Method and apparatus for removing a chip from a wafer film frame, implementation system, and computer program

Abstract

To provide a method and device for removing a chip from an adhesive film using a peeling tool and a gripping tool.SOLUTION: A device 100 for removing a chip is configured such that: the adhesion of a first chip 195 to an adhesive film 192 in an action region is reduced to position the first chip above a peeling tool 110; a negative pressure is applied between the lower surface 192a of the adhesive film and the upper surface 112a of the body of the peeling tool; the adhesion of the first chip to the adhesive film is reduced with the peeling tool, the first chip is gripped with a gripping tool 154 and the first chip is removed; a second chip of a wafer film frame 190 is positioned above the action region; and the adhesion of the second chip to the film is reduced with the peeling tool, the second chip is gripped, and the second chip is removed with the gripping tool. While the wafer film frame is positioned, a negative pressure is temporarily applied between the lower surface of the adhesive film and the upper surface of the body of the peeling tool.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention generally relates to the technical field of mounting (unpackaged) semiconductor chips onto a substrate, which are removed from a wafer film frame or from an artificial wafer. The present invention particularly relates to a removal process in which removal of such chips from a wafer film frame is assisted by a mounting head of at least one ejector pin of an ejector tool. In particular, the present invention relates to a method and an apparatus for removing chips from an adhesive film of a wafer film frame by means of a gripping tool, assisted by an ejector tool. Furthermore, the present invention relates to a mounting system comprising said apparatus and a computer program for implementing said method. [Background technology]

[0002] The mounting of printed circuit boards, also commonly called substrates, or component carriers, is typically carried out by means of an automatic mounting machine, in particular having a mounting head, by which electronic components are picked up at a pick-up position, transported to a mounting area and placed on the component carrier. The components are usually fed by means of a belt on which they are wrapped. After the components have been removed, the belt material must be discarded. This results in a large amount of packaging waste.

[0003] The supply of electronic components formed as semiconductor chips (hereinafter also simply referred to as "chips") can also take place directly from wafers, in order to avoid packaging waste. In this context, a wafer is an assembly which, in addition to the actual wafer, i.e. the slice of semiconductor material, comprises an elastic film and a frame, the film being stretched on the frame and the actual wafer being glued to the film. Such a (glued) film or adhesive film is often called a "wafer film". The wafer glued to the film may already be diced (by a sawing process), as a result of which a number of individual semiconductor chips are glued to the film. Such an assembly consisting of a frame, a film and diced semiconductor chips is also often called a "wafer film frame". Furthermore, in this context, a wafer or a "wafer film frame" may also be a so-called "remounted wafer" or in English a "reconstituted wafer", in which case chips with defects or chips exceeding certain tolerances have been sorted out before being mounted on the film. A wafer film frame with the (selected) semiconductor chips to be mounted is also often called an artificial wafer.

[0004] By stretching the film, the diced chips are somewhat "pulled apart" and picked up by a gripping tool or component holding device, e.g. a so-called vacuum gripper of the mounting head, whereby the picking up of the chips can be assisted by an ejector tool with at least one ejector pin, which pierces or at least bends the adhesive film in such a way that the adhesion of the chip to the adhesive film is reduced.

[0005] The mounting performance of an automatic attachment machine that picks up chips from a wafer film frame is often limited by the process of picking up the chips from each wafer film frame. In this context, the so-called pick-up performance, i.e. the number of chips that can be peeled off from the adhesive film per time unit, is important.

[0006] The process of peeling the chip from the adhesive film of the wafer film frame specifically includes the following steps: (1) positioning a wafer film frame relative to an ejector tool having at least one ejector pin such that the chip is positioned above the ejector tool; (2) applying negative pressure so that the film is sucked over the ejector tool; (3) placing a gripping tool, e.g., an aspirating pipette of a mounting head, directly on top of the chip (from above); (4) moving or extending the ejector pins upward in synchronism with the gripping tool to a certain height above the original height of the film, either piercing the film or simply deforming it, depending on the type of ejector pin used, reducing the area where the tip is attached to the film; (5) waiting for a certain period of time until the chip is completely peeled off from the film; (6) moving or retracting the ejector pin downwardly so that it is located within the housing of the ejector tool while simultaneously removing the peeled chip by a corresponding further movement of the gripping tool or mounting head; (7) releasing the negative pressure; (8) repositioning the wafer film frame relative to the ejector tool so that the next chip to be removed is positioned above the ejector tool; (9) performing steps (1) to (8) again.

[0007] In this process, steps 2 and 7, i.e., applying and releasing the vacuum until the corresponding pressure is reached, take relatively long times, so that removal performance is correspondingly slower or limited. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to improve the ejection performance of an ejector tool. [Means for solving the problem]

[0009] This problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are set forth in the dependent claims.

[0010] According to a first aspect of the present invention, a method for removing chips from an adhesive film of a wafer film frame using a gripping tool with the assistance of a peeling tool is described. The method described includes the steps of (a) positioning a wafer film frame relative to a peeling tool so that a first chip of the wafer film frame is located above an action area of ​​the peeling tool, where the peeling tool interacts with the adhesive film and reduces the adhesion of the first chip to the adhesive film; (b) applying negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool; and (c) (c1) actuating the peeling tool to reduce the adhesion of the first chip to the adhesive film, (c2) gripping the first chip with the gripping tool, and (c3) moving the gripping tool away from the adhesive film with the gripped first chip to remove the first chip. The method according to the present invention further comprises the steps of (d) stopping the peeling tool so that no further interaction occurs between the peeling tool and the adhesive film; (e) repositioning the wafer film frame relative to the peeling tool so that the second chip of the wafer film frame is located above the working area of ​​the peeling tool; and (f) (f1) operating the peeling tool again to reduce the adhesion of the second chip to the adhesive film, (f2) gripping the second chip by the gripping tool or the further gripping tool, and (f3) removing the second chip by moving the gripping tool or the further gripping tool together with the gripped second chip away from the adhesive film. According to the present invention, during the process of repositioning the wafer film frame, negative pressure is further applied at least temporarily between the lower surface of the adhesive film and the upper surface of the peeling tool.

[0011] The described method is based on the realization that it is not necessary to (completely) release the negative pressure between the bottom surface of the adhesive film and the top surface of the peeling tool when repositioning the wafer-film frame, thereby making it possible to avoid or at least reduce waiting times that are necessary or occur in conventional chip removal methods when removing a chip, or more precisely in the time interval between successive removals of two different chips, to (i) completely release the negative pressure (to the respective ambient pressure) before repositioning and (ii) completely build up the negative pressure again after repositioning and before removing the second chip.

[0012] In simple terms, in the method according to the invention, the negative pressure previously applied to (re)position the wafer-film frame is not released, or at least not completely released, until ambient pressure is reached again. As a logical consequence, this negative pressure does not have to be (completely renewed) created before the second chip is removed. This provides a significant time advantage compared to known chip removal processes, with a corresponding improvement in chip removal performance. This allows the chips to be fed to the attachment machine more quickly, improving the actual placement performance of the attachment machine.

[0013] The removal of the second chip can be performed, as described above, by the gripping tool that has already removed the first chip and placed it in the mounting position during that time, or by a further or different gripping tool. In the second case, the first chip can still be held by the (first) gripping tool when the second chip is removed. This means that the gripping tool, the further gripping tool and, if necessary, the further gripping tool are arranged on one and the same multiple mounting head. Then, according to the "Collect And Place" principle, a number of chips corresponding to the number of existing gripping tools are first removed and transported together by the entire mounting head to the mounting area of ​​the automatic mounting machine, where the various chips are placed one after the other, i.e. without further removal of chips, on the substrate or on the film of the artificial wafer in the predetermined mounting position.

[0014] In this specification, the concept of "negative pressure" should be understood as a pressure lower than the current ambient pressure or a pressure lower than the current atmospheric pressure. In a physical sense, negative pressure is a negative pressure difference with the ambient pressure. The negative pressure can be generated by any suitable type of pump known per se and can be adjusted, if necessary, by a suitable valve. Whenever a first negative pressure is described as being greater than another second negative pressure, this means that the first negative pressure has an absolutely smaller pressure value compared to the second negative pressure. In other words, the smaller negative pressure is characterized by a pressure value closer to the ambient pressure than the pressure value of the larger negative pressure.

[0015] In accordance with the present invention, negative pressure is maintained at least temporarily during the process of repositioning the wafer-film frame, in other words, the entire repositioning is not performed under negative pressure but rather at atmospheric pressure.

[0016] It is only important that the described sub-steps are performed in a coordinated manner when removing the first chip and / or when removing the second chip, and the specific order of these sub-steps is not important. In particular, gripping of the chip can take place before, after or during the actuation of the peeling tool. All that matters is that, before moving the gripping tool or the further gripping tool away from the adhesive film, the (re)actuation of the peeling tool ensures that the adhesion of the chip to the (upper surface of) the adhesive film is reduced to such an extent that the gripping tool can reliably grip and hold the chip with the gripping force available at the time.

[0017] The described peeling tool preferably comprises a body or at least one component having a flat upper surface, against which the (non-adhesive) lower surface of the adhesive film can abut (assisted by negative pressure).

[0018] In this specification, a wafer is to be understood in particular as a so-called wafer film frame, which on its adhesive film, depending on the application case, has either (i) semiconductor chips diced by a sawing process or (ii) semiconductor chips pre-mounted on the adhesive film. The wafer or wafer film frame further comprises a frame on which the elastic film is stretched, as mentioned at the beginning. The frame of the wafer film frame may be a flat metal frame, in particular to avoid unnecessary expansion in height, and may also serve to allow easy and safe handling of the wafer film frame. Furthermore, the frame may be a so-called grip ring, which in principle can be manufactured from any material, such as steel and / or plastic. Furthermore, the film may be stretched on the metal frame or grip ring, so that the individual chips are somewhat spaced apart from each other.

[0019] Handling of the wafer film frame can be performed, for example, using a robot or a clearly simpler handling device which engages the frame with a suitable gripper and, by appropriately moving the gripper, moves the wafer or wafer film frame, for example, only along a predetermined two- or three-dimensional trajectory.

[0020] The techniques described herein are primarily concerned with the removal of chips from wafer film frames, and not with the processing of semiconductor wafers (slices of semiconductor material) themselves, and therefore the term "wafer" is often used in this specification as a shortened term to "wafer film frame."

[0021] In the present specification, a chip is to be understood as an electronic component that can be removed from a wafer and that can be mounted. In particular, a chip is an unpackaged or "bare" electronic component that is mainly composed of semiconductor material and that has been processed or manufactured together with other chips on the same semiconductor wafer. Apart from the semiconductor material of the original semiconductor wafer, the chip can also have metallic terminal contacts that are formed simultaneously for all chips of the semiconductor wafer within the scope of a suitable post-processing. In the case of spherical terminal contacts, the chip can be a so-called Flip Chip Ball Grid Array (FCBGA), which is not particularly packaged. Furthermore, the chip can also have convex terminal contacts that are applied by electric current, which also contain a suitable electrically and thermally conductive joining material (solder). In general, such components are called Chip Scale Packages (CSPs). After mounting the unpackaged chip on a component carrier, for example a printed circuit board (PCB) or on an elastic film of an artificial wafer, the mounted chip can be protected from harmful environmental influences, if necessary, with a suitable coating and / or potting compound. The potting compound in this context can be an underfill material that is inserted under the mounted chip.

[0022] According to one embodiment of the invention, the peeling tool has at least one mechanical peeling element which, upon actuation of the peeling tool, presses against the adhesive film from below and thereby locally lifts it off.

[0023] The described mechanical lifting of the adhesive film has the advantage that a rapid and effective decrease in adhesion can occur when the peeling element is correspondingly actuated, whereby the decrease in adhesion can occur in particular as a result of a decrease in the actual adhesion area between the tip and the adhesive film due to a changed three-dimensional shape or curvature of the adhesive film, which can occur simply because during the described actuation of the (at least one) peeling element, the peeling element is lifted from the body of the peeling tool and presses the adhesive film from below.

[0024] That is, the actuation of the peeling tool can be performed by moving at least one mechanical peeling element upwards from the body of the peeling tool as described above. In this case, the adhesive film is locally lifted upwards and thus locally spaced from the upper surface of the peeling tool or from the upper surface of the body. Correspondingly, the stopping of the peeling tool includes at least one mechanical peeling element being at least partially retracted downwards into the body of the peeling tool. In this case, the mechanical peeling element is preferably retracted downwards to such an extent that it no longer abuts against the lower surface of the adhesive film, which is now not to be lifted again. This makes it possible to prevent damage to the adhesive film and / or the peeling element when repositioning the wafer film frame.

[0025] According to a further embodiment of the invention, the mechanical stripping element is an ejector pin.

[0026] Typically, the pins have a very small end face, which presses against the adhesive film from below during the operation of the peeling tool, so that the adhesion area of ​​the adhesive between the film and the chip can be reduced particularly significantly. As mentioned above, the tip of the ejector pin can either lift or pierce the adhesive film, depending on the specific configuration of the method. In the latter case, the adhesion area between the adhesive film and the chip is reduced to zero.

[0027] According to a further embodiment of the invention, the mechanical peeling element is an ejector plate with an elongated upper surface. This means that when the mechanical peeling element is actuated or lifted, the film in the area of ​​the chip to be removed rests against an elongated and relatively narrow edge or web. This allows to reduce local distortion of the film, especially outside the area of ​​the original adhesive surface of the chip. Thus, adjacent chips of the wafer-film frame that have not yet been removed are not affected or are only slightly affected by the removal of the chip. In particular, their adhesive strength is not (prematurely) impaired by the removal of the chip and the associated undesired bending of the adhesive film outside the area of ​​the just removed chip.

[0028] The stripping tool may preferably be a plurality of ejector plates arranged parallel to one another, each having an elongated upper surface, and individually actuatable or liftable, such that by sequentially activating or lifting different ejector plates, the adhesion of the chip can be sequentially reduced in different adhesion part areas, thus obtaining an effective reduction of adhesion over the entire adhesion area of ​​the chip.

[0029] According to another embodiment of the invention, the stripping tool comprises an energy source that transfers energy to the adhesive film within an area of ​​action, thereby reducing the adhesive strength of the adhesive film.

[0030] In this case, the energy can be transferred to the adhesive film in a contactless manner in the form of electromagnetic radiation. The radiation can include visible or non-visible light, for example light in the infrared spectral range. For example, the energy source can include at least one laser or light-emitting diode (LED). The energy source can further include a radiation-transparent contact window against which the adhesive film abuts by applying negative pressure. The negative pressure can be applied to the adhesive film from below through an opening in the contact window or an opening next to the contact window.

[0031] The energy can be thermal energy, which is transferred locally without contact, in the form of radiation, i.e. electromagnetic radiation with very long wavelengths. Alternatively, or in combination, thermal energy can also be transferred by contact through thermal conduction. In the latter case, the energy source can have a heated or heatable surface that is brought into contact with the adhesive film. In this case, too, it is possible to apply negative pressure to the underside of the adhesive film using openings on the heated or heatable surface or next to the heated or heatable surface. The heated or heatable surface can, for example, have silicon carbide. This is a material that advantageously allows heating with rapid temperature gradients in time.

[0032] According to a further embodiment of the invention, a negative pressure is applied between the lower surface of the adhesive film and the upper surface of the peeling tool during the entire repositioning process. In simple terms, this means that the negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool is not released, or at least not released completely, at least in the time frame between the removal of the first chip and the removal of the second chip. This has the advantage that a shorter time is needed to build up the necessary negative pressure before the removal of the second chip in order to obtain the necessary negative pressure for the reliable removal of the second chip.

[0033] According to a further embodiment of the invention, the negative pressure applied between the underside of the adhesive film and the upper surface of the peeling tool during the entire repositioning process is less than the negative pressure applied between the underside of the adhesive film and the upper surface of the peeling tool during the removal of the first chip and / or the removal of the second chip, which has the advantage that the repositioning is not or only only slightly hindered by the pneumatic adhesion of the adhesive film to the upper surface of the body, which is detrimental during positioning.

[0034] In this connection, it is clear that the greater the negative pressure during positioning, the more the described "pneumatic adhesion" can interfere with the positioning of the wafer film frame. The optimum compromise between (i) the highest possible negative pressure during positioning in order to reduce the time interval between negative pressure changes, and (ii) the lowest possible negative pressure during positioning in order to allow the wafer film frame to move as freely as possible relative to the peeling tool, can be easily determined by experiment for the particular application, i.e. by observing at what point in time a sufficiently good relative mobility is obtained when gradually decreasing the negative pressure.

[0035] According to a further embodiment of the invention, the difference between (i) the negative pressure during removal of the first and / or second tip and (ii) the negative pressure during repositioning is at least partially due to leakage. This has the advantage that no complex pressure control mechanisms need to be used to achieve the reduction in negative pressure during positioning. In particular, the reduction in negative pressure for repositioning is obtained by simply stopping the pump and / or (temporarily) pneumatically decoupling the pump from the peeling tool and / or the adhesive film by means of a shut-off valve.

[0036] The expression "leak" in this context particularly refers to an air flow caused by the inflow of air from the surroundings into a spatial region of negative pressure, whereby the larger the opening or cross section of the corresponding leak is, the faster the negative pressure after removal of the first and / or second tip drops to the negative pressure required for problem-free repositioning.

[0037] According to a further embodiment of the invention, the course of the negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool over time is (actively) controlled, which can be done, for example, by corresponding control of a pump which creates the negative pressure and / or by suitable pneumatic control valves between such pump and the peeling tool or the adhesive film.

[0038] By means of the described active control it is possible to keep the entire process under pneumatic control in an advantageous manner, especially when the negative pressure varies (largely) during the various steps of the described method, As a result, high process reliability can be guaranteed despite high removal performances.

[0039] According to a further embodiment of the invention, the time course of the negative pressure is controlled by means of a pressure sensor. By means of the described control (in a closed control loop), the time course of the negative pressure can be adapted with high precision to a predefined target pressure course. This results in a further improved compromise between high removal performance and high process reliability.

[0040] According to a further embodiment of the invention, the course of the negative pressure over time is actively controlled by means of an analog air valve, which can preferably be arranged between the pump generating the negative pressure and the peeling tool or the adhesive film.

[0041] The described analog air valve can be any pneumatic device capable of inducing a pressure change by the intervention of an open-loop or closed-loop control. The analog air valve can in particular be a valve with two inlets and one outlet, one inlet of which is pneumatically connected or connected to a pump and the other inlet to the surrounding environment. The outlet can in particular be pneumatically connected to a spatial region of negative pressure between the peeling tool and the adhesive film. The analog pressure change can be effected through the ratio of the flow cross section or flow resistance between the two inlets.

[0042] According to a further embodiment of the present invention, the method further comprises the steps of (f) stopping the peeling tool again after removing the second chip, so that no further interaction occurs between the peeling tool and the adhesive film; (g) repositioning the wafer film frame relative to the peeling tool (along at least one horizontal direction) so that the third chip of the wafer film frame is located above (preferably directly) the working area of ​​the peeling tool; (h) (h1) operating the peeling tool again to reduce the adhesion of the third chip to the adhesive film; (h2) gripping the third chip by the gripping tool or the further gripping tool; (h3) removing the third chip by moving the gripping tool or the further gripping tool together with the gripped third chip away from the adhesive film. During the process of repositioning the wafer film frame, negative pressure is applied at least temporarily between the lower surface of the adhesive film and the upper surface of the peeling tool.

[0043] That is, the described method can rapidly remove more than one chip, i.e., with high removal performance. The method can be repeated until a desired number of chips is removed from the wafer film frame. The desired number of chips can be the total number of chips remaining on the wafer film frame, or a specific number of chips that need to be removed for a specific mounting operation.

[0044] According to a further aspect of the present invention, an apparatus for removing chips from the adhesive film of a wafer film frame is described, particularly by carrying out the above-mentioned type of method.The apparatus described includes: (a) a peeling tool configured to reduce the adhesion of chips to the adhesive film in the working area; (b) a positioning device for successively positioning the wafer film frame relative to the peeling tool, so that a plurality of chips of the wafer film frame are successively located above the working area; (c) a negative pressure generating device configured to apply negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool; and (d) a mounting head having at least one gripping tool configured to (d1) operate the peeling tool so that the adhesion of chips to the adhesive film is reduced, (d2) grip the chip by the gripping tool, and (d3) move the gripping tool away from the adhesive film together with the gripped chip to remove one chip, respectively. The negative pressure generating device is configured to continue to apply negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool at least temporarily while positioning the wafer film frame after removing the first chip and before removing the second chip, each of which is performed with negative pressure applied between the lower surface of the adhesive film and the upper surface of the peeling tool.

[0045] The described chip removal device is also based on the realization that it is not necessary to (completely) release the negative pressure between the bottom surface of the adhesive film and the top surface of the peeling tool in order to position the wafer film frame, which makes it possible to avoid or at least shorten the waiting times that are necessary in conventional chip removal devices in the time interval between successive removal of two different chips, in order to (i) completely release the negative pressure (to the respective ambient pressure) before positioning the wafer film frame and (ii) completely build up the negative pressure again after positioning and before removing the further chip.

[0046] According to one embodiment of the present invention, the negative pressure forming device comprises a pump, a controllable valve and a control unit, by means of which the pump and / or the controllable valve can be controlled so as to vary the negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool.

[0047] Due to the control caused by the control unit, it is advantageously possible to keep the entire process of successive pick-up of multiple chips under (active) control, even if the negative pressure can (largely) vary, as a result of which high process reliability can be guaranteed despite high pick-up performance.

[0048] According to a further embodiment of the present invention, the device further comprises a pressure sensor, which is communicatively coupled to the control unit, and the control unit is configured in an information technical manner to control the pump and / or the controllable valve based on the pressure measurements of the pressure sensor so as to produce a predetermined progression of the negative pressure over time.

[0049] The pressure sensor can be a component of a closed control loop, which makes it possible to adapt the time course of the negative pressure to a predefined target pressure course with particularly high precision, which allows for an even better compromise between high removal performance and high process reliability.

[0050] According to a further aspect of the present invention, a mounting system for mounting a chip on a substrate is described. The mounting system described comprises (a) the above-mentioned device for picking up the chip, (b) a first pick-up device for picking up the wafer film frame, and (c) a second pick-up device for picking up the substrate to be mounted. A mounting head with at least one gripping tool is configured to pick up the chip from the wafer film frame and place it on the substrate.

[0051] The described mounting system is based on the recognition that the above-mentioned chip removal device, which is a component of the mounting system, is capable of providing high removal performance, so that the mounting performance, i.e., the number of chips that can be placed on a substrate from a wafer film frame within a given time unit, is no longer (so largely) determined or limited by air pressure relaxation that may occur within the chip removal device.

[0052] The first pick-up device is preferably mechanically connected to the positioning device, so that the first pick-up device is also moved together with the wafer film frame during positioning of the picked-up wafer film frame.

[0053] The placement of the chips can be done not only directly from the wafer film frame onto the substrate, but also indirectly by using at least one additional chip handling device which performs the final placement of the chips onto the substrate, in this regard the chip handling device can include, for example, further mounting heads and / or temporary storage locations for the chips.

[0054] According to a further aspect of the invention, a computer program for operating an apparatus for removing chips from an adhesive film on a wafer film frame is described, in particular an apparatus of the type described above, which computer program, when executed by a data processing unit, is configured to perform the above-mentioned method for removing chips from an adhesive film on a wafer film frame.

[0055] In this specification, such a computer program is synonymous with the notion of a program element, computer program product and / or computer readable medium comprising instructions for controlling a computer system to appropriately adjust the functionality of the system or method to achieve the effects related to the method according to the invention.

[0056] The computer program may be implemented as a computer readable instruction code in any suitable programming language, for example JAVA, C++, etc. The computer program may be stored on a computer readable storage medium (CD-ROM, DVD, Blu-ray disk, removable drive, volatile or non-volatile memory, internal memory / processor, etc.). The instruction code is capable of programming a computer or other programmable device, in particular a control computer of an automatic attachment machine, to perform a desired function. Furthermore, the computer program may be provided over a network, such as the Internet, and may be downloaded by a user from the network as required.

[0057] The invention can be implemented by means of a computer program, ie, software, by means of one or more special electronic circuits, ie, hardware, or in any hybrid form, ie, using software and hardware components.

[0058] The invention described herein may also be implemented using a "cloud" network having corresponding virtual storage space and corresponding virtual computing power.

[0059] It is noted that embodiments of the present invention have been described with respect to different subject matters of the invention. In particular, some embodiments of the present invention have been described with apparatus claims and other embodiments of the present invention have been described with method claims. However, it will be immediately apparent to a person skilled in the art upon reading this specification that, unless expressly stated otherwise, any combination of features belonging to different subject matters of the invention is possible in addition to combinations of features belonging to one subject matter of the invention.

[0060] Further advantages and features of the present invention will become apparent from the following illustrative description of the presently preferred embodiments. [Brief description of the drawings]

[0061] [Figure 1] FIG. 2 illustrates an apparatus for ejecting chips from an adhesive film of a wafer film frame assisted by an ejector tool having multiple ejector pins according to one embodiment of the present invention. [Diagram 2] A diagram illustrating the interaction between (i) the movement of a gripping tool, (ii) the movement of (at least) one ejector pin, and (iii) the negative pressure applied between the adhesive film and the ejector tool in relation to the removal of a chip from an adhesive film on a wafer film frame. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] The embodiments described below are only a limited selection of possible embodiment variations of the present invention, and in particular since the features of the individual embodiments can be appropriately combined, many different embodiments are considered to be clearly disclosed to those skilled in the art as variations of the embodiments explicitly shown in this specification.

[0063] In addition, it is noted that spatial concepts, such as "front" and "back", "up" and "down", "left" and "right", etc., are used to describe the relationship of one element to another element as shown in the figures. Thus, the spatial concepts may be applied in orientations other than those shown in the figures. However, it is self-evident that all such spatial concepts are relative to the orientation shown in the figures for ease of explanation and are not necessarily limiting, since each illustrated device, when used, may assume an orientation other than that shown in the figures.

[0064] Fig. 1 shows an apparatus 100 for ejecting chips 195 from an adhesive film 192 of a wafer film frame 190 with the aid of an ejector tool 110 according to an embodiment of the invention. The basic principle of ejecting chips 195 with the aid of an ejector tool 110 is known per se and will not be described here from scratch. In particular, as mentioned above, it is known to use an ejector plate instead of the ejector pins 114 shown in Fig. 1. Non-mechanical reduction of adhesive forces by means of radiation and / or heat is also known per se to a person skilled in the art and will not be mentioned again in detail.

[0065] The wafer film frame 190 has, as is known, a frame structure 194 on which an adhesive film 192 is applied. The chips 195 are located on the adhesive surface of the film 192. To eject the chips 195, the wafer film frame 190 is displaced at least along the x-direction and / or the y-direction by means of a positioning device 130, shown only very diagrammatically, which directly or indirectly grips the wafer film frame 190 at its frame structure 194, so that the chips 195 to be ejected are located directly above the ejector tool 110. More precisely, the chips 195 to be ejected are located directly above the ejector pins 114 of the ejector tool 110.

[0066] The apparatus 100 further comprises a mounting head 150, which is movable above the wafer film frame 190 by means of a positioning system, not shown. The mounting head 150, which may be a placement head known per se, comprises at least one gripping tool 154 configured in the form of a suction pipette, which is movable along a z-direction (perpendicular to the x- and y-directions shown in FIG. 1) perpendicular to the mounting head chassis 152 by means of a linear drive, not shown. At the start of the chip pick-up process, the gripping tool 154 is positioned so that its front face, which is a lower end face having a suction port, not shown in FIG. 1, directly abuts against the upper surface of the chip 195.

[0067] The removal of the tip 195 is accomplished in a known manner by (a) moving the ejector pin 114 upward relative to the body 112 of the ejector tool 110, and (b) simultaneously and to the same extent, moving the gripping tool 154 upward. If the adhesive film 192 is pierced or bent, the adhesion of the tip 195 to the film 192 will be lost or reduced. The suction vacuum created through the suction tube of the gripping tool 154 is not to be confused with the vacuum between the film 192 and the ejector tool 112 described below, which also functions in a known manner to transfer the tip 195 from the film 192 to the gripping tool 154. The negative pressure between the adhesive film 192 and the ejector tool 110, more precisely between the film 192 and the upper surface 112a of the body 112 of the ejector tool 110, acts in a known manner according to the embodiment shown in the figure, such that the ejector pins 114 penetrate the film 192 and the surface is not merely lifted. Alternatively, if sufficient negative pressure is present at the lower surface 192a of the film 192, the ejector pins 114 may act in such a way that the film 192 is only locally lifted directly at the tips of the ejector pins 114, significantly reducing the adhesive area and therefore the adhesive force between the adhesive upper surface of the film 192 and said tips 195. The described negative pressure is created by a negative pressure creating device 140 and is applied to the lower surface 192a of the adhesive film 192 through openings provided on or in the upper surface 112a of the body 112, not shown.

[0068] 1, the negative pressure forming device 140 includes a pump 142 pneumatically connected through an unnumbered air conduit to a first air inlet 144a of a controllable valve 144. A second air inlet 144b of the controllable valve 144b is pneumatically connected to the ambient environment. An air outlet 144c of the controllable valve 144 is pneumatically connected to an air inlet 110a of the interior space of the body 112.

[0069] According to the embodiment shown in the figure, the controllable valve 144 is a so-called analog valve, which is controlled by the control unit 146 through a control line shown in dashed lines and not numbered. According to the embodiment shown in the figure, depending on the control by the control unit 146, the ratio between (a) the effective flow cross section of the first air inlet 144a and (b) the effective flow cross section of the second air inlet 144b is adjusted. The higher this ratio is, the smaller the flow of intake air 145 that enters the controllable valve 144 through the second air inlet 144b and has to be sucked out by the pump 142. A corresponding proportion of the suction force of the pump 142 does not contribute to the creation or increase of a negative pressure on the lower surface 192a of the film 192. According to the technique described herein, it is possible to arbitrarily adjust the negative pressure applied to the lower surface 192a of the film 192 by the control unit 146 as a function of time.

[0070] According to the embodiment shown in the figure, a larger negative pressure is set during the actual removal of the chip 195 than during the time window in which the wafer film frame 190 is newly positioned or moved in the xy plane relative to the ejector tool 110. Thus, it is no longer necessary to (a) completely re-create the desired negative pressure after positioning the wafer film frame 190 and before removal of said chip 195, and / or (b) completely create the negative pressure after removal of the chip 195 and before positioning the wafer film frame 190 ("towards the next chip 195 to be removed"). This shortens the time window in which the described pressure changes occur, with a corresponding improvement in removal performance.

[0071] According to the embodiment shown in the figure, the device 100 further comprises a pressure sensor 120 arranged inside the body 112. The pressure sensor 120 measures the current negative pressure at all times and transfers the corresponding pressure measurement to the control unit 146 through a communication line shown in dashed lines (not numbered). The control unit 146, through the intervention of a corresponding closed-loop control for such control of the analog controllable valve 144, functions in such a way that at any moment of the method described herein for removing a plurality of chips 195, a desired negative pressure is always applied between the lower surface 192a of the adhesive film 192 and the upper surface 112a of the body 112.

[0072] An operator can configure and / or monitor the entire removal process through the display and operating terminal 160 .

[0073] 2 illustrates the interaction between (i) the movement of the gripping tool 154, (ii) the movement of the two ejector pins 114, and (iii) the negative pressure dp applied between the adhesive film 192 and the ejector tool 110 with respect to the removal of a chip 195 from the adhesive film 192 of the wafer film frame. FIG 2 illustrates only the time frame during which the wafer film frame is not moving relative to the ejector tool 110 and the chip to be removed is in a position beneath the gripping tool 154.

[0074] The vertical movement of the gripping tool 154 as a function of time t is visualized by a dashed line with the reference M1. The progression of the movement of the two ejector pins 114 of FIG. 2, which also move exclusively vertically, is shown below on the same time axis t and is marked with the reference M2. The bottom graph of FIG. 2 also shows, on the same time scale, the progression of the vacuum applied between the adhesive film 192 and the ejector tool 110, which progression is marked with the reference P1. As is clear from FIG. 2, in the example embodiment described therein, the vacuum is never zero but varies between two boundary values ​​-300 mbar and -750 mbar. Obviously, other vacuum boundary values ​​and / or other vacuum progressions can also be selected depending on the application. For the present invention, it is only necessary that the movements not shown in FIG. 2 are not entirely performed without the application of vacuum.

[0075] In the illustrated embodiment, removal of the chip 195 begins at time t0 with application of a relatively high vacuum between the adhesive film 192 and the ejector tool 110, where the vacuum is increased from -300 mbar to -750 mbar in the time frame from t0 to time t1, and then maintained for a relatively long time interval (until time t12, after removal of the chip 195).

[0076] As is clear from Fig. 2, in the embodiment shown in this figure, at time t1, the gripping tool 154 starts to move downward. At this time, the speed of the downward movement determines the gradient of the corresponding first section of the curve M1. At the same time, the ejector pin 114 starts to move upward. At time t2, the tip of the ejector pin 114 abuts against the lower surface of the adhesive film 192.

[0077] At time t3 (long after the maximum negative pressure of -750 mbar has been reached), the gripping tool 154 is moved at a reduced descent speed towards the tip 195. Reducing the descent speed to avoid the gripping tool 154 hitting the tip 195 hard is known to those skilled in the art and therefore will not be discussed in detail herein.

[0078] At time t4, the end face of the gripping tool 154 configured as an aspirating pipette comes into contact with the upper surface of the tip 195, and the vertical downward movement of the aspirating pipette 154 stops. At the same time, in the aspirating tube of the aspirating pipette 154, a vacuum is created in a known manner between the aspirating pipette 154 and the tip 195. The start of the creation of the vacuum at time t4 is indicated by arrow 272 in Fig. 2. At time t5, highlighted by arrow 274, the tip 195 has (later) reached or will reach the maximum vacuum that it can sustain.

[0079] At time t6, the movement of the tip 195 from the adhesive film 192 to the aspirating pipette 154 begins with both ejector pins 114 moving further upwards, in the embodiment shown here piercing the adhesive film 192 and pressing the tip 195 against the front end face of the aspirating pipette 154. Shortly thereafter, at time t7, a corresponding upward movement of the aspirating pipette 154 begins. Thereafter, the ejector pins 114 and the aspirating pipette 154 move upwards in the same way, until time t8.

[0080] After a certain time delay caused by the adhesive bond between the adhesive film 192 and the tip 195 not being released immediately, the transfer of the tip 195 from the adhesive film 192 to the suction pipette 154 is completed at time t9, which is particularly highlighted by arrow 276 in FIG. 2.

[0081] At time t10, the aspirating pipette 154 is lifted upward with the gripped tip 195, first slowly, then more rapidly from time t11 onwards, completing the removal of the tip 195 "from the perspective of the wafer film frame".

[0082] At time t12, both ejector pins 114 are retracted downwards again into the body 112 of the ejector tool 110. At the same time, the vacuum between the ejector tool 110 and the adhesive film 192 is released. At time t13, a final vacuum of -300 mbar is reached. The ejector pins 114 reach their starting position at time t14.

[0083] After time t14, the wafer film frame can be moved horizontally relative to the ejector tool 110 so that the next chip 195 is located above the ejector tool 110. The above procedure can then be performed again to retrieve the next chip 195.

[0084] It should be noted that the word "comprises" does not exclude other elements, and "a" does not exclude a plurality. It is also possible to combine elements described in association with different embodiments. It should also be noted that reference signs in the claims shall not be interpreted as limiting the scope of protection of the claims. [Explanation of symbols]

[0085] 100 Device for removing chips 110 Peeling tool / ejector tool 110a Air inlet 112 Main unit 112a Top side 114 Mechanical peeling element / ejector pin 120 Pressure Sensor 130 Positioning device 140 Negative pressure forming device 142 Pump 144 Controllable Valves 144a first air inlet 144b Second air inlet 144c Air outlet 145 Intake air 146 Control Unit 150 Mounting Head 152 Chassis 154 Grasping tool / Aspiration pipette 160 Display and operation terminals 190 Wafer Film Frame 192 Adhesive Film 192a Bottom side 194 Frame Structure 195 Chips 272 Start applying negative suction pressure 274 Attainment of negative suction pressure 276 End of tip transfer from adhesive film to aspirator pipette dp negative pressure t time M1 Tool movement transition M2 Ejector pin movement transition P1 Negative pressure over time t# time point (#=0, 1, 2, ..., 14)

Claims

1. A method for removing a chip (195) from an adhesive film (192) of a wafer film frame (190) using a gripping tool (154) assisted by a peeling tool (110), the method comprising: positioning the wafer film frame (190) relative to the peeling tool (110) such that a first chip (195) of the wafer film frame (190) is located above an area of ​​action of the peeling tool (110), where the peeling tool (110) interacts with the adhesive film (192) to reduce adhesion of the first chip (195) to the adhesive film (192); applying a negative pressure between a lower surface (192a) of the adhesive film (192) and an upper surface (112a) of the peeling tool (110); (i) actuating the peeling tool (110) to reduce adhesion of the first tip (195) to the adhesive film (192); (ii) gripping the first tip (195) with the gripping tool (154); and (iii) removing the first tip (195) by moving the gripping tool (154) with the gripped first tip (195) away from the adhesive film (192); stopping the peel tool (110) so that no further interaction occurs between the peel tool (110) and the adhesive film (192); repositioning the wafer film frame (190) relative to the peeling tool (110) such that a second chip (195) of the wafer film frame (190) is positioned above an area of ​​action of the peeling tool; and (i) actuating the peeling tool (110) again to reduce adhesion of the second chip (195) to the adhesive film (192), (ii) gripping the second chip (195) by the gripping tool (154) or a further gripping tool, and (iii) removing the second chip (195) by moving the gripping tool (154) or the further gripping tool together with the gripped second chip (195) away from the adhesive film (192), The method further comprising at least temporarily applying a negative pressure between a lower surface (192a) of the adhesive film (192) and an upper surface (112a) of the peel tool (110) during the process of repositioning the wafer film frame (190).

2. 2. The method according to claim 1, wherein the peeling tool (110) has at least one mechanical peeling element (114) which, upon actuation of the peeling tool (110), presses against the adhesive film (192) from below, thereby locally lifting the adhesive film (192).

3. The method of claim 2 , wherein the mechanical stripping element is an ejector pin (114).

4. The method of claim 2 , wherein the mechanical stripping element is an ejector plate having an elongated upper surface.

5. 3. The method of claim 2, wherein the peeling tool includes an energy source that transfers energy to the adhesive film (192) within an area of ​​action, thereby reducing the adhesive strength of the adhesive film (192).

6. The method of claim 1 , wherein negative pressure is applied between a lower surface (292a) of the adhesive film (292) and an upper surface (112a) of the peel tool (110) throughout the repositioning process.

7. 2. The method of claim 1, wherein a negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) throughout the repositioning process is less than a negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) during removal of the first tip (195) and / or removal of the second tip (195).

8. 8. The method of claim 7, wherein a difference between (i) the negative pressure when removing the first tip (195) and / or the second tip (195) and (ii) the negative pressure when repositioning is due, at least in part, to a leak.

9. The method of claim 1 , wherein a progression of a negative pressure applied between a lower surface (192a) of the adhesive film (192) and an upper surface (112a) of the peeling tool (110) over time is controlled.

10. 10. The method of claim 9, wherein the course of the negative pressure over time is closed-loop controlled by means of a pressure sensor (120).

11. 10. The method of claim 9, wherein the negative pressure over time is actively controlled using an analog air valve (114).

12. Furthermore, after removing the second chip (195), stopping the peeling tool (110) again so that no further interaction occurs between the peeling tool (110) and the adhesive film (192); repositioning the wafer film frame (190) relative to the peeling tool (110) such that a third chip (195) of the wafer film frame (190) is located above an area of ​​action of the peeling tool (110); (i) actuating the peeling tool (110) again to reduce adhesion of the third tip (195) to the adhesive film (192); (ii) gripping the third tip (195) with the gripping tool (154) or a further gripping tool; and (iii) removing the third tip (195) by moving the gripping tool (154) or the further gripping tool together with the gripped third tip (195) away from the adhesive film (192), 2. The method of claim 1, wherein negative pressure is applied between a lower surface (292a) of the adhesive film (192) and an upper surface (112a) of the peel tool (110) at least temporarily during the process of repositioning the wafer film frame (190).

13. An apparatus (100) for carrying out the method according to claim 1 in particular for removing a chip (195) from an adhesive film (192) of a wafer-film frame (190), said apparatus comprising: a peeling tool (110) configured to reduce adhesion of the chip (195) to the adhesive film (192) at an action area; a positioning device (130) for successively positioning the wafer film frame (190) relative to the peeling tool (110) such that a plurality of chips (195) of the wafer film frame (190) are successively positioned above the working area; a negative pressure forming device (140) configured to apply a negative pressure between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110); and a mounting head (150) having at least one gripping tool (154) configured to: (i) actuate the peeling tool (110) so that adhesion of the chips (195) to the adhesive film (192) decreases; (ii) grip the chips (195) with the gripping tool (154); and (iii) remove one chip (195) each by moving the gripping tool (154) together with the gripped chips (195) away from the adhesive film (192); The negative pressure forming device (140) is configured to continue to apply negative pressure between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) at least temporarily while positioning the wafer film frame (190) after removing a first chip (195) and before removing a second chip (195), each of which is removed with negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110).

14. The apparatus (100) of claim 13, wherein the negative pressure forming device (140) comprises a pump (142), a controllable valve (144) and a control unit (146), by means of which the pump (142) and / or the controllable valve (144) can be controlled so as to vary the negative pressure between the lower surface (192a) of the adhesive film (190) and the upper surface (112a) of the peeling tool (110).

15. 15. The device (100) of claim 14, further comprising a pressure sensor (120) communicatively coupled to the control unit (146), the control unit (146) being configured in an information technical manner to control the pump (142) and / or the controllable valve (144) based on pressure measurements of the pressure sensor (120) so as to produce a predetermined progression of negative pressure over time.

16. A mounting system for mounting a chip (195) on a substrate, comprising: A device (100) for extracting chips (195) according to claim 13; a first pick-up device for picking up a wafer film frame (190); and a second pick-up device for picking up the substrate to be mounted; A mounting system, wherein a mounting head (150) has at least one gripping tool (154) and is configured to pick the chip (195) from the wafer film frame (190) and place it on the substrate.

17. A computer program for operating an apparatus (100) for removing a chip (195) from an adhesive film (192) of a wafer film frame (190), in particular the apparatus (100) according to claim 13, the computer program being configured to perform the method according to claim 1 when the computer program is executed by a data processing unit (146).

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