Method for producing at least one microfluidic receiving element, method for using the microfluidic receiving element, microfluidic receiving element, substrate for processing fluids with the microfluidic receiving element

Abstract

The approach presented here relates to a method (500) for producing at least one microfluidic receiving element (110). The method (500) comprises a step (505) of providing a substrate (100) which is provided, in particular, with at least one recess (115) and / or a sensitive layer. Furthermore, the method (500) comprises a step (515) of introducing at least one predetermined breaking point (205) into the substrate (100). Finally, the method (500) comprises a step (535) of breaking the substrate (100) at the at least one predetermined breaking point (205) in order to produce the at least one microfluidic receiving element (110).

Description

State of the art

[0001] The approach presented here is based on a method for producing at least one microfluidic receiving element, a method for using the microfluidic receiving element, a microfluidic receiving element, and a substrate for processing fluids with the microfluidic receiving element according to the preamble of the independent claims. The approach presented here also relates to a computer program.

[0002] For cost-effective, high-volume production of microsystems, large-area substrates with lateral dimensions in the range of several inches (in particular, 4 inches to 12 inches) can be used, enabling highly parallelized and standardized batch production. However, after such wafer-level production, it may often be necessary to separate the substrates into chips. Various dicing methods can be used for this purpose, such as laser-based dicing, i.e., laser-based breaking or cutting—so-called stealth dicing—mechanical sawing of the wafers, scoring the wafers with a diamond cutter and (subsequent) breaking the wafers, or structuring and (subsequent) grinding the wafers to a specified thickness.

[0003] For certain chips and / or microsystems, an exposed surface during the singulation process is desirable, for example, biological or chemical sensors, where a surrounding medium, particularly air or a liquid, is intended to come into contact with the chip surface (later) to achieve a desired functionality. For the functionality of such sensors, a clean, undamaged, functional surface is desirable even after singulation. Examples of such sensors include gas sensors or microfluidic sensors for analyzing a sample liquid. Disclosure of the invention

[0004] Against this background, the approach presented here provides a method for producing at least one microfluidic receiving element, a method for using the microfluidic receiving element, a microfluidic receiving element, and a substrate for processing fluids with the microfluidic receiving element, as well as a control device that uses one of these methods, a corresponding computer program, and finally, a corresponding machine-readable storage medium according to the main claims. The measures listed in the dependent claims enable advantageous refinements and improvements of the method specified in the independent claim.

[0005] A method for producing at least one microfluidic receiving element is presented. The method comprises a step of providing a substrate, in particular provided with at least one recess and / or a sensitive layer, a step of introducing at least one predetermined breaking point into the substrate, and a step of breaking the substrate at the at least one predetermined breaking point in order to produce the at least one microfluidic receiving element.

[0006] The predetermined breaking point can alternatively be described as pre-damage or “artificially created defect”.

[0007] The introduction of the predetermined breaking point can also be referred to as predetermined breaking point introduction, predetermined breaking point introduction or predetermined breaking point introduction process.

[0008] In particular, the substrate can have at least one recess for receiving a sample liquid and / or a sensitive layer for carrying out an analytical reaction with a sample liquid.

[0009] The approach presented here is based on the realization that by introducing predetermined breaking points, different microfluidic recording elements that were produced on a common substrate can be separated in a technically very simple and material-friendly manner by breaking them.

[0010] According to one embodiment, at least one further predetermined breaking point can be introduced into the substrate during the introduction step. In particular, the further predetermined breaking point can be introduced into the substrate at a different depth than the current predetermined breaking point. It is conceivable to introduce pre-damage of varying degrees on a wafer by introducing multiple predetermined breaking points within a single process step. This allows defined (and more severely pre-damaged) areas of the substrate to be removed directly at an earlier point in time by applying a small amount of force or without any force, while other areas can only be removed after subsequent processes. This enables structuring of the substrate – for example, changing its shape from round to square – while simultaneously pre-damaging it for later chip singulation within a single process step.This embodiment can also simplify the subsequent breaking step, enable any shape of the structures to be separated, independent of, for example, the crystal orientation of the substrate, and promote the quality of the breaking process by allowing a straighter, cleaner, and more controlled fracture edge on the substrate. By selecting the vertical positions and number of defects and / or predetermined breaking points, the fracture behavior can be adapted to a separation tool.

[0011] According to a further embodiment, the step of introducing the predetermined breaking point into the substrate can be carried out using a laser device, in particular an infrared laser. The introduction step can be carried out, for example, using a laser-based dicing method, in particular stealth dicing. The stealth dicing process can, in principle, function as follows: A (for example, fully processed) silicon wafer, or Si wafer for short, can be laminated and / or bonded to a dicing foil. Using at least one pulsed infrared laser beam, defects can (subsequently) be introduced into the silicon substrate by local melting. The dicing foil can be expanded, i.e., widened, to generate a gap between the individual chips. The adhesive strength of the foil can be reduced—for example, by UV exposure.Now (in a final step) the chips can be picked from the foil. Stealth Dicing enables the introduction of varying degrees of pre-damage, also known as defects, into the substrate, allowing the breaking force and / or stability of the substrate to be adjusted and controlled. This allows defined (and more severely pre-damaged) areas of the substrate to be removed at an earlier stage by applying a low force, or without the application of force directly through targeted, more severe damage, e.g., using a laser, while other areas can only be removed after subsequent processes. This enables the substrate to be structured - for example, changing its shape from round to square - while simultaneously pre-damaging it for later chip separation within a single process step.

[0012] According to one embodiment, the focusing and / or power control of the laser device can be varied and / or be variable during the introduction step. The introduction of the predetermined breaking points can be carried out, for example, using stealth dicing. The breaking force and / or stability of the wafer can be influenced, for example, by the laser power. A lower laser power can lead to smaller or less severe defects in the wafer and thus to greater wafer stability. The breaking force and / or stability of the wafer can also be influenced, for example, by the vertical position of the defects, which is determined in particular by the focal plane of a laser pulse, whereby defects located closer to the edge reduce the stability of the substrate.The breaking force and / or stability of the wafer can, for example, also be influenced by a number of defects, in particular in a horizontal direction via a frequency of the laser pulses and / or in a vertical direction via a number of laser passes at the same location with different focal planes. Fewer defects in the wafer can ensure greater wafer stability. The breaking force and / or stability of the wafer can, for example, also be influenced by the shape of the defects, such as a point-like or elongated shape. The shape of the defects can be controlled via the focus of the laser. By selecting the vertical positions of the defects and / or predetermined breaking points, the breaking behavior can be adapted to a singulation tool. It is conceivable to introduce varying degrees of pre-damage to a wafer by introducing several predetermined breaking points within a single process step.This allows defined (and more severely damaged) areas of the substrate to be removed at an earlier stage by applying a low force, while other areas can be removed only after subsequent processes. This enables structuring of the substrate—for example, changing its shape from round to square—while simultaneously pre-damaging it for later chip separation within a single process step.

[0013] According to an additional embodiment, the introduction step can be carried out such that the at least one predetermined breaking point is introduced on a side of the substrate opposite the recess and / or the sensitive layer or on the same side of the substrate as the recess and / or the sensitive layer, in particular next to the recess and / or the sensitive layer. By selecting vertical positions of the defects and / or predetermined breaking points, a breaking behavior can be adapted to a singulation tool. It is conceivable to introduce pre-damage of varying degrees on a wafer by introducing several predetermined breaking points within a single process step. This allows defined (and more severely pre-damaged) areas of the substrate to be removed at an earlier point in time by applying a low force, and other areas only after subsequent processes.This allows the substrate to be structured – for example, changing its shape from round to square – while simultaneously pre-damaging it for later chip separation within a single process step.

[0014] According to one embodiment, in a coating step, the recess can be coated with a layer, in particular with a biological and / or chemical layer. Such a layer can also be referred to as a surface modification layer or as surface functionalization. In particular, the coating step can be carried out after the step of introducing the pre-damage and / or before the breaking step. According to such an embodiment, alternatively or additionally, in a providing step, the at least one recess and / or the sensitive layer can be provided with a reagent, in particular with a biological and / or chemical reagent, for carrying out a biochemical analysis process. In particular, the providing step can be carried out before the breaking step and / or after the step of introducing the pre-damage.In principle, the further process steps possible according to embodiments after the introduction of the predetermined breaking point and before the separation—in particular, the application of the organic functional layer and / or the other layer and / or the spotting of the biological reagent—are likely to be limited only by the mechanical force applied. A process flow according to an embodiment, in which the coating step is carried out after the introduction step and / or before the breaking step, can be advantageous for the deposition of sensitive biological or chemical layers and / or reagents, for example, functional layers of a gas sensor or a biological sensor, surface modification layers, which can, for example, adjust the wettability of the surface—for example, toward hydrophilicity—or reduce adhesions—in particular of proteins.Furthermore, in the process of the approach presented here, according to one embodiment, ideally neither surface functionalization nor spotted reagents are exposed to the predetermined breaking point introduction process, since the surface functionalization and / or spotting of the reagents according to this embodiment takes place after the introduction of the predetermined breaking points. Thus, in the best case, the surface functionalization and / or the reagents are not damaged. This allows the chip to deliver improved performance in a subsequent biological application.

[0015] According to an additional embodiment, a surface of the substrate can be cleaned in a cleaning step. In particular, the cleaning step can be carried out after the introduction step and / or before the coating step and / or before the breaking step. An advantage over a conventional, similar method can be achieved by enabling effective cleaning after the introduction of the predetermined breaking points. Possible outgassing and / or other contaminants from the process of introducing the predetermined breaking points can be easily and conveniently cleaned off at such a stage. This may not be possible conventionally, at least not on large-area and not yet singulated substrates, which enables large-volume batch processes. This enables the chip to deliver improved performance in a later biological application of the chip.This embodiment is furthermore advantageous because the cleaning cannot attack any already existing chemical or biological surface functionalization, because according to this embodiment the cleaning step can be carried out before the coating step.

[0016] According to one embodiment, a tensile force can be applied to the surface of the substrate in the breaking step. In particular, the tensile force can be applied to the surface facing the predetermined breaking point. In order for the Si wafer to break in a controlled manner, a tensile force can, for example, be introduced into the surface of the wafer on which the defects are located. According to embodiments, the predetermined breaking points and / or defects can be or have been introduced on a wafer backside and / or on a wafer frontside. The wafer can (then) be singulated, for example, by mechanical breaking by applying a tensile force, e.g., by bending. This embodiment enables advantageous singulation of the wafer by breaking and with the aid of an effect of the tensile force on the wafer, wherein this tensile force can cause the wafer to break.According to such an embodiment, a breaking process of the wafer by means of a tensile force ideally leads to no further impairment of the chip, except possibly to blow-off Si particles.

[0017] According to a further embodiment, the provision step can include a step of forming a recess or cavity and / or the sensitive layer on the surface of the substrate. In this case, the forming step can be performed, in particular, before the insertion step. This embodiment is advantageous in that the formation of such a recess enables the (subsequent) provision of the recess with a reagent for carrying out a biochemical analysis process. This allows the chip to provide advantageous performance in a subsequent biological application of the chip.

[0018] Furthermore, a method for using a variant of the previously presented microfluidic receiving element is presented. The method comprises a step of introducing an aqueous solution, i.e., a sample solution, into at least one recess of the receiving element and a step of detecting a parameter of a reaction carried out in the receiving element using the introduced aqueous solution. This embodiment is advantageous in that the chip can provide advantageous performance in a subsequent biological application of the chip. This embodiment, in the form of a method, also allows the problem underlying the approach presented here to be solved quickly and efficiently.

[0019] These methods can be implemented, for example, in software or hardware or in a mixture of software and hardware, for example in a control unit.

[0020] Furthermore, a microfluidic receiving element is presented, which, according to one embodiment, can have a breaking edge through at least one predetermined breaking point on a lateral edge of the microfluidic receiving element. This embodiment variant in the form of a receiving element also allows the problem underlying the approach presented here to be solved quickly and efficiently.

[0021] Furthermore, a microfluidic device for processing fluids using the microfluidic receiving element is presented. This design variant, in the form of a microfluidic device, also allows the task underlying the approach presented here to be solved quickly and efficiently.

[0022] The approach presented here further creates a control unit configured to execute and / or control the steps of a variant of a method presented here in corresponding units. This variant in the form of a control unit also allows the task underlying the approach presented here to be solved quickly and efficiently.

[0023] For this purpose, the control unit can have at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading sensor signals from the sensor or for outputting control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a microcontroller, or the like, wherein the memory unit can be a flash memory or a magnetic storage unit.The communication interface can be designed to read in or output data wirelessly and / or wired, wherein a communication interface that can read in or output wired data can read this data, for example, electrically or optically from a corresponding data transmission line or output it to a corresponding data transmission line.

[0024] In this context, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals depending on them. The control unit can have an interface that can be implemented in hardware and / or software. In a hardware implementation, the interfaces can, for example, be part of a so-called system ASIC, which contains a wide variety of functions of the control unit. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

[0025] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer or a device.

[0026] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows: Fig. 1 a schematic cross-sectional view of a substrate of a microfluidic receiving element according to an embodiment; Fig. 2a a schematic cross-sectional view of a substrate of a microfluidic receiving element according to an embodiment; Fig. 2b shows a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element with a plurality of recesses; Fig. 2c a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element as shown in Fig. 2b, with a plurality of predetermined breaking points; Fig. 2d a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element as shown in Fig. 2c, with a layer on the substrate; Fig. 2e a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element as shown in Fig. 2d, with a reagent in the plurality of recesses; Fig. 2f is a schematic cross-sectional view of an embodiment of a plurality of microfluidic receiving elements, which can be formed, for example, by breaking a substrate, as shown in Fig. 2e; Fig. 3 is a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element being broken by a breaking device; Fig. 4a is a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element having a plurality of predetermined breaking points; Fig. 4b is a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element having a plurality of predetermined breaking points; Fig. 4c is a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element having a plurality of predetermined breaking points; Fig. 4d is a schematic cross-sectional view of an embodiment of a substrate of a microfluidic receiving element having a plurality of predetermined breaking points; Fig. 5 is a flowchart of an embodiment of a method for producing a microfluidic receiving element; Fig. 6 is a flowchart of an embodiment of a method for using a microfluidic receiving element; Fig. 7 a schematic representation of a control device according to an embodiment; and Fig. 8 a schematic representation of a control unit according to an embodiment.

[0027] In the following description of advantageous embodiments of the approach presented here, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0028] Fig. 1 shows a schematic cross-sectional view of a substrate 100 of a microfluidic receiving element 110 according to one embodiment. The substrate 100 is designed to process fluids and thus, for example, substances dissolved in a fluid. For this purpose, the substrate 100 comprises the microfluidic receiving element 110, which in this embodiment is arranged on a flow cell 105 and can be embedded in a microfluidic device 112. The receiving element 110 has a recess 115 for receiving an aqueous solution, i.e., a sample liquid.

[0029] In this exemplary embodiment, the receiving element 110 comprises, merely by way of example, in addition to the recess 115, a second recess 135, as well as, merely by way of example, a third recess 140, a fourth recess 142, a fifth recess 144 and a sixth recess 146, wherein all recesses 115, 135, 140, 142, 144, 146 are arranged in a plane of an upper side 130 of the receiving element 110, and wherein all recesses 115, 135, 140, 142, 144, 146 are identical to one another in shape and size.

[0030] The illustrated receiving element 110 or a similar receiving element is an important component of microfluidic analysis systems such as the microfluidic device 112. Small reaction chambers of the receiving element 110, i.e., the recesses 115, 135, 140, 142, 144, 146, can accommodate the fluid to be analyzed.

[0031] Fig. Figure 2a shows a schematic cross-sectional view of a substrate 100 of a microfluidic receiving element according to an embodiment. In other words, Fig. 2a shows, merely by way of example, a provided Si wafer or in other words a substrate 100 for processing fluids with the Fig. 1 or a similar receiving element. A surface 200 of the substrate 100 does not have Fig. 1 and the recesses described in more detail in the following figures.

[0032] Fig. Figure 2b shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element with a plurality of recesses 115. The plurality of recesses 115 are arranged on the surface 200 of the substrate 100. This Fig. 2b accordingly shows a substrate 100 provided with a plurality of recesses 115. For example only, the substrate 100 comprises three recesses 115 arranged next to one another, which are identical or similar in shape and / or size, for example. Material of the substrate 100 is arranged between the recesses 115, each as a type of wall and / or spacer and / or spatial separation of the recesses 115.

[0033] According to one embodiment, the substrate 100 may be the Fig. 2a, on whose surface 200 the plurality of recesses 115 is or has been formed.

[0034] In other words, Fig. 2b shows an exemplary embodiment of a pre-process on the wafer, in particular the illustrated structuring, i.e. the formation of the plurality of recesses 115 on the surface 200 of the substrate 100. In Fig. In other words, Figure 2b shows an embodiment of a pre-process, here using the example of structuring - also called structuring.

[0035] According to a further embodiment, the substrate 100 may not be the one shown in Fig. 2a, but rather a similar substrate in whose surface 200 the plurality of recesses 115 are (already) formed.

[0036] Fig. Figure 2c shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element, as shown in Fig. 2b, with a plurality of predetermined breaking points 205. According to one embodiment, the substrate 100 may be the one shown in Fig. 2a and / or the Fig. 2b. A plurality of recesses 115 are arranged on the surface 200 of the substrate 100. These Fig. 2c accordingly shows a substrate 100 provided with a plurality of recesses 115. For example only, the substrate 100 may comprise three recesses 115 arranged next to one another, which are identical or similar in shape and / or size, for example. Material of the substrate 100 is arranged between the recesses 115 as a type of wall and / or spacer and / or spatial separation of the recesses 115.

[0037] The substrate 100 has a plurality of predetermined breaking points 205. According to one embodiment, the substrate 100 can comprise eight predetermined breaking points 205, of which two predetermined breaking points 205 are arranged at a respective at least approximately adjacent and / or close position to one another and / or next to one another and / or one above the other in an axis perpendicular to the surface 200 of the substrate 100 within a tolerance range. According to embodiments, two predetermined breaking points 205 can be arranged at a respective lateral and / or transverse and / or longitudinal edge of the substrate 100 and additionally or alternatively between or next to the recesses 115 in an axis perpendicular to the surface 200 of the substrate 100 within a tolerance range. It is also conceivable that a plurality of recesses 115 can be located between two predetermined breaking points 205.

[0038] In the case of the respectively connected pairs of predetermined breaking points, each of which comprises a predetermined breaking point 205 and a further predetermined breaking point 210, the respective further predetermined breaking point 210 can, for example, be or will be introduced into the substrate 100 at a different depth than the respective associated predetermined breaking point 205.

[0039] According to one embodiment, the predetermined breaking points 205, 210 - as in this Fig. 2c - on a side of the substrate 100 opposite the recess 115 or - as not shown in this Fig. 2c - on the same side of the substrate 100 as the recess 115.

[0040] According to one embodiment, the introduction of the predetermined breaking points 205, 210 can be carried out in such a way that the wafer with the predetermined breaking points 205, 210 remains stable enough for further processing on the one hand, but on the other hand, a separation of the wafer into chips is possible at any time by applying sufficient force.

[0041] According to a further embodiment, the predetermined breaking points 205, 210 can be introduced into the substrate 100 using a laser device 215, in particular an infrared laser such as stealth dicing—schematically represented by black dots. The stealth dicing process can, in principle, function as follows: A fully processed silicon wafer, or Si wafer for short, can be laminated and / or bonded to a dicing foil. Defects can be introduced into the silicon substrate by local melting using at least one pulsed infrared laser beam. Conventionally, the wafer can break into individual chips along the introduced defects. The dicing foil can be expanded, i.e., widened, to generate a gap between the individual chips. The adhesive strength of the foil can be reduced—for example, by UV exposure.Now (in a final step), the chips can be picked from the foil. According to this exemplary embodiment, the introduction of the predetermined breaking points 205, 210 into the substrate 100 can thus be carried out via stealth dicing. A breaking force and / or stability of the wafer can be influenced, for example, by a laser power. In other words, during stealth dicing, for example, a power control of the laser device 215 can be varied and / or be variable. In this case, a lower laser power can lead to smaller defects in the wafer and thus to greater wafer stability. The breaking force and / or stability of the wafer can also be influenced, for example, by a vertical position of the defects, which is determined in particular by a focal plane of a laser pulse. In other words, during stealth dicing, a focus of the laser device 215 can be varied and / or be variable.

[0042] The breaking force and / or stability of the wafer can also be influenced, for example, by a number of defects, in particular in a horizontal direction via a frequency of the laser pulses and / or in a vertical direction via a number of laser passes at a same location with different focal planes. Fewer defects in the wafer can ensure greater stability of the wafer. The breaking force and / or stability of the wafer can also be influenced, for example, by the shape of the defects, for example, a point-like or elongated shape. The shape of the defects can be controlled via a focus of the laser. As already mentioned above, the focus of the laser device 215 can be varied and / or be variable during stealth dicing. The partial figures of the Fig. 4 shows such exemplary defects in cross-sectional representations, also called transverse fractures. By selecting the vertical positions of the defects and / or predetermined breaking points 205, 210, the fracture behavior can be adapted to a separation tool.

[0043] Fig. Figure 2d shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element, as shown in Fig. 2c, with a layer 220 on the substrate 100. A plurality of recesses 115 are arranged on the surface 200 of the substrate 100. This Fig. 2d accordingly shows a substrate 100 provided with a plurality of recesses 115. For example only, the substrate 100 comprises three recesses 115 arranged next to one another, which are identical or similar in shape and / or size, for example. Material of the substrate 100 is arranged between the recesses 115 as a type of wall and / or spacer and / or spatial separation of the recesses 115.

[0044] According to one embodiment, the surface 200 of the substrate 100 can be cleaned. In particular, such cleaning of the surface 200 of the substrate 100 can be performed after the predetermined breaking points 205, 210 have been introduced into the substrate 100. Cleaning after the predetermined breaking points have been introduced can be performed, for example, by plasma cleaning (O2, H2O, N2, Ar, CF4, etc.) or wet cleaning (RCA, HF, etc.) or in a vapor phase (water + H2O2, isopropanol).

[0045] According to a further embodiment, the recesses 115 can be coated with the layer 220. In particular, such coating of the recesses 115 can be performed after the surface 200 of the substrate 100 has been cleaned.

[0046] In other words, Fig. 2d the cleaning of the wafer and the application of a layer 220, for example an organic functional layer - shown in blue - which has or may have special cleanliness requirements, and / or the application of another layer which has or may have special cleanliness requirements.

[0047] In particular, this can Fig. 2d illustrates cleaning and coating of the substrate 100 after introducing the predetermined breaking points 205, 210 and / or before the subsequent Fig. 2f described in more detail breaking the substrate.

[0048] Fig. Figure 2e shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element as shown in Fig. 2d, with a reagent 225 in the plurality of recesses 115. The plurality of recesses 115 are arranged on the surface 200 of the substrate 100. This Fig. 2e accordingly shows a substrate 100 provided with a plurality of recesses 115. For example only, the substrate 100 comprises three recesses 115 arranged next to one another, which are identical or similar in shape and / or size, for example. Material of the substrate 100 is arranged between the recesses 115, each as a type of wall and / or spacer and / or spatial separation of the recesses 115.

[0049] According to one embodiment, the recesses 115 can be provided with the reagent 225 for carrying out a biochemical analysis process. In other words, this Fig. 2e an optional spotting of, for example, biological reagent 225.

[0050] In particular, this can Fig. 2e illustrates providing the recesses 115 with the reagent 225 after the introduction of the predetermined breaking points 205, 210 and / or before the following Fig. 2f described in more detail breaking the substrate.

[0051] The Fig. 2d and Fig. In other words, Figure 2e shows further process steps on the wafer—in particular, cleaning steps, steps for applying organic layers or other layers, and spotting biological reagents. In principle, the further process steps possible according to embodiments after the introduction of the predetermined breaking points and before dicing—i.e., in particular, cleaning the wafer and / or applying layer 220, for example, the organic functional layer and / or the other layer, and / or spotting the biological reagent 225—are likely limited only by an applied mechanical force.

[0052] A process flow according to an embodiment in which the Fig. 2d described step of cleaning and / or the step also described in Fig. 2d described step of coating according to the Fig. 2c described step of introduction and / or before the following in Fig. 2f, can be advantageous for depositing sensitive biological or chemical layers and / or reagents 225, merely by way of example functional layers of a gas sensor or a biological sensor, surface modification layers which can, for example, adjust a wettability of the surface 200 - for example, in the direction of hydrophilicity - or reduce adhesions - in particular of proteins.

[0053] Fig. Fig. 2f shows a schematic cross-sectional view of an embodiment of a plurality of microfluidic receiving elements 110, which are formed, for example, by breaking a substrate 100, as shown in Fig. 2e. A plurality of recesses 115 are arranged on the surface 200 of the substrate 100. These Fig. 2f accordingly shows a substrate 100 provided with a plurality of recesses 115. For example only, the substrate 100 comprises three recesses 115 arranged next to one another, which are identical or similar in shape and / or size, for example. Material of the substrate 100 is arranged between the recesses 115, each as a type of wall and / or spacer and / or spatial separation of the recesses 115.

[0054] According to one embodiment, the substrate 100 can be broken at the predetermined breaking points 205, 210 in order to produce individual microfluidic receiving elements 110. In other words, this Fig. 2f a mechanical breaking of the wafer into chips, for example by means of a suitable automated and subsequently Fig. 3 described in more detail. In other words, Fig. 2f separation into chips by mechanical breaking.

[0055] According to one embodiment, during breaking, a Fig. 3 can be applied to the surface 200 of the substrate 100. In particular, the tensile force can be applied to the surface 200 facing the predetermined breaking points 205, 210.

[0056] Examples in this Fig. 2f illustrates three microfluidic receiving elements 110. The microfluidic receiving elements 110 each have a break edge 230 at their respective lateral edges.

[0057] In summary, it can be said that the subfigures of the Fig. 2 show a possible overall process flow according to an embodiment.

[0058] Fig. 3 shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element, which is broken by a breaking device 300.

[0059] In other words, in Fig. 3 shows a sketch of a possible tool for breaking the Si wafers with predetermined breaking points in chips.

[0060] In other words, Fig. 3 shows a mechanical breaking of the wafer into chips, for example by means of the breaking device 300, which should be suitable and can be automated, for example. The breaking device 300 can also be called a singulation tool or breaking tool. In other words, Fig. 3 separation into chips by mechanical breaking.

[0061] According to one embodiment, a tensile force 305 can be applied to the surface 200 of the substrate 100, i.e., the wafer, during breaking. In particular, the tensile force 305 can be applied to the surface 200 facing the predetermined breaking points 205.

[0062] By selecting the vertical positions of the predetermined breaking points 205 – also called defects or pre-damage – the breaking behavior can be adapted to the breaking device 300. In order to break the Si wafer in a controlled manner, a tensile force 305 can be applied to the surface of the wafer where the predetermined breaking points 205 are located. Fig. 3 shows an embodiment of a structure around a wafer in which the predetermined breaking points 205 were introduced on a wafer backside, i.e., on a substrate backside. The wafer can then be separated, for example, by mechanical breaking. According to this embodiment, a blade or a punch can press against a wafer frontside, in particular at the locations where defect lines are introduced. A flexible base 310, such as a rubber mat, can be located beneath the wafer, for example. Thus, the tensile force 305 can act on the wafer backside, and the wafer can be separated by breaking. Instead of the flexible base 310, a rigid base could also be used, which, for example, can have a recess directly beneath the blade or punch. According to further embodiments, other breaking tools and breaking methods are also conceivable, such as breaking by means of three-point bending.

[0063] According to one embodiment, the introduction of varying degrees of pre-damage to a wafer through the stealth dicing process is conceivable within a single process step. This allows, for example, defined (and more severely pre-damaged) areas of the substrate 100 to be removed at an earlier point in time by applying a small force, while other areas can be removed, for example, only after any subsequent processes. This enables structuring of the substrate 100—in particular, changing its shape from round to square—while simultaneously pre-damaging it for later chip singulation within a single process step.

[0064] The following sub-figures of the Fig. 4 show cross-sectional views through a silicon wafer, i.e., a substrate 100, after the introduction of the predetermined breaking points 205 and / or defects, for example, by stealth dicing. The three detailed enlargements Fig. 4b, Fig. 4c and Fig. 4d show only examples of three different wafer recipes and / or stealth dicing recipes.

[0065] Fig. Figure 4a shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element having a plurality of predetermined breaking points 205. According to one embodiment, a distance 400 between a substrate rear side 405 and a substrate front side 410 can be 380 micrometers. In a lower portion 415 of this Fig. 4a is an embodiment of a device shown in the following sub-figures of Fig. 4 described wafer recipe and / or stealth dicing recipe.

[0066] Fig. 4b shows a schematic cross-sectional view of an embodiment of a substrate 100 of a microfluidic receiving element having a plurality of predetermined breaking points 205. Shown is an embodiment of the lower portion 415 of the above-described Fig. 4a. According to this embodiment, the substrate 100 may have a defect row 420 having a plurality of predetermined breaking points and a further defect row 425, which also has a plurality of predetermined breaking points, near or at the substrate backside 405. For example, a distance 430 between the substrate backside 405 and a side of the further defect row 425 facing away from the substrate backside 405 may be 110 micrometers.

[0067] Fig. 4c shows a schematic cross-sectional view of an embodiment of a substrate 100 having a plurality of predetermined breaking points 205. Shown is an embodiment of the lower portion 415 of the above-described Fig. 4a. According to this embodiment, the substrate 100 may have a defect row 420 having a plurality of predetermined breaking points and a further defect row 425, which also has a plurality of predetermined breaking points, near or on the substrate backside 405, namely closer to the substrate backside 405 than in Fig. 4b. For example, a distance 435 between the substrate backside 405 and a side of the further defect row 425 facing away from the substrate backside 405 may be 50 micrometers.

[0068] Fig. 4d shows a schematic cross-sectional view of an embodiment of a substrate 100 having a plurality of predetermined breaking points 205. Shown is an embodiment of the lower portion 415 of the above-described Fig. 4a. According to this embodiment, the substrate 100 may have a defect row 420 having a plurality of predetermined breaking points and another defect row 425, which also has a plurality of predetermined breaking points, near or at the substrate front side 410. For example, a distance 440 between the substrate front side 410 and a side of the defect row 420 facing away from the substrate front side 410 may be 110 micrometers.

[0069] Fig. 5 shows a flowchart of an embodiment of a method 500 for producing a microfluidic receiving element. The method 500 comprises a step 505 of providing a substrate, in particular provided with at least one recess and / or a sensitive layer, a step 515 of introducing at least one predetermined breaking point into the substrate, and a step 535 of breaking the substrate at the at least one predetermined breaking point in order to produce the at least one microfluidic receiving element.

[0070] According to one embodiment, method 500 may include a step 510 of forming a recess and / or the sensitive layer on a surface of the substrate. In particular, this forming step 510 may be performed before the insertion step 515.

[0071] According to one embodiment, the method 500 may further comprise a step 520 of cleaning the surface of the substrate. In particular, the cleaning step 520 may be performed after the insertion step 515 and / or before a coating step 525 described below and / or before the breaking step 535.

[0072] According to a further embodiment, the method 500 may include a step 525 of coating the recess with a layer. In particular, this coating step 525 may be performed after the insertion step 515 and / or before the breaking step 535.

[0073] According to one embodiment, the method 500 may further comprise a step 530 of providing the at least one recess with a reagent for performing a biochemical analysis process. In particular, this step 530 of providing may be performed before the breaking step 535 and / or after the insertion step 515.

[0074] Alternatively, Fig. 5 a process flow for producing Si chips from a Si wafer with the following process steps: - Providing a Si wafer - Any pre-processes on the wafer, in particular structuring - i.e. forming a recess - and / or deposition - i.e. coating - Introduction of predetermined breaking points in such a way that the wafer with the predetermined breaking points remains stable enough for further processing on the one hand, but on the other hand, the wafer can be separated into chips at any time by applying sufficient force - Further process steps on the wafer - in particular cleaning steps, steps for applying organic layers, spotting of biological reagents - Mechanical breaking of the wafer into chips, for example by means of a suitable automated and above-mentioned Fig. 3 breaking device described in more detail.

[0075] An advantage over a conventional, similar method can be achieved by enabling effective cleaning after the introduction of the predetermined breaking points. Possible outgassing and / or residues and / or other contaminants from the process of introducing the predetermined breaking points can be easily and conveniently cleaned off at such a stage. This may not be possible conventionally. Furthermore, in the method of the approach presented here, according to one embodiment, ideally neither surface functionalization nor spotted reagents are exposed to the predetermined breaking point introduction process, since the surface functionalization and / or spotting of the reagents according to one embodiment of the present approach take place after the introduction of the predetermined breaking points and / or after the cleaning of the surface of the substrate.Ideally, this prevents damage to the surface functionalization and / or reagents. This allows the chip to perform better in future biological applications. Ideally, a wafer breakage process will not cause any further damage to the chip, except for potentially releasing Si particles.

[0076] In summary, it can be said that Fig. 5 shows a possible overall process flow, i.e. a method sequence, according to an embodiment.

[0077] Fig. 6 shows a flow diagram of an embodiment of a method 600 for using a microfluidic receiving element. The method 600 comprises a step 605 of introducing an aqueous solution into the at least one recess of the receiving element and a step 610 of detecting a parameter of a reaction carried out in the receiving element using the introduced aqueous solution.

[0078] Fig. Figure 7 shows a schematic representation of a control unit 700 according to an exemplary embodiment. The control unit 700 is configured to execute and / or control steps 505, 510, 515, 520, 525, 530, 535 of the method 500 in corresponding units 705, 710, 715, 720, 725, 730, 735.

[0079] The control device 700 comprises a unit 705 for carrying out and / or controlling the provision of a substrate provided with at least one recess, a unit 715 for carrying out and / or controlling the introduction of at least one predetermined breaking point into the substrate, and a unit 735 for carrying out and / or controlling the breaking of the substrate at the at least one predetermined breaking point in order to produce the at least one microfluidic receiving element.

[0080] According to one embodiment, the control device 700 may comprise a unit 710 for executing and / or controlling the formation of a recess on a surface of the substrate. In particular, this unit 710 for executing and / or controlling the formation of the recess may be executed and / or controlled before the unit 715 for executing and / or controlling the insertion.

[0081] According to one embodiment, the control device 700 may further comprise a unit 720 for performing and / or controlling the cleaning of the surface of the substrate. In particular, this unit 720 for performing and / or controlling the cleaning may be performed and / or controlled after the unit 715 for performing and / or controlling the introduction and / or before a unit 725 described below for performing and / or controlling the coating and / or before the unit 735 for performing and / or controlling the breaking.

[0082] According to a further embodiment, the control unit 700 may comprise a unit 725 for carrying out and / or controlling the coating of the recess with a layer. In particular, this unit 725 for carrying out and / or controlling the coating may be carried out and / or controlled after the unit 715 for carrying out and / or controlling the introduction and / or before the unit 735 for carrying out and / or controlling the breaking.

[0083] According to one embodiment, the control device 700 may further comprise a unit 730 for carrying out and / or controlling the provision of the at least one recess with a reagent for carrying out a biochemical analysis process. In particular, this unit 730 for carrying out and / or controlling the provision can be carried out and / or controlled before the unit 735 for carrying out and / or controlling the breaking and / or after the unit 715 for carrying out and / or controlling the introduction.

[0084] Fig. 8 shows a schematic representation of a control unit 800 according to an embodiment. The control unit 800 is configured to execute and / or control steps 605, 610 of the method 600 in corresponding units 805, 810. The control unit 800 comprises a unit 805 for executing and / or controlling the introduction of an aqueous solution into the at least one recess of the receiving element, as well as a unit 810 for executing and / or controlling the detection of a parameter of a reaction carried out in the receiving element using the introduced aqueous solution.

[0085] In summary, it can be noted that with conventional separation, cleanliness of the chip surface may not be guaranteed.

[0086] For example, during singulation using a conventional mechanical sawing process, sawing sludge can be generated, and the chip surface can be rinsed with water. The conventional alternative of covering the top of the wafer with a protective film during the sawing process can result in an adhesive film touching the sensitive chip surface, and if this film is removed, residues can be left on the chip surface. For example, this could result in residues of an adhesive used for bonding and / or mechanical damage to the surface, particularly film tears.

[0087] During stealth dicing, a dicing foil, to which the wafer may be attached during the stealth dicing process, could outgas, leaving residues, particularly chemical residues, on the chip surface. In addition to outgassing, a detachment process—for example, using UV light and / or heat—may also generate ozone, which can attack organic surface layers on the chip.

[0088] Scoring and subsequent breaking of the wafers can result in particles. Furthermore, in silicon, the direction of refraction can be determined by a crystal orientation.

[0089] For conventional grinding of the back side of the wafer, an adhesive film can be glued to the front side of the wafer, which could leave residues and / or possibly (also) mechanical damage on the chip surfaces when the adhesive film is removed.

[0090] Such residues and / or outgassing can, in particular, alter the fluidic properties of the chip surface or inhibit certain biological or chemical reactions. This could render the conventional chip unusable. Conventional subsequent cleaning at the chip level can be complex and expensive, as the process after singulation is usually a single-chip process. Conventional subsequent cleaning at the chip level may also be impractical, as cleaning could attack existing chemical or biological surface functionalization.

[0091] To overcome such challenges, the presented approach, according to one embodiment, creates a singulation method in which the cleanliness of the chip surface after singulation can be ensured or improved. Such a singulation method, which could also be referred to as a breaking method, can ideally leave organic surface layers present on the chip intact, according to one embodiment. This can promote the function of chemical and / or biological layers and thus of a sensor based thereon after singulation. Furthermore, with one embodiment of the presented approach, other surface properties, in particular fluidic properties, are (also) expected and / or desirably not changed by the singulation.

[0092] Since, in one embodiment of the approach presented, the wafers are cleaned after the predetermined break points have been introduced using stealth dicing, which can be directly detected, for example, in cross-sectional images of the break edges, conventional contamination and damage patterns left behind by the dicing foils are absent on the wafer surfaces. Surface analysis could detect very clean surfaces here, ideally without conventional contamination images. Since this feature represents one of the advantages of the disclosed approach, a competitor would not want to forego this feature, for example, for the purpose of "camouflage." From this, it can be concluded with a high degree of probability that the dicing process took place before cleaning and functionalization.

[0093] The approach presented here can alternatively be referred to as "process flow: predetermined breaking points -> process -> dicing" and, according to one embodiment, enables a combination of the mess-free introduction of predetermined breaking points using stealth dicing, followed by functionalization, followed by dicing. The approach presented here can be implemented, for example, in Si array chips for integration into a Vivalytic cartridge.

[0094] If an embodiment comprises an “and / or” link between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature and according to another embodiment has either only the first feature or only the second feature.

Claims

[1] Method (500) for producing at least one microfluidic receiving element (110), the method (500) comprising the following steps: Providing (505) a substrate (100) provided in particular with at least one recess (115) and / or a sensitive layer; Introducing (515) at least one predetermined breaking point (205) into the substrate (100); and Breaking (535) the substrate (100) at the at least one predetermined breaking point (205) in order to produce the at least one microfluidic receiving element (110). [2] Method (500) according to claim 1, wherein in the step (515) of introducing at least one further predetermined breaking point (210) is introduced into the substrate (100), in particular wherein the further predetermined breaking point (210) is introduced into the substrate (100) at a different depth than the predetermined breaking point (205). [3] Method (500) according to one of the preceding claims, wherein the step (515) of introducing the predetermined breaking point (205) into the substrate (100) is carried out using a laser device (215), in particular an infrared laser. [4] Method (500) according to claim 3, wherein in the step (515) of introducing a focus and / or a power control of the laser device (215) is varied and / or is variable. [5] Method (500) according to one of the preceding claims, wherein the step (515) of introducing is carried out such that the at least one predetermined breaking point (205) is introduced on a side of the substrate (100) opposite the recess (115) and / or the sensitive layer or on the same side of the substrate (100) as the recess (115) and / or the sensitive layer, in particular next to the recess (115) and / or the sensitive layer. [6] Method (500) according to one of the preceding claims, comprising a step (525) of coating the recess (115) with a layer (220), in particular wherein the step (525) of coating is carried out after the step (515) of introducing and / or before the step (535) of breaking and / or wherein a step (530) of providing the at least one recess (115) and / or the sensitive layer with a reagent (225) for carrying out a biochemical analysis process is provided, in particular wherein the step (530) of providing is carried out before the step (535) of breaking and / or after the step (515) of introducing. [7] Method (500) according to one of the preceding claims, comprising a step (520) of cleaning a surface (200) of the substrate (100), in particular wherein the step (520) of cleaning is carried out after the step (515) of introducing and / or before the step (525) of coating and / or before the step (535) of breaking. [8] Method (500) according to one of the preceding claims, wherein in the breaking step (535) a tensile force (305) is applied to the surface (200) of the substrate (100), in particular wherein the tensile force (305) is applied to the surface (200) facing the predetermined breaking point (205). [9] Method (500) according to one of the preceding claims, wherein in the step (505) of providing a step (510) of forming a recess (115) and / or the sensitive layer on the surface (200) of the substrate (100) is provided, in particular wherein the step (510) of forming is carried out before the step (515) of introducing. [10] A method (600) for using a microfluidic receiving element according to any one of the preceding claims, wherein the method (600) comprises the following steps: Introducing (605) an aqueous solution into the at least one recess of the receiving element and / or onto the sensitive layer; and Detecting (610) a parameter of a reaction carried out using the introduced aqueous solution in the receiving element. [11] Microfluidic receiving element (110) having a breaking edge (230) through at least one predetermined breaking point (205) on a lateral edge of the microfluidic receiving element (110). [12] Microfluidic device (112) for processing fluids with the microfluidic receiving element (110) according to claim 11. [13] Control device (700; 800) which is configured to execute and / or control the steps (505, 510, 515, 520, 525, 530, 535) of the method (500) according to one of claims 1 to 9 and / or the steps (605, 610) of the method (600) according to claim 10 in corresponding units (705, 710, 715, 720, 725, 730, 735; 805, 810). [14] Computer program configured to execute and / or control the steps (505, 510, 515, 520, 525, 530, 535; 605, 610) of one of the methods (500; 600) according to one of the preceding claims. [15] A machine-readable storage medium on which the computer program according to claim 14 is stored.

Images