3a) and a photosensitive second region (3b), wherein the first region (3a) reacts to photons of a first wavelength, the second region (3b) reacts to photons of a second wavelength, the first wavelength being different from the second wavelength, and the method comprises the steps of - exposing the coating layer (3) with photons of the first wavelength, and - exposing the coating layer (3) with photons of the second wavelength, particularly a sequence of steps.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for exposing a photosensitive coating layer.

[0002] Photolithography is one of the most important methods for patterning materials in the semiconductor industry. In the prior art, photolithography is mainly carried out using a mask.

[0003] However, mask fabrication is also the biggest problem in mask-based photolithography. Masks have to be formed by an extremely expensive and time-consuming fabrication method. In this case, electron beam lithography is used. Furthermore, in order to fabricate complex and functional components, multiple masks have to be fabricated. In this case, it is not uncommon for the cost for fabricating all the masks for just one microchip to be on the order of several million euros.

[0004] Therefore, in recent years, alternative methods have been developed in the prior art. In this alternative method, instead of the substrate being exposed over the entire surface, it is only partially exposed by a digitally controlled scan, for example by a switchable array consisting of mirrors. The mirrors of a so-called digital micromirror unit (DMU), which is a mirror array, can be individually programmed, especially at high frequencies, thereby enabling a precisely spot-responsive and arbitrarily patternable irradiation to the sections to be exposed. At the same time, a relative movement between the substrate and the optical system including the DMU is carried out. Thereby, exposure of the entire substrate surface becomes possible. The prior art is known based on International Publication No. WO 2018 / 1 13917, International Publication No. WO 2018 / 113918 and International Publication No. WO 2019 / 242840.

[0005] By using DMD, a photolithography layer can be exposed in a predetermined pattern, or so-called layout. Indirect or direct chemical reactions occur in the photolithography layer at all points where it is impacted by photons of a well-defined wavelength. The so-called layout is then enhanced by subsequent method steps, particularly the development step.

[0006] In this disclosure, DMDs are always referred to as examples. However, instead of DMDs, general elements, particularly those for transmissive patterning, may be used. Transmissive optical elements are particularly important for steppers. In transmissive optical elements, unlike DMDs, spatially resolved patterning is achieved not by mirrors, but in particular by switchable apertures. The exact embodiments of such elements are not described in detail herein. Instead, DMDs are described as exemplary optical elements for programmable spatially resolved exposure.

[0007] By the method described above, it is now possible to form various 2D patterns, that is, patterns within a single plane or patterns in individual layers with varying heights, for example, as the uppermost layer in a pattern having various topographic (2.5D) characteristics.

[0008] In particular, complex geometric shapes that vary with respect to the direction of light, especially 2.5D or 3D pattern structures with concave hollow chambers covered on the upper side, cannot be fabricated in a single exposure process using prior art apparatus and methods.

[0009] By repeatedly using known methods, 2.5D and 3D patterns can be fabricated with great success. Therefore, a first layer can be deposited onto a substrate, exposed after image positioning, then developed, at which point the substrate can be chemically strengthened or dissolved depending on the exposure and polarity of the resist. The substrate can then be covered with a new subsequent layer, exposed again, and developed. These steps can be repeated at any frequency for a corresponding number of desired layers and thus the stacked layout.

[0010] It is clear that all of the method steps described above must be performed for the development of each layer. This results in an extremely time-consuming and costly process. Furthermore, each additional method step increases the probability of defects of any conceivable type. In particular, the correct lateral positioning during exposure is a defect-sensitive step. This step leads to an accumulation of quality losses.

[0011] Therefore, the object of the present invention is to eliminate or significantly reduce the drawbacks of the prior art. In particular, the present invention aims to make exposure faster and easier to perform and to reduce all kinds of defects.

[0012] This problem is addressed by the subject matter of each independent claim. Advantageous improved forms of the invention are described in the dependent claims. The scope of the invention also includes all combinations of at least two of the features described in the specification, claims, and / or drawings. In the numerical ranges described, numerical values ​​within the stated limits are also considered disclosed as limit values ​​and can be claimed in any combination.

[0013] The present invention relates to a method for exposing a photosensitive coating layer, wherein the coating layer has at least one first photosensitive region and a second photosensitive region, the first region responding to photons of a first wavelength, and the second region, particularly one superimposed on the first region, responding to photons of a second wavelength, the first wavelength being different from the second wavelength, and the method is as follows: - The coating layer is exposed with photons of the first wavelength, - Expose the coating layer with photons of a second wavelength. This relates to a method having steps, particularly a sequence.

[0014] In the following text, the photosensitive area may sometimes be referred to simply as the "area."

[0015] The present invention further relates to an apparatus for exposing a photosensitive coating layer, wherein the coating layer has at least one first photosensitive region and a second photosensitive region, the first photosensitive region reacts to photons of a first wavelength, the second photosensitive region reacts to photons of a second wavelength, the first wavelength is different from the second wavelength, and the apparatus includes a radiation device that exposes the coating layer with photons of the first wavelength and the coating layer with photons of the second wavelength.

[0016] The present invention further relates to articles produced by the method and / or apparatus according to the present invention.

[0017] The essence of this invention lies in eliminating the need for individual focusing of photons on each photosensitive region, because both regions are typically coated with very thin layers that are in close proximity to each other, within the depth of field of the projection. Photons of each wavelength can advantageously pass through the photosensitive coating layer, but only in regions where the material reacts to photons of corresponding wavelengths, thus generating photochemical reactions.

[0018] Preferably, the coating layer is exposed by a dynamically controllable device, particularly a digital micromirror unit, or the device has a dynamically controllable device, particularly a digital micromirror unit, for exposing the coating layer.

[0019] Preferably, the coating layer is further exposed through at least one mask, or the apparatus has at least one mask for exposing the coating layer.

[0020] Preferably, exposure of the coating layer with photons of a first wavelength causes a photochemical reaction only in the first region, and exposure of the coating layer with photons of a second wavelength causes a photochemical reaction only in the second region.

[0021] Preferably, the coating layer is further specified to be exposed or exposable in a spatially resolved and / or point-like manner, particularly using a beam of light.

[0022] Preferably, the coating layer is further specified to be exposed by an individually controllable photon source, and the wavelength and / or dose of the photons are or can be adjusted.

[0023] Preferably, the coating layer is further specified to be exposed by adjusting a filter positioned in front of a broadband photon source, thereby adjusting or being adjustable the wavelength and / or dose of the photons.

[0024] Preferably, it has been identified that different depth ranges of the coating layer react in succession.

[0025] Preferably, the coating layer is further specified to have sensitivity to photons of the same wavelength, which varies across the thickness of the coating layer.

[0026] Preferably, the coating layer is further specified as a single layer. Each different region is a different deposition layer having different photosensitivity intensities for different wavelengths of different intensities or for equal wavelengths. It is also possible that each different deposition layer is sensitive to irradiation intensity, i.e., strength, rather than to wavelength.

[0027] However, more preferably, it is specified that the first region is formed as the first layer and the second region is formed as the second layer on the first layer. Of course, optionally a plurality of further layers may be applied which form optionally a plurality of further regions which are processed together in a single common exposure and development step.

[0028] Preferably, furthermore, it is specified that the coating layer is movable relative to the radiation device. In particular, a movable holder is provided for moving the coating layer relative to the radiation device. The coating layer may be located on a substrate. And this substrate is located on a substrate holder. Preferably, this substrate holder is formed movably for moving the substrate provided with the coating layer relative to the radiation device.

[0029] The present invention particularly describes a method and an apparatus for maskless 2.5D or 3D exposure of a coating layer or a layer sequence having at least two photosensitive layers overlapping each other or at least two photosensitive layers located at different depths. In the following text, this 2.5D or 3D exposure is also referred to as spatial exposure in order to distinguish it from 2D exposure, i.e., exposure in a single plane. In particular, spatial exposure means an exposure by which a 2.5D or 3D pattern can be directly formed in a single exposure process. The exposure process means the set of all method steps between the loading of the substrate onto the apparatus and the unloading of the substrate.

[0030] The apparatus according to the present invention and the method according to the present invention have a plurality of advantages as compared with the prior art.

[0031] One advantage over the prior art is that, based on the omission of multiple positioning and intermediate processing steps, it is possible to carry out spatial exposure at a very high speed and at the same time with high accuracy. In particular, it is possible to dispense with multiple exposures with individual masks which have to be aligned before each exposure step, multiple coatings and multiple development steps. This advantage according to the present invention particularly achieves an improvement in throughput.

[0032] A further advantage is the significant improvement in the accuracy of the layout in each layer, because the alignment errors that occur when performing multiple individual exposures based on mask alignment are eliminated.

[0033] A further advantage is that the patterning depth can be increased through the depth of field and the chemical properties of the resist. Patterning depth refers to the region within the coating layer where chemical reactions occur due to photon bombardment.

[0034] In prior art, the optical elements for exposure must be designed such that the photons used for exposure are focused on the focal plane, or that the positioning of the photosensitive region is performed in the near field of the mask using the shadowing principle (Schattenwurfprinzip).

[0035] According to the present invention, advantageously, focusing light on individual photosensitive regions can be made unnecessary, or performed simultaneously within the depth of field of the projection, or by a fixed focal plane distance corresponding to the wavelength set in the instrument. Each photon of a particular wavelength can advantageously pass through the photosensitive coating layer, but only in regions where the material reacts to photons of the corresponding wavelength, thereby generating a photochemical reaction.

[0036] A further advantage lies in forming overhang patterns based on support material that can be removed in a single work step. Support material refers to the material located between the overhang pattern, specifically the cover to be formed, and the substrate.

[0037] A further advantage is the ability to achieve high-precision patterning in the vertical direction, i.e., in the direction of the thickness of the coating layer. While prior art methods and apparatus require adjusting and controlling the focusing of photons to a predetermined focal plane, the present invention allows for direct transmission of light through the coating layer in a spatially resolved, point-like manner, particularly by a beam of light. There is no need to pay particular attention to depth of field or focal plane.

[0038] Furthermore, the present invention advantageously allows for more precise control of the height of the spatial pattern than, for example, grayscale lithography, where exposure is controlled by irradiation dose with respect to depth. This enables the fabrication of taller, more precisely shaped unsupported roof patterns, particularly diaphragms with large hollow chambers located on the underside.

[0039] A further advantage lies in the improved azimuthal resolution, because the preceding method steps are no longer performed. Since there is now only one continuous exposure process, the exposure is no longer negatively affected by the scattering and / or reflection centers of the previously created pattern.

[0040] A further advantage lies in the possibility of very easily adjusting the wavelength and / or dose to the target by individually controllable photon sources and / or by adjusting filters placed in front of broadband photon sources. Therefore, the method according to the present invention can be very easily implemented by the apparatus according to the present invention.

[0041] A further advantage is that although different patterns in each region are described by photons of a predetermined wavelength, they may be selectively patterned differently by multiple exposures.

[0042] A further advantage of the apparatus according to the present invention, equipped with a DMD, is that the heating and developing steps for each individual layer are replaced by a single heating and developing step at the end of exposure. Thus, in a coating layer with n regions (n>1), n-1 heating and developing steps are omitted. This significantly improves process throughput.

[0043] Photosensitive coating layer Embodiments of the present invention are based in particular on the fact that overlapping layouts to be exposed are not exposed simultaneously and especially cumulatively by a multicolor photon source.

[0044] In particular, the n overlapping layouts are such that the i-th layout in the i-th region of the covering layer is i+j of the DMD. * The exposure may be performed so as to be exposed by the mirror in the nth column. In this case, 0 <= j <= m, m = N / n, and N is the number of DMD mirror columns.

[0045] In particular, the temporal switching between layouts makes it possible to expose overlapping layouts. Therefore, per unit of time, the DMD projects at least two layouts, or more precisely, subdivisions of layouts, onto the coating layer.

[0046] In order to enable such exposure, a photosensitive coating layer is provided, in particular, that allows photons having different wavelengths to expose different depth ranges without affecting adjacent depth ranges.

[0047] In a first embodiment of the present invention, the coating layer consists of a single layer. This layer has physical and / or chemical properties that vary particularly with depth, in particular, different sensitivities to photons of a given wavelength. In the first embodiment, the transitions between the various physical and / or chemical properties may be mathematically described by a step function as a function of depth.

[0048] Alternatively, the chemical and / or physical properties change continuously as a function of depth. In this case, the chemical and / or physical properties can be described by a continuously differentiable function. For simplicity, all such changes in the chemical and / or physical properties are called gradients as a function of depth.

[0049] In particular, the chemical and physical properties of the coating layer are uniform, and locally varying photosensitivity may be due to absorption related to wavelength and thickness. The intensity of a photon stream consisting of photons of a given wavelength decreases continuously as a function of penetration depth. Therefore, the photosensitivity also changes as the intensity decreases. In other words, depth selectivity is achieved by a saturation mechanism, i.e., fading. On the one hand, radiation causes exposure, and on the other hand, this makes the exposed area transparent. Thus, a front surface is created that is "eroded" by radiation, thereby forming a 2.5-dimensional topography.

[0050] In a second embodiment of the present invention, the coating layer consists of multiple layers, that is, at least two layers. This embodiment is particularly advantageous because it is particularly easy to fabricate multiple layers by coating methods, especially spin coating methods. Of these layers, each individual layer has physical and / or chemical properties that are well defined with respect to photons of a specific wavelength. In particular, different materials from different manufacturers can be used, each possessing precisely the chemical and / or physical properties necessary to enable the method of the present invention to be carried out, even at the material selection stage.

[0051] In a third embodiment of the present invention, the coating layer may be a combination of both of the first embodiments. That is, the coating layer may consist of multiple layers, and at least one of these layers may have the gradient according to the first embodiment.

[0052] In a particular embodiment of the present invention, the solvents and / or photoinitiators of each different layer do not react across the layer boundaries. Such unfavorable reactions can be minimized by performing the exposure according to the present invention as quickly as possible after the deposition of the coating layer.

[0053] In a particular embodiment of the present invention, a stop layer is inserted between photosensitive layers. This stop layer interrupts the propagation of so-called "chemically enhanced" photoreactions between the layers. This may be used to achieve dose-dependent, stepwise exposure at individual wavelengths.

[0054] In a special embodiment of the present invention, the lateral sensitivity of the photosensitivity within each layer is formed to be of different strengths. Lateral sensitivity refers to the photosensitivity of the coating layer in the direction normal to the direction of illumination. The higher the lateral sensitivity, the less clearly a point in the coating layer can be exposed and / or developed. For example, a ray of light from photons incident parallel to the first layer can expose the first layer more strongly in the lateral direction, i.e., horizontal direction, than the second layer.

[0055] The photosensitive coating layer can be made from any type of photosensitive material, but preferably a resist, particularly a photoresist, is used.

[0056] In a particularly preferred embodiment, the following materials are used, namely, TOK PMER P-LA900PM TOK CR4000 AZ nLOF2000 Series Allresist Atlas 46 Allresist Atlas 46R JSR IX335H JSR WPR5100 JSR THB At least one of these will be used.

[0057] Device The apparatus according to the present invention is preferably a maskless exposure apparatus equipped with at least one micromirror unit (DMD) that is extended to include only a multicolor photon source.

[0058] In a particularly specific embodiment of the present invention, the apparatus according to the present invention may have multiple DMDs capable of simultaneously exposing multiple locations of the coating layer. In particular, individual DMDs may be used for each wavelength, or a DMD may be divided into multiple regions to which different wavelengths are irradiated. In this case, the disclosure can be applied individually and similarly to each DMD.

[0059] An alternative apparatus according to the present invention is a mask-based exposure apparatus extended with a corresponding multi-color photon source. This makes it possible to apply the method according to the present invention to a mask-based exposure apparatus as well.

[0060] All apparatuses according to the present invention particularly include a multi-color photon source. This photon source is generally part of an optical system consisting of a very large number of optical elements. This optical system will be described in detail below.

[0061] photon source In the following text, a photon source means a component or group of components capable of emitting photons having at least one unique wavelength. In special embodiments, individual photon sources may be multicolored.

[0062] In the first embodiment of the present invention, the photon source is a device that emits photons having a multicolor spectrum, particularly a mercury lamp. Mercury has a multicolor spectrum in the UV range. For example, the photon source may be provided with a filter that allows only photons of the required wavelength to pass through. By switching this filter, switching between different wavelengths can be performed.

[0063] In the second embodiment of the present invention, the photon source is a collection of individual monochromatic photon sources.

[0064] In a special embodiment of the second embodiment according to the present invention, each of the individual monochromatic photon sources is a light-emitting diode (LED) or an LED-array. Since each LED or LED array can always emit only one monochromatic radiation, a plurality of corresponding components having different wavelengths must be used. The possibility of switching each different LED or LED array electronically, in particular, can advantageously eliminate the need for the use of mechanical filters.

[0065] However, to be on the safe side, in addition to the possibility of individually electronically switching each monochromatic photon source, a light source whose wavelength can be changed by another mechanism is also called a "filter." Therefore, when referring to filtering of such a single monochromatic photon source in this specification, it means that this one, and only, monochromatic photon source emits photons, while all other monochromatic photon sources do not emit photons.

[0066] In the example structure, the described monochromatic photon sources are realized as polychromatic photon sources, each with a different spectral distribution, and are simply referred to as monochromatic or as having different wavelengths.

[0067] optical system The optical system of the apparatus according to the present invention is a collection of optical elements and / or mechanical elements and / or electrical elements. The optical system has at least one photon source.

[0068] Another element, namely, DMD • Mirror • Lens Prism · Aperture Mask It's okay to have that.

[0069] Preferably, at least one optical element is also present in the secondary path between the DMD and the coating layer, i.e., in the optical path.

[0070] More preferably, the optical element is an optical element for imaging.

[0071] In a particularly preferred embodiment of the present invention, the optical element is such that the active structure of the DMD can be imaged into an image within the coating layer by mathematical transformations, particularly affine transformations. Shear and scaling transformations are especially preferred. Such an optical system has already been described in International Publication No. 2018113918.

[0072] Relative movement The apparatus according to the present invention is preferably designed such that the substrate holder on which the substrate coated with a photosensitive coating layer is mounted can be actively moved, while the optical system remains stationary. Alternatively, the apparatus can be designed such that the optical system is moved while the substrate holder remains stationary, or so that the optical system and / or the substrate holder can be moved, or so that a deflection device for lateral movement is provided. Lateral movement may be omitted when the exposure area is small or the exposure element is large.

[0073] Therefore, it is preferable that relative movement between the substrate holder and the optical system be possible.

[0074] By fixing the substrate in the substrate holder, precise relative movement between the substrate and the optical system becomes possible.

[0075] method The method according to the present invention makes it possible to form cavities by patterning sidewalls and covers in MEMS and microfluidics regions in a single exposure step.

[0076] The method according to the present invention enables the simultaneous exposure of redistribution layers and interlayer connections, such as those used in advanced packaging.

[0077] The method according to the present invention is advantageous in that, - Maskless exposure equipment, especially maskless laser exposure equipment, - In particular, another maskless system including a laser scanner, - Mask-based exposure systems, particularly mask aligners, especially steppers and scanners with interchangeable or displaceable masks. It may be used for this purpose.

[0078] In a particular embodiment, the method according to the present invention may be used in a mask-based exposure apparatus.

[0079] The method according to the present invention is preferably used in a maskless exposure apparatus, particularly a maskless laser exposure apparatus. A preferred method according to the first embodiment of the present invention is described in detail below.

[0080] In the first method step of the first method according to the present invention, the substrate is coated with at least one first photosensitive layer. For this purpose, the substrate is preferably loaded into a coating apparatus specifically provided for coating and coated therein.

[0081] The coating is preferably carried out by spin coating. If the photosensitive coating layer is the coating layer of the first embodiment, that is, a coating layer having only one layer, the next second method step of coating the subsequent layer can be skipped.

[0082] This assumes that a single coating layer has at least two regions, which allows for sufficiently accurate resolution of the various layouts to be exposed.

[0083] In the second method step of the first method according to the present invention, the substrate is coated with at least one second photosensitive layer. Preferably, the coating of this second photosensitive layer is carried out in the same coating apparatus. Thus, the coating apparatus preferably comprises at least two complete coating means, in particular hoses or nozzles, to prevent mixing of different photosensitive resists. According to the present invention, the method is not limited to this second photosensitive layer. According to the present invention, if the apparatus according to the present invention has a photon source capable of emitting photons having n wavelengths that are optically separable from each other, it may be significant to form n independently exposureable photosensitive layers in superposition. Hereinafter, the method according to the present invention will be described mainly based on two layers. The extension to n layers is similarly applicable.

[0084] In a special embodiment of the present invention, the second method step is unnecessary as long as the wavelength sensitivity of the deposited first layer changes in the thickness direction as a function of position.

[0085] In the third method step of the first method according to the present invention, the coated substrate is loaded into the apparatus according to the present invention, and a relative movement is performed between the substrate and the optical system to a first position.

[0086] In the fourth method step of the first method according to the present invention, at the first position, the mirror of the DMD is switched to the first configuration. Particularly for process acceleration, the switching of the DMD mirror to the first configuration may have already occurred during the relative movement by the third method step.

[0087] In the fifth step of the first method according to the present invention, at a first position, a photon source irradiates a mirror of a DMD in a first configuration with photons of a first wavelength. Then, the first layout to be formed by the DMD is projected onto a first photosensitive region. Focusing is advantageously unnecessary.

[0088] Photons having a first wavelength advantageously penetrate all present regions. However, according to the present invention, since only some regions of the coating layer, particularly just one region, are photosensitive to photons of the first wavelength, some regions of the coating layer, particularly just one region, can also be photochemically altered.

[0089] In the sixth method step of the first method according to the present invention, at the first position, the mirror of the DMD is switched to the second configuration.

[0090] In the seventh step of the first method according to the present invention, at a first position, a mirror of the DMD in the second configuration is irradiated with photons of a second wavelength by a photon source. Then, the second layout to be formed by the DMD is projected onto the second region.

[0091] Advantageously, no adjustment of the focus to the second region is necessary. Photons with the second wavelength penetrate all existing regions. However, because some regions, in particular just one region, are sensitive to photons of the second wavelength, some regions, in particular just one region, can also be photochemically altered.

[0092] If there are more than two photosensitive regions, the sixth and seventh method steps must be repeated accordingly with different configurations of the DMD mirror and different wavelengths.

[0093] In the eighth method step of the first method according to the present invention, a relative movement between the substrate and the optical system to a second position is performed.

[0094] Next, steps 4 through 8 of the method are repeated until all surfaces to be processed are exposed.

[0095] In the ninth step of the first method according to the present invention, the substrate is unloaded and the coating layer on the substrate is developed. The development may be performed advantageously only once.

[0096] The method steps described do not necessarily have to be performed in this order. Preferably, some of the method steps described are performed simultaneously. In particular, the relative movement, exposure, and DMD switching are performed simultaneously or at least so quickly that it is no longer necessary or possible to consider the method steps separately from each other.

[0097] In particular, this simultaneity significantly increases throughput and improves economic efficiency. The transitions between several method steps are at least smooth.

[0098] In addition to the possibility of using the method according to the present invention in a maskless exposure apparatus equipped with a DMD, the method according to the second embodiment can also be used in a mask exposure apparatus.

[0099] The first three method steps of the second method according to the present invention are the same as the first three method steps of the first method according to the present invention.

[0100] In the fourth method step of the second method according to the present invention, the substrate is aligned relative to the first mask in a mask exposure apparatus. Preferably, the substrate is brought to a terminal position and fixed in place. The first mask is then moved relative to the substrate. In this case, the alignment is preferably performed based on alignment marks between the first mask and the substrate.

[0101] In the fifth step of the second method according to the present invention, the coating layer is exposed over its entire surface with photons of a first wavelength through a first mask.

[0102] In the sixth step of the second method according to the present invention, the first mask is replaced with the second mask.

[0103] In the seventh step of the second method according to the present invention, the substrate is aligned relative to the second mask in a mask exposure apparatus. Preferably, the substrate remains in its fixed end position. Then, preferably, the second mask is moved relative to the substrate. In this case, the alignment is preferably performed based on alignment marks between the second mask and the substrate.

[0104] In the eighth method step of the second method according to the present invention, the coating layer is exposed over its entire surface with photons of a second wavelength through a second mask.

[0105] As long as the coating layer is designed for further exposure, then the sixth to eighth method steps may be repeated for a different mask and wavelength.

[0106] In the ninth step of the second method according to the present invention, the substrate is unloaded.

[0107] In the tenth step of the second method according to the present invention, the coating layer on the substrate is developed. The development may be performed advantageously only once.

[0108] Further advantages, features, and details of the present invention will become apparent from the following description of preferred embodiments and the drawings. [Brief explanation of the drawing]

[0109] [Figure 1a] This figure shows the first method step of the first method according to the present invention. [Figure 1b] This figure shows the second method step of the first method according to the present invention. [Figure 1c] This figure shows the third method step of the first method according to the present invention. [Figure 1d] This figure shows the fourth and fifth method steps of the first method according to the present invention. [Figure 1e]This figure shows the sixth and seventh method steps of the first method according to the present invention. [Figure 1f] This figure shows the eighth method step of the first method according to the present invention. [Figure 2a] This figure shows the third and fourth method steps of the second method according to the present invention. [Figure 2b] This figure shows the fifth method step of the second method according to the present invention. [Figure 2c] This figure shows the sixth, seventh, and eighth method steps of the second method according to the present invention.

[0110] In the diagram, identical components or components having the same function are denoted by the same reference numeral.

[0111] The drawings are not to an accurate scale. In particular, the photosensitive layers 3a and 3b and all elements of the optical system 4 are not shown to an accurate scale compared to substrate 1.

[0112] The principle of the present invention is most simply and efficiently illustrated, for example, by illustrating each region as an individual coated layer. Accordingly, the method of the present invention will be explained in Figures 1a to 1f below, based on the coating layer 3. This coating layer 3 consists of two photosensitive layers 3a and 3b. Both of these photosensitive layers 3a and 3b form regions that respond to photons of different wavelengths with different intensities. As those skilled in the art will recognize, both layers 3a and 3b can more generally be considered as regions that are part of a single layer which will eventually become equal to the coating layer. In this case, the coating of the two layers in Figures 1a to 1b must be replaced with the coating of a single layer.

[0113] Figure 1a shows a first method step of a first method according to the present invention. In this first method step, the substrate 1 is coated with a first photosensitive layer 3a via a first single coating element 2a of a coating system 2, preferably via a hose or nozzle. That is, in the first method step, the photosensitive layer 3a corresponds to a first region of the coating layer. Coating is preferably carried out by a spin coater. In this case, the photosensitive layer 3a is distributed across the substrate surface of the substrate 1 by rotation of the substrate 1 about a central axis, as shown in Figure 1. Any other form of coating process may be used to deposit the photosensitive layer 3a onto the substrate 1. The photosensitive layer 3a is sensitive to a first type of photon having a first wavelength.

[0114] Figure 1b shows a second method step of the first method according to the present invention. In this second method step, the substrate 1 is coated with a second photosensitive layer 3b via a second single coating element 2a of the coating system 2, preferably via a hose or nozzle. That is, in the second method step, the photosensitive layer 3b corresponds to a second region of the coating layer. Coating is preferably carried out by a spin coater. In this case, the photosensitive layer 3b is distributed across the surface of the first photosensitive layer 3a by the rotation of the substrate 1 about a central axis, as shown in Figure 1b. Any other form of coating process may be used to deposit the photosensitive layer 3a onto the surface of the photosensitive layer 3a. The photosensitive layer 3b is sensitive to a second type of photon having a second wavelength. Both photosensitive layers 3a,3b form the coating layer 3. It is possible to add further photosensitive layers to the coating layer 3. However, in order to keep the drawings as simple as possible, the method according to the present invention will be described only based on a layer row 3 having two photosensitive layers 3a, 3b.

[0115] Since the photosensitive layers 3a and 3b each have different physical and / or chemical properties, particularly with respect to their sensitivity to the wavelength of incident photons, it is especially advantageous to deposit the materials forming the photosensitive layers 3a and 3b via two separate individual coating elements 2a and 2b. Alternatively, the coating system 2 may have only one coating element.

[0116] Figure 1c shows a third method step of the first method according to the present invention. In this third method step, the substrate 1 is positioned in a first position below the optical system 4. The relative movement between the substrate 1 and the optical system 4 is shown in subsequent drawings as the substrate 1 being moved relative to the optical system 4, which is considered to be stationary. The optical system 4 has a photon source 5, in particular, consisting of at least two individual photon sources 5a, 5b. The individual photon sources 5a, 5b are graphic representations of the origin of photons having different wavelengths. These individual photon sources 5a, 5b do not necessarily have to be two different components or groups of components. For example, the photon source 5 could be a mercury radiation source. Since mercury can emit photons having different wavelengths, the mercury radiation source may consist of a plurality, in particular at least two individual photon sources 5a, 5b. The photon source 5 or optical system 6 according to the present invention has filters 6a, 6b. These filters 6a and 6b allow us to determine which photons from each of the individual photon sources 5a and 5b are used for exposure. The filters do not necessarily have to be interpreted as a single component or group of components. When using individual photon sources 5a and 5b composed of LEDs or LED arrays, mechanical, electrical, or optical filters are unnecessary because the photon flow of the corresponding individual photon sources 5a and 5b can be directly controlled by switching the LEDs on or off. In this context, filtering the photons of individual photon sources 5a and 5b means switching off the photon sources 5a and 5b. The filters 6a and 6b are preferably formed as distinct components or groups of components and are electronically and / or optically and / or mechanically switched if the underlying photon source 5 has at least one individual photon source 5a or 5b that cannot be switched at all, cannot be switched quickly enough, or is spontaneously multicolored. Therefore, in order to accurately separate the two emission lines of the multicolor mercury spectrum from one another, the photon source 5, which consists of a mercury radiation source, must have filters 6a and 6b.

[0117] The exposure principle will be explained in detail in the following two figures based on layouts 10a and 10b. Positive-type resists and / or negative-type resists may be used for the individual photosensitive layers 5a and 5b. In this example, we will explain based on a negative-type resist, that is, the resist remaining after the corresponding heating and / or developing steps, where the material of the photosensitive layers 3a and 3b that collide with the photons is crosslinked at that point. The relevant area is shown as a black region.

[0118] Figure 1d shows the fourth and fifth method steps of the first method according to the present invention. In these fourth and fifth method steps, the mirrors of the DMD7 are switched to the first configuration. Furthermore, filter 6a is opened and filter 6b is closed. Only photons of the first wavelength from the first single photon source 5a can be projected onto the DMD7. The DMD7 then performs spatially resolved filtering of the photon stream by its individual mirrors, projecting the desired layout section 10a as secondary rays 8a onto the coating layer 3. Thus, depending on the wavelength of the first type of photon, chemical or physical reactions between photons and molecules occur exclusively in the first photosensitive layer 3a, that is, only within the depth range 9a. Unlike the prior art, the method according to the present invention does not require focusing the photon stream onto the first depth range 9a of the first photosensitive layer 3a. Photons of the first wavelength pass through the second photosensitive layer 3b. In this case, no chemical and / or physical reactions that would result in exposure to the second depth range 9b occur in this second photosensitive layer 3b.

[0119] The enlarged view shows the layout section 10a projected onto the photosensitive layer 3a by the DMD7. The individual mirrors of the DMD7 are switched so that only the outer-peripheral mirrors, i.e., the lateral mirrors, expose the photosensitive layer 3a with photons. This exposes the edge-like regions that will later form the walls of the cavity 11.

[0120] Figure 1e shows the sixth and seventh method steps of the first method according to the present invention. In these sixth and seventh method steps, the mirrors of the DMD7 are switched to a second configuration. Furthermore, filter 6b is opened and filter 6a is closed. Only photons of the second wavelength from the second single photon source 5b can be projected onto the DMD7. Subsequently, the DMD7 performs spatially resolved filtering of the photon stream by its individual mirrors, projecting a desired layout division 10b, which is generally different from the layout division shown in Figure 4, onto the coating layer 3 as secondary rays 8b. Thus, depending on the wavelength of the first type of photon, chemical or physical reactions between photons and molecules occur exclusively in the second photosensitive layer 3b, i.e., only within the depth range 9b. Unlike the prior art, the method according to the present invention does not require focusing the photon stream to the second depth range 9b of the second photosensitive layer 3b. Photons of the second wavelength generally also reach the first photosensitive layer 3a. In this case, no chemical and / or physical reactions that would cause exposure in the second depth range 9a occur in the first photosensitive layer 3a.

[0121] The enlarged view shows the layout section 10b projected onto the photosensitive layer 3b by the DMD7. Almost all of the individual mirrors of the DMD7 are switched to project photons having a second wavelength onto the photosensitive layer 3b. Only a few mirrors that can be exposed in the upper left or lower right region are switched not to project photons onto the photosensitive layer 3b. This creates the region according to the present invention that forms an entrance / exit 13 in the cover 12 after the subsequent heating and / or developing steps, and connects the outside world to the cavity 11 (see Figure 1d).

[0122] Figure 1f shows the eighth method step of the first method according to the present invention. In this eighth method step, a relative movement occurs between the substrate 1 and the optical system 4 to the second position. Note that the method steps shown in Figures 1d to 1f may be repeated for any number of positions.

[0123] After these method steps, subsequent process steps, particularly the development of coating layer 3, are performed. Advantageously, only one development step is required.

[0124] The drawings should give the impression that the method according to the present invention is a step-and-repeat process in which at least one three-dimensional pattern consisting of a cavity 11, a cover 13, and an entrance / exit 12 is formed at one or more locations in a layer row 3 on a substrate 1. The method according to the present invention is very well suited to positioning the optical system 4 relative to the substrate 1 at a first position to form such a three-dimensional pattern at this first position, and then performing multiple further relative movements to a plurality of other positions to form further three-dimensional patterns, but it can bring about more than this.

[0125] In particular, if the three-dimensional pattern to be formed is larger than the exposure pattern of the DMD7 itself, the three-dimensional pattern must be exposed during the relative movement between the optical system 4 and the substrate 1 by continuous programming of the DMD's mirrors. The use of the photon source 5 and the layer row 3 must be considered in particular in terms of such continuous relative movement and the continuous switching process of the DMD7's mirrors.

[0126] An alternative method according to the present invention based on mask technology is described below.

[0127] Figures 1a and 1b can also be used in the second method according to the present invention, and will not be shown again.

[0128] Figure 2a shows the third and fourth method steps of the second method according to the present invention. In these third and fourth method steps, a substrate 1 with a coating layer 3 is loaded into a mask exposure apparatus. This mask exposure apparatus also has an optical system 4' designed for surface exposure. In particular, it may be provided with optical elements that reflect photons toward the substrate 1, such as mirrors, preferably cold mirrors 14. The apparatus has a photon source 5 comprising at least two individual photon sources 5a, 5b and filters 6a, 6b. References to the individual photon sources 5a, 5b and filters 6a, 6b based on the preceding textual portion apply similarly.

[0129] Figure 2b shows a fifth method step of the second method according to the present invention. In this fifth method step, a first mask 15a having a first aperture 16a is inserted between the optical system 4' and the substrate 1. The first mask 15a is preferably aligned by alignment marks (not shown), particularly relative to the substrate 1. A filter 6a (not shown) is opened or removed, or a second filter 6b is kept closed. This causes a photon having a first wavelength to be emitted from the first single photon source 5a and projected onto the coating layer 3 through the aperture 16a of the first mask 15a. Since only the first photosensitive layer 3a of the layer row 3 is sensitive to the first wavelength photon from the first single photon source 5a, chemical and / or physical reactions occur only in the exposed first depth range 9a, even though the photon also penetrates the second photosensitive layer 3b.

[0130] Figure 2c shows the sixth, seventh, and eighth method steps of the second method according to the present invention. In these sixth, seventh, and eighth method steps, first, a first mask 15a (not shown) is replaced with a second mask 15b. This second mask 15b has a second aperture 16b. The second mask 15b is preferably aligned by alignment marks (not shown), particularly relative to the substrate 1. According to the present invention, a filter 6b (not shown) is opened or removed or the second filter 6a is kept closed. This causes photons having a second wavelength to be emitted from the second single photon source 5b and projected onto the coating layer 3 through the aperture 16b of the second mask 15b. Since only the second photosensitive layer 3b of layer row 3 is sensitive to the second wavelength photon of the second single photon source 5b, chemical and / or physical reactions occur only in the exposed second depth range 9b, even though this photon also reaches the first photosensitive layer 3a.

[0131] After these method steps, subsequent process steps, particularly the development of coating layer 3, are performed. Advantageously, only one development step is required. [Explanation of symbols]

[0132] 1 circuit board 2. Covering System 2a,2b Individual covering elements 3 Covering layer 3a,3b area / photosensitive layer 4,4' optics 5. Radiation devices, photon sources 5a, 5b Individual photon sources 6a, 6b filters 7. Digital Micromirror Unit, Digital Micromirror Device (DMD) 8a,8b Secondary ray 9a,9b Exposed depth range 10a, 10b Layout divisions 11 Cavity 12 Covers 13 Entrances and Exits 14 Mirror 15a, 15b Mask 16a,16b opening

Claims

1. A method for exposing a photosensitive coating layer (3) having at least one photosensitive first region (3a) and a photosensitive second region (3b), wherein the first region (3a) reacts to photons of a first wavelength, the second region (3b) reacts to photons of a second wavelength, the first wavelength is different from the second wavelength, and the method is - The coating layer (3) is exposed to the photon of the first wavelength, - Expose the coating layer (3) with the photon of the second wavelength. A method having steps, particularly a sequence.

2. The method according to claim 1, wherein the coating layer (3) is exposed by a dynamically controllable device, particularly a digital micromirror unit (7).

3. The method according to at least one of claims 1 to 2, wherein the coating layer (3) is exposed through at least one mask (15a, 15b).

4. The method according to at least one of claims 1 to 3, wherein exposure of the coating layer (3) with photons of the first wavelength causes a photochemical reaction to occur only in the first region (3a), and exposure of the coating layer (3) with photons of the second wavelength causes a photochemical reaction to occur only in the second region (3b).

5. The method according to at least one of claims 1 to 4, wherein the coating layer (3) is exposed in a spatially resolved manner and / or in a point manner, particularly using a beam of light.

6. The method according to at least one of claims 1 to 5, wherein the coating layer (3) is exposed by an individually controllable photon source (5), and the wavelength and / or dose of the photons are adjusted.

7. The method according to at least one of claims 1 to 6, wherein the coating layer (3) is exposed by adjusting filters (6a, 6b) provided in front of a broadband photon source (5) to adjust the wavelength and / or dose.

8. The method according to at least one of claims 1 to 7, wherein different depth ranges of the coating layer (3) are reacted in succession.

9. The method according to at least one of claims 1 to 8, wherein the coating layer (3) has sensitivity to photons of the same wavelength that varies over the thickness of the coating layer (3).

10. The method according to at least one of claims 1 to 9, wherein the first region (3a) is formed as a first layer, and the second region (3b) is formed as a second layer on the first layer.

11. An apparatus for exposing a photosensitive coating layer (3) having at least one photosensitive first region (3a) and a photosensitive second region (3b), wherein the photosensitive first region (3a) reacts to photons of a first wavelength, the photosensitive second region (3b) reacts to photons of a second wavelength, the first wavelength is different from the second wavelength, and the apparatus includes a radiation device (5) for exposing the coating layer (3) with photons of the first wavelength and for exposing the coating layer (3) with photons of the second wavelength.

12. The apparatus according to claim 11, comprising a dynamically controllable apparatus for exposing the coating layer (3), particularly a digital micromirror unit (7).

13. The apparatus according to at least one of claims 11 to 12, comprising at least one mask (15a, 15b) for exposing the coating layer (3).

14. The apparatus according to at least one of claims 11 to 13, further comprising a movable holder for moving the coating layer (3) relative to the radiation device (5).

15. An article manufactured by the method according to at least one of claims 1 to 10 and / or the apparatus according to at least one of claims 11 to 14.

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