CN213240799U - Photoetching machine - Google Patents

Abstract

The utility model relates to a lithography machine. The lithography machine may comprise an arrangement for electrical contact alignment for leveling alignment of an array of probes, pens, tips etc. relative to a substrate, the machine comprising a mechanism for positioning the probe array or the substrate relative to each other to automatically align the probe array and the substrate parallel to each other for subsequent lithographic fabrication, wherein a plurality of independent circuits are formed by configuring regions of the array and regions of the substrate to be partially conductive and connected to opposing electrodes, and vice versa.

Description

Photoetching machine

Technical Field

The present invention relates to lithography machines, and more particularly to electrical contact type automatic alignment pen arrays in lithography machines for nano/micro manufacturing, nano patterning or nano printing, and cantilever-less scanning probe lithography machines.

Background

Recent breakthrough advances in scanning probe lithography by the Mirkin team, led by Chad a. Mirkin, university at northwest, have addressed many of the technical limitations of traditional nanopatterning strategies, using innovative methods to control both nanoscale and microscale (i.e., 1nm-10 μm in length) molecular and material structures.

In contrast to the Cantilever-based paradigm that has traditionally been used, morkin invented Cantilever-Free Scanning Probe Lithography (CF-SPL), which relies on a new structure in which the Cantilever is replaced with an inexpensive elastomeric film containing up to millions of pyramidal tips on a rigid substrate and providing large scale scaling while maintaining high resolution.

As recognized by morkin, a large number of parallel tip arrays can be used for direct molecular printing (a technique known as Polymer Pen Lithography (PPL)) or, when combined with near-field and far-field Lithography, for diffraction-free patterning with light (a method known as Beam Pen Lithography (BPL)).

In order to produce uniform feature sizes over large areas with PPL or BPL, the probe array must be aligned parallel to the substrate. Typically, this process is performed manually by optically inspecting each corner of the probe array and identifying the point of contact, or automatically by measuring the forces resulting from physical contact between the probe array and the substrate. However, there is a need for automatic alignment without mechanical force measurement.

SUMMERY OF THE UTILITY MODEL

To this end, the present invention provides a lithographic machine configured to automatically align its probe array and/or substrate parallel to each other for lithographic manufacturing.

The disclosed embodiments provide apparatus and methods for photolithography, nanoimprinting, and nanopatterning.

The disclosed embodiments provide an electrical contact alignment strategy for leveling alignment (level) of a probe array relative to a substrate.

In accordance with at least one disclosed embodiment, a plurality of independent circuits are formed by configuring the probe array region and the substrate region to be partially conductive and connected to opposing electrodes (or connecting opposing electrodes to different electrically isolated regions of the array).

In accordance with at least one disclosed embodiment, application of a voltage bias is used to induce a measurable current that evidences contact between an area of the substrate and a corresponding area of the array.

According to at least one disclosed embodiment, the iterative control of the array and movement relative to the substrate (and vice versa) while measuring the current (indicative of electrical contact) between the array and corresponding conductive regions of the substrate enables the array and substrate to be levelly aligned relative to each other.

According to an aspect of the application, a lithographic apparatus can include: a probe array, wherein the probe array or a substrate on which a plurality of components are to be fabricated by photolithography are positioned relative to each other; and means for automatically aligning the probe array and the substrate parallel to each other for subsequent lithographic fabrication.

The lithography machine may further include: a motorized tilt/tilt table that enables positioning of a probe array or a substrate, the positioning enabling tilting of the probe array or the substrate in two orthogonal planes. According to an embodiment of the present application, self-alignment may apply a voltage bias to the probe array or the substrate to induce a measurable current indicative of electrical contact between an area of the substrate and a corresponding area of the probe array. The self-alignment may form a circuit capable of carrying current.

According to an embodiment of the application, the self-alignment may be performed by movement of the probe array or the substrate relative to each other while measuring the current between the probe array and the corresponding conductive region of the substrate. According to an embodiment of the present application, the self-alignment may position the probe array or the substrate such that the probe array and the substrate are positioned within 0.005 ° of parallel to each other in less than ten minutes.

According to an embodiment of the present application, the probe array may be one of a cantilever-less scanning probe array, a polymer pen/probe array, or a beam pen/probe array. According to an embodiment of the application, the lithography machine is a polymer pen lithography machine, and wherein the probe array comprises a large number of probes arranged in parallel, each probe serving as a point source for direct molecular printing.

According to an embodiment of the application, the lithography machine may be formed as a beam pen lithography machine. The probe array may include a large number of probes arranged in parallel for performing diffraction-free patterning using light. The probe array may include tips that may be coated with an opaque material having holes at the apex of the tips.

According to an embodiment of the application, the lithography may be cantilever-less scanning probe lithography. The lithography machine may be configured to produce nanoscale features in the range of 1nm to 10 μm on the substrate in at least one dimension.

According to an embodiment of the present application, a conductive material layer may be deposited at least two corners and four regions of a center-side (center-side) area of a probe array or a substrate. The layer of conductive material may be 5nm-5 μm. The conductive material may include one of Au, Al, Ag, Pt, Ti, or Cr.

According to an embodiment of the present application, applying voltages to the four corner regions and grounding the four side center regions (or vice versa) may configure four independent circuits. The measurement of the current of each of the four circuits may be indicative of the relative positioning of the probe array and the substrate.

According to an embodiment of the present application, a lithographic machine may include an arrangement for electrical contact self-alignment for lithography, the arrangement comprising: providing a probe array; positioning a probe array or a substrate relative to each other, wherein a plurality of components are to be fabricated on the substrate by photolithography; and automatically aligning the probe array and the substrate parallel to each other for subsequent lithographic fabrication.

According to an embodiment of the application, the repeated movement of the motorized tilt/tilt table to automatically align the probe array and the substrate in parallel for subsequent lithographic fabrication is performed in response to repeated measurements of current between the probe array and the plurality of regions of the substrate.

With the arrangement for aligning probes and/or substrates of the present invention, an automated basis for lithographic manufacturing is provided.

Additional features of the present invention will become apparent to those skilled in the art upon consideration of the exemplary embodiment exemplifying the best mode of carrying out the invention as presently perceived.

Drawings

In particular, the detailed description makes reference to the accompanying drawings, wherein:

FIG. 1 provides an example of an overall lithography machine according to the disclosed embodiments.

FIG. 2 provides another example of an overall lithography machine according to the disclosed embodiments.

Fig. 3 provides an example of a modification to a probe array in accordance with at least one of the disclosed embodiments.

Fig. 4 and 5 provide examples of custom designed array holders for electrical contact self-alignment according to at least one disclosed embodiment.

Fig. 6 and 7 provide illustrations of exemplary interactions between upper and lower portions of a custom holder for a probe array according to at least one disclosed embodiment.

FIG. 8 illustrates the principles of operation of the electrical contact self-alignment mechanism and method provided in accordance with at least one disclosed embodiment.

FIG. 9 illustrates a series of operations that may be performed to perform automatic alignment of a pen array provided in accordance with at least one disclosed embodiment.

FIG. 10 illustrates a functional diagram showing a lithographic machine including a self-alignment mechanism provided in accordance with the disclosed embodiments.

Detailed Description

For purposes of the present invention, reference is made to various types of arrays (generally referred to herein as "probe arrays," i.e., arrays of probes of other types used for nanopatterning, nanoimprinting, lithography, and the fabrication of parts, devices, materials, etc.). Accordingly, one of ordinary skill in the art will appreciate that the term "probe array" refers to any type of array of pens, probes, tips, etc. for dispensing, removing, or imprinting material or substrates, as well as for transmitting electrical current, magnetic fields, light, heat, or other forms of energy.

With this understanding in mind, the disclosed embodiments provide apparatus and methods for printing, lithography, nanofabrication, nanoimprinting, and nanopatterning.

In this technique, conventional mechanisms for aligning the pen array parallel to the substrate require manual alignment, for example, by optically inspecting each corner of the probe array and identifying the contact points. This conventional approach has various drawbacks: (i) this process is cumbersome, typically requiring more time than the actual patterning itself; (ii) the contact points are determined ambiguously by scientists, resulting in misalignment and poor, imperfect or defective patterned material; (iii) out-of-plane optical resolution is limited to about 500nm, further resulting in alignment inaccuracies; and (iv) the tips must be optically transparent, which is especially problematic for gold coated BPL array tips.

Another conventional alignment strategy that has recently been developed is based on a force feedback paradigm. Considering the elastomeric nature of the polymer pen array, this approach relies on maximizing the compressive force of the array at a predetermined compression distance. While this strategy enables some degree of automation of the array leveling alignment routine, it lacks reliability and versatility.

The compression can be derived from either the polymer pen or the elastomeric layer between the polymer pen and the rigid glass carrier. However, robust control of the uniformity and thickness of the rigid glass carrier is difficult to achieve during the manufacturing process. In addition, the deposition of thin layers of hard materials (e.g., gold, aluminum, silicon oxide, silicon nitride) on polymer pens required for BPL applications and higher resolution PPL nanopatterning is incompatible with force feedback alignment strategies.

Accordingly, the presently disclosed embodiments are a result of developing an improved alignment method that enables automation and more reliable alignment procedures. Thus, such embodiments have particular utility for enabling both PPL manufacturing and BPL manufacturing, as well as for enabling commercialization of both PPL instrumentation and BPL instrumentation.

Embodiments of the disclosed electrical contact alignment strategy are based on the innovative technical realization that a tip array and a substrate can form an electrical circuit. This may be accomplished, for example, by configuring the tip and substrate to be partially conductive and connected to opposing electrodes (or to connect opposing electrodes to different electrically isolated regions of the probe array), and resistance is added to the circuit. With such a configuration, applying a voltage bias will result in a measurable current that evidences that the tip is contacting (i.e., in contact with) the substrate, while no measurable current is present when the tip is not in contact with the substrate.

Fig. 3 provides an example of a modification to the probe array 100 in accordance with at least one of the disclosed embodiments. Referring to fig. 1-10, a probe array 100 (e.g., a polymer pen array) may be mounted to a holder 115 while a voltage bias and ground are applied to the probe array 100. Accordingly, the probe array 100 may be positioned within the array holder 115, after which the auto-alignment process is initiated. As shown in fig. 1, this is performed by, for example, applying a voltage to the four corner regions 105 and grounding the four side center regions 110 (or vice versa). Since eight regions are created, applying these voltage levels enables four independent circuits to be configured.

More specifically, as shown in fig. 3, to implement an electrical-based alignment paradigm, various configurations of array materials can be provided to implement nanopatterning and other types of lithographic operations. For example, one such configuration may be achieved by providing a thin layer (e.g., 5nm-5 μm) of deposited conductive material (e.g., gold (Au), aluminum (Al), silver (Ag), platinum (Pt), titanium (Ti), or chromium (Cr)) for forming electrical contacts 105 at the corners of probe array 100 and a corresponding number of electrical contacts 110 in the side central regions of the probe array, as shown in fig. 3.

In the example shown in FIG. 3, the number of corner contacts 105 deposited is four; likewise, the number of side electrical contacts 110 is four. However, a greater or lesser number of contacts may be used without departing from the utility and scope of the disclosed embodiments.

In addition, the shape of the probe array need not be square or orthogonal; rather, any shape is possible. Additionally, the electrical contacts 105, 110 are not required to be specially shaped. Furthermore, the deposition of material on the probe array need not be precisely on the corners of the probe array. Rather, it is only necessary to electrically isolate the deposited material from the functional portions of the array 100 and other electrical contact areas 105, 110.

Fig. 4-7 provide examples of custom designed array holders for electrical contact self-alignment according to at least one disclosed embodiment. Fig. 4-7 show examples of configurations of the array holder 115, wherein the holder 115 comprises two parts: a lower member 125 (shown in fig. 4-5) and an upper member 130 (shown in fig. 6-7).

As shown in fig. 4-5, the lower member 125 provides support for the probe array 100. The lower part 125 comprises a plurality of electrodes 120 corresponding to the electrical contact areas 105, 110 provided on the array 100.

After loading the array into the lower part 125 of the holder, the conductive areas on the array 100 face the corresponding electrodes 120 on the lower part 125. The electrodes 120 can be introduced on the lower part 125 of the holder by incorporating pads of conductive material, for example copper pads with spring-loaded pins, to compensate for potential defects in the planarity of the probe array. As noted above, there is no particular requirement for a particular number or positioning of the conductive areas 105, 110 on the array 100; however, the positioning and number of these areas 105, 110 should correspond to the positioning and number of electrodes 120 on the lower part 125 of the holder.

Fig. 6-7 show the upper member 130 of the array holder 115. As shown in fig. 6, the upper component 130 includes the same number of electrodes 135 aligned with corresponding electrodes 120 on the lower component 125. In this example of the disclosed embodiment, the lower component 125 is coupled or attached to the upper component 130. The upper component is in turn coupled, attached or mounted to a tilting table (further explained herein with reference to fig. 10). According to at least one disclosed embodiment, the electrodes 135 in the upper component 130 may be wired to voltage bias and ground. Such a configuration enables electrical signals to propagate fully to the corresponding corners of the array 100 and also enables rapid and efficient exchange of the probe array 100.

FIG. 8 illustrates the principles of operation of the electrical contact self-alignment mechanism and method provided in accordance with at least one disclosed embodiment. Fig. 8 illustrates an auto-alignment process for a single axis (e.g., a). As part of this alignment process, the array can be disposed and positioned on the disclosed array holder for contact with the substrate using a motorized translation stage (as discussed further herein with reference to fig. 10). The contact corresponds to "shorting" or electrically contacting anywhere from one to four circuits/corners. In this example, one shorted circuit indicates misalignment, while two or more shorted circuits indicate perfect alignment. After determining the imperfect alignment, the array may be moved out of contact with the substrate and may be tilted along the alignment axis to improve alignment.

For example, for axis a, tilting toward the right may be performed without contacting the corner. In this particular example, a resolution of 4 × 10 may be used^-5Degree (0.7 micro radian) and minimum step length of +/-4 multiplied by 10^-5A high precision actuator with a maximum step of + -3.5 deg. performs the tilting.

To perform the single axis alignment of this example, the operations of determining the number of shorts and adjusting the inclination of the array may be iteratively performed until one of the plurality of corners on the opposite side or array is shorted, thereby indicating electrical contact. In a multi-dimensional (e.g., two-dimensional) alignment process, once a first axis is aligned, an adjustment operation may be performed for another axis (e.g., axis C shown in fig. 8). Thus, in operation, the disclosed leveling alignment method can begin with securing one of the planes and then tilting the array in the other plane until the array is in leveling alignment with the substrate.

According to at least one embodiment, the automatic alignment process may begin to quickly reach the semi-aligned position as follows: a rough tilt operation is performed at the beginning of the alignment process. For example, the initial alignment may be performed at relatively large tilt increments of 0.05 ° to quickly and efficiently reach a quasi-leveled alignment state. Subsequently, the two-step leveling alignment operation may be repeated in small increments (e.g., 0.001 °). In such an embodiment, once the semi-aligned position has been reached, the adjustment of the positioning by operation may be performed with a smaller tilting operation.

The criteria for leveling alignment may be a short circuit of the circuitry on the opposite side of the probe array for the electrical contact method. Subsequently, the aligned planes may be fixed, and the same process may be performed on the planes that are not aligned yet.

FIG. 9 illustrates a series of operations involved in a method for automatically aligning a probe array provided in accordance with at least one disclosed embodiment. As shown in fig. 9, a lithographic fabrication operation begins at 700, and as disclosed herein, a probe array is positioned within an array holder at 705. Once the probe array is positioned in the holder and the substrate is positioned relative to the probe array (by conventionally known mechanisms), the self-alignment process begins by applying voltages to the four corner regions and grounding the four side center regions (or vice versa) at 710. The application of these voltage levels enables the configuration of four independent circuits.

Thus, it should be understood that, according to at least one embodiment, the self-alignment method may be performed automatically in response to one or more sensors detecting that the probe array has been loaded into the holder. Alternatively, the method may be performed in response to initiating an auto-alignment method based on external data (e.g., user initiated, initiated in response to instructions of other manufacturing components, etc.). The disclosed embodiments enable alignment to be performed in an automated manner without requiring monitoring and input by a user as part of the alignment process.

Operation then proceeds to 715 where the relative positioning of the array and substrate is repeatedly performed at 715, for example by moving the array and/or substrate relative to each other in specified increments (e.g., increments of 0.05-0.001 (including 0.05 and 0.001)), and the presence and level values of the current for each of the four circuits are measured at 720. For example, by detecting the currents flowing in all four circuits, the contact points of the tips at the four corners with the substrate can be reliably identified in an unbonded or independent manner. Accordingly, operations 715, 720 may be performed repeatedly until it is determined that current is detected at two or more circuits at 725. Once this determination is complete, the operation proceeds to 730, alignment ends at 730 and the lithography operation begins. As will be appreciated by one of ordinary skill in the art, operations 715, 720 may be performed in a manner consistent with fig. 6 and the associated description.

Subsequent nanopatterning, nanoprinting, or other lithographic operations may be performed after determining that the two or more circuits detected current at 725.

FIG. 10 illustrates a functional diagram showing a lithography machine 140 including a self-alignment mechanism provided in accordance with the disclosed embodiments. Note that fig. 8 illustrates the operation and cooperation of the components of such a lithography machine 140, with particular reference to the novel and innovative array alignment mechanism disclosed herein. Accordingly, a detailed description of conventionally available and conventionally understood photolithography, nanofabrication, nanoimprinting, and nanopatterning techniques is not provided herein, as this is within the level of skill of one of ordinary skill in the art.

Thus, in summary, the lithography machine 140 shown in fig. 10 may comprise a self-aligning device 145 and a substrate holder 150 (in implementations where the array is moved and the substrate is held stationary, the device comprises a substrate table to hold the substrate). It should be noted that the self-alignment method disclosed herein may be performed by moving the substrate relative to the fixed array 100; accordingly, configurations of such embodiments are also within the scope of the disclosed embodiments.

The alignment device 145 may include at least oneA plurality of, and optionally more than one, motorized translation stage 155, such as a tip/tilt stage on which the array holder 115 is mounted, and a controller 160. Thus, the array holder 115 may be mounted in a motorized tilt/tilt table 155, which tilt/tilt table 155 may tilt the array 100 in two orthogonal planes in the smallest increment possible (e.g., 4 x 10 as described herein)^-5Increments of degrees). The substrate holder 150 and the auto-alignment device 145 may be positioned under the control of the controller 160. The controller 160 may be part of the device 145 or coupled to the device 145. The controller 160 may also optionally control the operation of one or more lithographic fabrication modules 165 to perform lithography, nano-fabrication, nano-patterning, and/or nano-printing. Such lithographic fabrication techniques are within the skill level of one of ordinary skill in the art. For example, currently known such lithographic fabrication techniques and later developed techniques are used for direct molecular printing, such as PPL or BPL.

Thus, the actuators included in the stage 155 can be used to provide control of the components shown in fig. 8 and associated movement, enabling movement of the apparatus and monitoring of the current to determine contact/non-contact of the array and the area of the substrate. Advantageously, this configuration may enable automation of the leveling alignment process, thereby eliminating an otherwise cumbersome process.

It is noted that particular technical utility is provided by the disclosed components, apparatus and methods, as only one analog output is required to apply a voltage bias and four analog inputs are required to read current in accordance with at least one disclosed embodiment. Furthermore, due to the low impedance of the system, only low voltages of less than 10V are required to generate a measurable current. Such an implementation enables implementation using low cost DAQ devices.

As proof of technical utility of the presently disclosed embodiments, according to at least one disclosed embodiment, the self-alignment process may be based on electrical contact feedback that enables leveling alignment of the elastomeric probe array with the substrate to 0.005 ° in a repeatable and reliable manner in an average of less than ten minutes. Furthermore, the utility of the method is not strictly limited to the original elastomeric pen array, but is also applicable to polymer pen arrays having a layer of hard material as well as pen arrays made only of hard material.

As another proof of the technical utility of the presently disclosed embodiments, it should be appreciated that conventionally known optical alignment techniques cannot achieve leveling alignment accuracy better than 0.02 °. Additionally, it should be appreciated that the presently disclosed electrical contact leveling alignment strategy provides a cost effective and faster alternative to conventional approaches. Additionally, the presently disclosed electrical contact leveling alignment strategy eliminates the conventional need for tip deformation as used in force alignment methods. As such, the presently disclosed embodiments can be used for leveling alignment even when the tips of the array are coated with a hard material (e.g., Au or Al in BPL experiments), which can cause complexity of the leveling alignment when using conventional force alignment methods.

While certain illustrative embodiments have been described, it is evident that many alternatives, modifications, permutations and variations will become apparent to those skilled in the art in light of the foregoing description. While illustrative embodiments have been outlined above, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

For example, although the disclosed embodiments have been described with respect to fabricating contacts on the probe array and applying voltage bias and ground to the probe array, where the substrate plays a passive role in the motion of the array relative to the substrate, the movement of the array and substrate may be reversed, e.g., the substrate may be moved relative to a fixed array. Thus, the same principle applies to the case where contacts are created on the substrate and voltage and ground are applied to the substrate while the probe array plays a passive role (simply shortening the electrically opposing area).

Furthermore, the voltage and the grounding position, indicated by +, -symbols in the figures, can be switched with the same effect, the occurrence of which enables the measurement of the current flowing due to the application of the voltage to the areas in contact with each other.

Thus, as mentioned above, the various embodiments of the present invention are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.

It will therefore be evident to a person skilled in the art that the described illustrative embodiments are only examples and that various modifications may be made within the scope of the invention as defined in the appending claims.

Claims (10)

1. A lithography machine, comprising:

an array of probes; and

a mechanism for positioning the probe array or substrate relative to each other to automatically align the probe array and the substrate parallel to each other for subsequent lithographic fabrication, wherein a plurality of components are to be fabricated by lithography on the substrate.

2. The lithography machine of claim 1, wherein said mechanism comprises a motorized tilt/tilt stage coupled to said probe array or said substrate, said tilt/tilt stage enabling tilting of said probe array or said substrate in two orthogonal planes.

3. The lithography machine of claim 1, wherein said self-alignment applies a voltage bias to said probe array or said substrate to induce a measurable current to indicate electrical contact between a region of said substrate and a corresponding region of said probe array.

4. The lithography machine of claim 1, wherein said self-alignment forms a circuit capable of carrying current.

5. The lithography machine of claim 1, wherein said self-aligning comprises: repeated control of the probe array or the substrate and movement relative to each other is performed while measuring current between the probe array and corresponding conductive regions of the substrate.

6. The lithography machine of claim 1, wherein said automatic alignment positions said probe array or said substrate such that said probe array and said substrate are positioned within 0.005 ° parallel to each other in less than ten minutes.

7. The lithography machine of claim 1, wherein the probe array is one of a cantilevered scanning probe array, a polymer pen/probe array, or a beam pen/probe array.

8. The lithography machine according to claim 1, wherein the lithography machine is a polymer pen lithography machine and the probe array comprises a large number of probes arranged in parallel, each probe serving as a point source for direct molecular printing.

9. The lithography machine according to claim 1, wherein the lithography machine is a beam pen lithography machine and the probe array comprises a large number of parallel arranged probes for performing diffraction-free patterning with light.

10. The lithography machine according to claim 1, wherein said lithography is cantilever-less scanning probe lithography.

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