JP2024019098A - Method and device for removing chip from wafer film frame, mounting system, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: 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

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention generally relates to the technical field of mounting (unpackaged) semiconductor chips from a wafer film frame or from a synthetic wafer onto a substrate. The invention particularly relates to an ejection process in which the ejection of such chips from a wafer film frame is assisted by a mounting head of each at least one ejector pin of an ejector tool. In particular, the present invention relates to a method and apparatus for ejecting chips from an adhesive film of a wafer film frame using a gripping tool with the aid of an ejector tool. Furthermore, the invention relates to an implementation system having the device and a computer program for implementing the method.

The mounting of printed circuit boards or component carriers, also commonly referred to as substrates, is typically carried out using an automatic mounting machine, which in particular has a mounting head, by which the electronic components are picked up at a pick-up position and transported to the mounting area. and placed on the component carrier. Parts are typically supplied using belts in which the parts are packaged. After the parts are removed, the belt material must be discarded. This results in a large amount of packaging waste.

The supply of electronic components formed as semiconductor chips (hereinafter also simply referred to as "chips") can also be carried out directly from wafers, in order to avoid packaging waste. In this context, a wafer is an assembly comprising, in addition to the actual wafer, ie a slice of semiconductor material, an elastic film and a frame, the film being stretched to the frame and the actual wafer being glued to the film. Such (adhesive) or adhesive films are often referred to as "wafer films". The wafer adhered to the film may already have been diced (by a sawing process), resulting in a large number of individual semiconductor chips being adhered to the film. Such an assembly of frame, film, and diced semiconductor chips is often referred to as a "wafer film frame." Furthermore, in this connection, a wafer or a "wafer film frame" may also be a so-called "reconstituted wafer" or in English a "reconstituted wafer", in which case the wafer is , chips with defects or chips exceeding a certain tolerance are sorted out. A wafer film frame with (selected) semiconductor chips to be mounted is often also called an artificial wafer.

By stretching the film, the diced chips are "pulled apart" somewhat and are picked up by a gripping tool or component holding device, for example a so-called vacuum gripper of the mounting head. In this case, the pick-up of the chip can be assisted by an ejector tool having at least one ejector pin, with which the adhesive film is pierced or pierced in such a way that the adhesion of the chip to the adhesive film is reduced. Or at least curved.

The mounting performance of automatic mounting machines that pick up chips from wafer film frames is often limited by the process of picking up chips from each wafer film frame. In this connection, the so-called removal performance, ie the number of chips per unit of time that can be peeled off from the adhesive film, is important.

The process of peeling the chips from the adhesive film of the wafer film frame includes, inter alia, 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 located above the ejector tool;
(2) applying negative pressure so that the film is suctioned above the ejector tool;
(3) placing a gripping tool, for example a suction pipette of a mounting head, directly on the top surface of the chip (from above);
(4) moving or extending the ejector pin upward to a certain height above the original height of the film in synchronization with the gripping tool, depending on the type of ejector pin used; piercing or simply deforming to reduce the area where the chip adheres 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 downwards so that it is located within the housing of the ejector tool while simultaneously ejecting the stripped chip by a corresponding further movement of the gripping tool or the mounting head; ,
(7) Step of releasing negative pressure;
(8) repositioning the wafer film frame relative to the ejector tool so that the next chip to be removed is located above the ejector tool;
(9) A step of re-executing steps (1) to (8).

Since the process requires a relatively long time for steps 2 and 7, i.e. applying and releasing negative pressure until the corresponding pressure is reached, the removal performance is correspondingly low or limited. .

An object of the present invention is to improve the ejection performance of an ejector tool.

This problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are described in the dependent claims.

According to a first aspect of the invention, a method is described for removing chips from an adhesive film of a wafer film frame using a gripping tool, assisted by a stripping tool. The described method includes the steps of: (a) positioning the wafer film frame relative to the stripping tool such that a first chip of the wafer film frame is located above the working area of the stripping tool; (b) applying a negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool; and (c) (c1) activating a peeling tool to reduce adhesion of the first chip to the adhesive film; (c2) gripping the first chip with a gripping tool; (c3) the gripping tool; The first chip is removed by moving the gripped first chip away from the adhesive film. The method further comprises: (d) stopping the stripping tool so that no further interaction occurs between the stripping tool and the adhesive film; (e) the second chip of the wafer film frame (f) repositioning the wafer film frame relative to the stripping tool so as to be above the active area; and (f) repositioning the stripping tool to reduce adhesion of the second chip to the adhesive film. (f2) gripping the second chip by the gripping tool or the further gripping tool; (f3) moving the gripping tool or the further gripping tool away from the adhesive film together with the gripped second chip. The method includes the step of taking out the second chip. According to the invention, during the process of repositioning the wafer film frame, a negative pressure is additionally applied, at least temporarily, between the lower surface of the adhesive film and the upper surface of the stripping tool.

The method described is based on the recognition that for the repositioning of the wafer film frame it is not necessary to (completely) release the negative pressure between the lower side of the adhesive film and the upper side of the stripping tool. This ensures that when removing a chip, or more precisely in the time interval between the successive removals of two different chips, (i) a negative pressure (at the current ambient pressure) is applied before repositioning; (ii) after repositioning and before ejecting the second tip, in order to fully build up the negative pressure again, which is necessary or generated in conventional tip ejection methods. waiting times can be avoided or at least reduced.

Expressed clearly, in the method according to the invention, in order to (re)position the wafer film frame, the previously applied negative pressure is not released until ambient pressure is again reached, or at least It will not be completely removed. As a logical consequence, this negative pressure also does not need to be created (completely fresh) before removing the second chip. This provides a significant time advantage compared to known chip removal processes and a corresponding improvement in chip removal performance. This allows chips to be fed to the attacher more quickly and improves the actual mounting performance of the attacher.

Removal of the second chip may be carried out, as described above, with the gripping tool that has already taken out the first chip and which has meanwhile placed the first chip in the mounting position, or with a further or different gripping tool. obtain. In the second case, the first chip may 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 in 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 taken out and conveyed together by the whole mounting head to the mounting area of the automatic mounting machine, where they are placed in various The chips are placed one after another, ie without further removal of the chips, in a predetermined mounting position on the substrate or on the film of the artificial wafer.

In this specification, the concept "negative pressure" is to be understood as a pressure below the current ambient pressure or below the current atmospheric pressure. Properly expressed physically, negative pressure is a negative pressure difference with ambient pressure. The negative pressure can be created with any suitable type of pump known per se and can be regulated as required with suitable valves. Whenever a first negative pressure is stated herein to be greater than another second negative pressure, the first negative pressure is absolutely smaller compared to the second negative pressure. It means that it has a pressure value. In other words, smaller negative pressures are characterized by pressure values closer to ambient pressure than pressure values of larger negative pressures.

According to the invention, a 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 at atmospheric pressure rather than under negative pressure.

It is only important that the described sub-steps be coordinated and performed 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, the gripping of the chip may take place before, after or during operation of the stripping tool. Importantly, before moving the gripping tool or a further gripping tool away from the adhesive film, the adhesion of the chip in question to the adhesive film (top side) is ensured by (re)activation of the peeling tool, which the gripping tool is then It is only a matter of ensuring that the available gripping force is reduced to the extent that it can securely grip the chip and also retain the chip.

The described stripping tools preferably include a body or at least one component with a flat top surface. The (non-adhesive) lower side of the adhesive film can abut the upper side (assisted by negative pressure).

In this specification, a wafer is in particular a semiconductor chip on its adhesive film, depending on the application, (i) diced by a sawing process or (ii) a semiconductor pre-mounted on the adhesive film. It should be understood that it is a so-called wafer film frame with any of the chips. The wafer or wafer film frame further includes a frame covered with an elastic film, as mentioned at the outset. The frame of the wafer film frame may be a flat metal frame, in particular to avoid unnecessary height expansion, 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 and may in principle be manufactured from any material, such as steel and/or plastic. Additionally, the film may be stretched in a metal frame or grip ring, with the individual chips being somewhat spaced apart from each other.

Handling of the wafer film frame can be carried out, for example, by means of a robot or a clearly simpler handling device, which engages the frame with suitable grippers and by moving the grippers appropriately. , the wafer or wafer film frame is moved, for example only along a predetermined two-dimensional or three-dimensional trajectory.

The techniques described herein primarily relate to the removal of chips from wafer film frames, and not to the processing of semiconductor wafers (slices of semiconductor material) per se. Therefore, in this specification, the shortened concept of simply "wafer" is often used for "wafer film frame."

In this specification, a chip is to be understood as an electronic component that can be removed from a wafer and mounted. In particular, chips are unpackaged or "bare" electronic components that are primarily composed of semiconductor materials and are fabricated or manufactured with other chips on the same semiconductor wafer. Apart from the semiconductor material of the original semiconductor wafer, the chips can also have metallic terminal contacts formed simultaneously for all chips of the semiconductor wafer within the scope of appropriate post-processing. In the case of spherical terminal contacts, the chip may be a so-called flip chip ball grid array (FCBGA) without special packaging. Furthermore, the chip can also have electrically applied convex terminal contacts, which also include suitable electrically and thermally conductive bonding materials (solders). Generally, such components are called chip scale packages (CSPs). After mounting the unpackaged chip on a component carrier, e.g. a printed circuit board (PCB) or on an elastic film of an artificial wafer, the mounted chip may be optionally coated with suitable coatings and/or It can be protected from harmful environmental effects using potting resin. The potting compound may in this connection be an underfill material inserted under the mounted chip.

According to one embodiment of the invention, the stripping tool has at least one mechanical stripping element which, upon actuation of the stripping tool, presses the adhesive film from below and thus Lift locally.

The mechanical lifting of the adhesive film described has the advantage that a rapid and effective reduction of the adhesion can occur when the peeling element is activated accordingly. In this case, a reduction in adhesion can occur, inter alia, as a result of the actual adhesion area between the chip and the adhesive film being reduced due to a changed three-dimensional shape or curvature of the adhesive film. The modified three-dimensional shape or curvature can be produced simply by, during the described actuation of the (at least one) peeling element, the peeling element lifting from the body of the peeling tool and pressing the adhesive film from below. .

That is, actuation of the stripping tool may be performed by moving at least one mechanical stripping element upwardly from the body of the stripping tool, as described above. In this case, the adhesive film is locally lifted upwards and is thereby locally separated from the upper surface of the peeling tool or the upper surface of the body. Correspondingly, stopping the stripping tool includes retracting the at least one mechanical stripping element downwardly, at least partially, into the body of the stripping tool. In this case, the mechanical release element is preferably retracted so far downward that it no longer abuts the underside of the adhesive film, which is now no longer lifted up again. This prevents damage to the adhesive film and/or the release element when repositioning the wafer film frame.

According to a further embodiment of the invention, the mechanical peeling element is an ejector pin.

Typically, the pin has a very small end face which presses against the adhesive film from below during activation of the stripping tool, so that the adhesive bond area between the film and the chip is , can be reduced particularly greatly. As mentioned above, the tip of the ejector pin can lift or pierce the adhesive film, depending on the specific configuration of the method. In the latter case, the adhesive area between the adhesive film and the chip is reduced to zero.

According to a further embodiment of the invention, the mechanical peeling element is an ejector plate with an elongated top surface. This means that when the mechanical stripping element is actuated or lifted, the film in the area of the chip to be removed abuts an elongated and relatively narrow edge or web. This makes it possible to reduce local distortions of the film, especially outside the area of the original adhesive surface of the chip. Adjacent chips of the wafer film frame that have not yet been ejected are therefore unaffected or only slightly affected by the ejection of that chip. In particular, the adhesion is not compromised (prematurely) by ejection of the chip and the consequent undesired curvature of the adhesive film outside the area of the chip just ejected.

The stripping tool may preferably be a plurality of ejector plates, each having an elongated upper surface, arranged parallel to each other and individually actuatable or liftable. By sequentially actuating or lifting different ejector plates, it is possible to reduce the adhesion of the chip in different adhesion part areas sequentially, thus obtaining an effective reduction of the adhesion over the entire adhesion area of the chip. .

According to another embodiment of the invention, the stripping tool has an energy source that transfers energy to the adhesive film in its active area, thereby reducing the adhesive strength of the adhesive film.

In this case, energy can be transferred contactlessly to the adhesive film in the form of electromagnetic radiation. The radiation may include visible or non-visible light, such as light in the infrared spectral region. For example, the energy source may include at least one laser or light emitting diode (LED). The energy source may further include a radiolucent contact window against which the adhesive film is abutted by an applied negative pressure. 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.

The energy may be thermal energy and is locally transferred without contact in the form of radiation, ie electromagnetic radiation with very long wavelengths. Alternatively, or in combination, thermal energy may 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 a negative pressure to the underside of the adhesive film using openings in or beside the heating or heatable surface. The heating or heatable surface may comprise silicon carbide, for example. This is a material that advantageously allows heating with a rapid temperature gradient in time.

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 stripping tool during the entire repositioning process. In simple terms, this means that at least in the time frame between the removal of the first chip and the removal of the second chip, the negative pressure between the bottom surface of the adhesive film and the top surface of the stripping tool is not released. Or, at least, it means that it is not completely released. This has the advantage that in order to obtain the necessary negative pressure to ensure ejection of the second chip, less time is required to build up this necessary negative pressure before ejecting the second chip. has.

According to a further embodiment of the invention, during the entire repositioning process, the negative pressure applied between the lower side of the adhesive film and the upper side of the stripping tool can be used to remove the first chip and/or to remove the second chip. less than the negative pressure applied between the bottom surface of the adhesive film and the top surface of the stripping tool during chip removal. This has the advantage that the repositioning is not or only slightly hindered by the pneumatic adhesion of the adhesive film to the top surface of the body, which is disadvantageous during positioning.

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. (i) the highest possible negative pressure during positioning to reduce the time interval of negative pressure changes; and (ii) to allow the wafer film frame to move as freely as possible relative to the stripping tool. The optimum compromise between the lowest possible negative pressure during positioning of the can be easily determined by experiment depending on the particular application. In other words, it is only necessary to observe at what point a sufficiently good relative mobility is obtained when the negative pressure is gradually lowered.

According to a further embodiment of the invention, the difference between (i) the negative pressure when removing the first chip and/or the second chip and (ii) the negative pressure when repositioning is: At least in part due to leakage. This has the advantage that there is no need to use complex pressure control mechanisms to achieve a reduction in negative pressure during positioning. In particular, reducing the negative pressure for repositioning can be achieved by simply stopping the operation of the pump and/or (temporarily) pneumatically uncoupling the pump from the stripping tool and/or the adhesive film by means of a shut-off valve. obtained by

The expression "leakage" in this context means in particular an air flow caused by the inflow of air from the surroundings into a spatial region of negative pressure. In this case, the larger the opening or cross-section of the corresponding leak, the more the negative pressure after removing the first chip and/or the second chip will be up to the negative pressure required for trouble-free repositioning. Declines quickly.

According to a further embodiment of the invention, the course of the negative pressure over time between the lower side of the adhesive film and the upper side of the stripping tool is (actively) controlled. Active control can be effected, for example, by a corresponding control of a pump creating a negative pressure and/or by a suitable pneumatic control valve between such a pump and the peeling tool or the adhesive film.

The described active control makes it possible to keep the entire process under control with pneumatic pressure in an advantageous manner, especially if the negative pressure changes (to a large extent) in the various stages of the described method. As a result, high reliability of the process can be guaranteed despite high removal performance.

According to a further embodiment of the invention, the course of the negative pressure over time is controlled using a pressure sensor. With the described control (in a closed control loop), the time profile of the negative pressure can be adapted with high precision to a predetermined setpoint pressure profile. This provides a further improved compromise between high removal performance and high process reliability.

According to a further embodiment of the invention, the course of the negative pressure over time is actively controlled using an analog pneumatic valve. The analog air valve described may preferably be arranged between the pump creating the negative pressure and the stripping tool or the adhesive film.

The analog pneumatic valve described may be any pneumatic device capable of causing a pressure change by open-loop control or closed-loop control intervention. An analog pneumatic valve may in particular be a valve with two inlets and one outlet, one inlet being connected or connected pneumatically to the pump and the other inlet to the surrounding environment. The outlet can in particular be connected pneumatically to a negative-pressure spatial region between the peeling tool and the adhesive film. Analog pressure changes can be made through the ratio of flow cross-sections or flow resistances between the two inlets.

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

In other words, with the method described, two or more chips can be removed quickly, ie with high removal performance. In particular, the method can be repeated until a desired number of chips have been removed from the wafer film frame. The desired number of chips may be the total number of chips remaining on the wafer film frame, or it may be a specific number of chips that need to be removed for a particular packaging operation.

According to a further aspect of the invention, an apparatus is described for removing chips from an adhesive film of a wafer film frame, in particular by carrying out a method of the type described above. The described apparatus includes: (a) a stripping tool configured to reduce the adhesion of the chips to the adhesive film in the active area; (b) a plurality of chips of the wafer film frame positioned in series above the active area; (c) a negative pressure configured to apply a negative pressure between the lower surface of the adhesive film and the upper surface of the stripping tool; a forming device; and (d) (d1) activating a peeling tool such that adhesion of the chip to the adhesive film is reduced; (d2) gripping the chip with a gripping tool; and (d3) gripping the chip with the gripping tool. a mounting head having at least one gripping tool each configured to remove one chip by moving the chip away from the adhesive film; While positioning the wafer film frame after taking out the first chip and before taking out the second chip, the negative pressure forming device at least temporarily connects the lower surface of the adhesive film with the peeling tool. The removal tool is configured to continuously apply a negative pressure between the adhesive film and the upper surface, and each of these removals is performed while applying a negative pressure between the lower surface of the adhesive film and the upper surface of the peeling tool.

The described chip removal device is also based on the recognition that it is not always necessary to (completely) release the negative pressure between the bottom surface of the adhesive film and the top surface of the stripping tool in order to position the wafer film frame. ing. This ensures that, in the time interval between successive removals of two different chips, (i) the negative pressure is completely released (to their respective ambient pressure) before positioning the wafer film frame, and (ii) after positioning. , and the waiting time required in conventional chip removal devices in order to fully establish the negative pressure again before further chip removal can be avoided or at least reduced.

According to an embodiment of the invention, the device for generating negative pressure has a pump, a controllable valve and a control unit, with the control unit the pump and/or the controllable valve are configured to It can be controlled to vary the negative pressure between the lower surface and the upper surface of the stripping tool.

Due to the control triggered by the control unit, it is advantageously possible to keep the entire process of successive removal of several chips under control (actively), even if the negative pressure can vary (largely). be. As a result, high reliability of the process can be guaranteed despite high removal performance.

According to a further embodiment of the invention, the device further comprises a pressure sensor, the pressure sensor being communicatively coupled to a control unit, the control unit configured to determine a predetermined time course of the negative pressure. The information technology is configured to control the pump and/or the controllable valve on the basis of the pressure measurement of the pressure sensor so that the pressure measurement occurs.

The pressure sensor may be a component of a closed control loop. This makes it possible to adapt the negative pressure profile over time to a predetermined setpoint pressure profile with particularly high precision. This provides an even better compromise between high removal performance and high process reliability.

According to a further aspect of the invention, a mounting system for mounting a chip on a substrate is described. The described mounting system includes (a) a device for picking up the chips as described above, (b) a first pickup device for picking up the wafer film frame, and (c) a device for picking up the substrate to be mounted. It has a second pickup device. A mounting head with at least one gripping tool is configured to remove the chip from the wafer film frame and place it on the substrate.

The described mounting system is characterized by the fact that the above-mentioned chip ejecting device, which is a component of the mounting system, can provide a high ejection performance, i.e., from the wafer film frame to the substrate within a predetermined time unit. It is based on the recognition that the number of chips that can be placed is no longer determined or limited by the air pressure relief that can occur within the chip removal device.

The first pick-up device is preferably mechanically connected to the positioning device. Thereby, while positioning the picked-up wafer film frame, the first pick-up device is also moved together with the wafer film frame.

The placement of the chips is performed not only directly from the wafer film frame onto the substrate, but also indirectly by using at least one additional chip handling device that performs the final placement of the chips on the substrate. is also possible. In this connection, the chip handling device can include, for example, a further mounting head and/or a temporary storage location for the chips.

In accordance with a further aspect of the invention, a computer program product is described for operating an apparatus for removing chips from an adhesive film of a wafer film frame. In this case, the device is in particular a device of the type mentioned above. The computer program, when executed by the data processing unit, is configured to carry out the above-described method for removing chips from the adhesive film of the wafer film frame.

Such a computer program is herein defined as a program element containing instructions for controlling a computer system to suitably adjust the functioning of the system or method in order to obtain the effects associated with the method according to the invention. , computer program product and/or computer readable medium.

The computer program may be implemented as computer readable instruction code in any suitable programming language, such as JAVA, C++, or the like. The computer program may be stored on a computer readable storage medium (CD-ROM, DVD, Blu-ray disc, removable drive, volatile or non-volatile memory, internal memory/processor, etc.). The instruction code can be used to program a computer or other programmable device, particularly a control computer of an automatic installation machine, to perform the desired functions. Further, the computer program can be provided over a network such as the Internet, and can be downloaded by a user from the network as needed.

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

The invention described herein can also be practiced using a "cloud" network with corresponding virtual storage space and corresponding virtual computing power.

It is noted that embodiments of the invention have been described in connection with various subject matter of the invention. In particular, some embodiments of the invention have been described in apparatus claims, and other embodiments of the invention have been described in method claims. However, unless expressly stated otherwise, in addition to combinations of features belonging to one type of object of the invention, any combination of features belonging to different types of object of the invention is also possible. , will be readily apparent to those skilled in the art after reading this specification.

Further advantages and features of the invention will become apparent from the following exemplary description of the presently preferred embodiments.

FIG. 3 illustrates an apparatus for ejecting chips from an adhesive film of a wafer film frame assisted by an ejector tool having a plurality of ejector pins, according to an embodiment of the present invention. With respect to the removal of chips from the adhesive film of the wafer film frame, (i) movement of the gripping tool, (ii) movement of (at least) one ejector pin, and (iii) shadow applied between the adhesive film and the ejector tool. FIG. 3 is a diagram showing the interaction between pressures.

The embodiments described below are only a limited selection of possible embodiment variants of the invention. In particular, it is possible to suitably combine the features of the individual embodiments, so that a large number of different embodiments are clearly disclosed to those skilled in the art, with variations of the embodiments explicitly shown herein. It is considered that

In addition, spatial concepts such as "front" and "back", "top" and "bottom", "left" and "right", etc., refer to the relationship of one element to another, as shown in the diagram. It should be pointed out that it is used to describe. Thus, spatial concepts may apply in directions different from those illustrated in the figures. However, all such spatial concepts are related to the orientation shown in the drawings for ease of explanation, and each illustrated device, when used, is It is self-evident that this is not necessarily restrictive since it may take different directions.

FIG. 1 shows an apparatus 100 for ejecting a chip 195 from an adhesive film 192 of a wafer film frame 190 with the aid of an ejector tool 110, according to one embodiment of the invention. The basic principles of ejecting the chip 195 with the aid of the ejector tool 110 are known per se and will not be explained from scratch here. In particular, as mentioned above, it is known to use an ejector plate in place of the ejector pin 114 shown in FIG. The non-mechanical reduction of the adhesive force using radiation and/or heat is also known per se to the person skilled in the art, so that it will not be mentioned in detail again.

The wafer film frame 190 has a frame structure 194, as is known, and an adhesive film 192 is applied to the frame structure 194. Chip 195 is located on the adhesive surface of film 192. In order to remove the chip 195, the wafer film frame 190 is moved at least in the or along the y direction, so that the chip 195 to be ejected is located directly above the ejector tool 110. More precisely, the chip 195 to be ejected is located directly above the ejector pin 114 of the ejector tool 110.

The apparatus 100 further includes a mounting head 150 that is movable above the wafer film frame 190 using a positioning system, not shown. The mounting head 150, which can be a placement head known per se, has at least one gripping tool 154 configured in the form of a suction pipette, which gripping tool 154 can be operated using a linear drive, not shown. and is movable along the z direction (perpendicular to the x and y directions shown in FIG. 1) perpendicular to the chassis 152 of the mounting head. At the beginning of the chip removal process, the gripping tool 154 is positioned such that its front, lower end surface with a suction port, not shown in FIG. 1, directly abuts the upper surface of the chip 195.

Removal of the chip 195 is performed in a known manner by (a) moving the ejector pin 114 upwardly relative to the body 112 of the ejector tool 110, and (b) simultaneously and to the same extent moving the gripping tool 154 upwardly. It is done by If the adhesive film 192 is penetrated or bent, the adhesion of the chip 195 to the film 192 is lost or degraded. The negative suction pressure created through the suction tube of the gripping tool 154 is not to be confused with the negative pressure between the film 192 and the ejector tool 112 described below, and again in a known manner, the tip 195 154 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, is created in a known manner according to the embodiment shown in the figure. Then, the ejector pin 114 pierces the film 192 and functions in such a way that the surface is not simply lifted. Alternatively, if sufficient negative pressure exists on the lower surface 192a of the film 192, the ejector pin 114 may cause the film 192 to be lifted only locally directly at the tip of the ejector pin 114, causing the adhesive upper surface of the film 192 and the corresponding It may serve to significantly reduce the adhesion area and therefore the adhesion force between the chip 195 and the chip 195 . The described negative pressure is generated by the negative pressure generating device 140 and is applied to the lower surface 192a of the adhesive film 192 through an opening provided on or in the upper surface 112a of the main body 112 (not shown).

As is clear from FIG. 1, the negative pressure generating device 140 includes a pump 142, which is connected to a first air inlet 144a of a controllable valve 144 through an air conduit, which is not referenced. Connected by pneumatics. The second air inlet 144 of the controllable valve 144b is pneumatically connected to the surrounding environment. The air outlet 144c of the controllable valve 144 is pneumatically connected to the air inlet 110a of the interior space of the body 112.

According to the embodiment shown in this figure, the controllable valve 144 is a so-called analogue valve and is controlled by a control unit 146 through control lines shown in dashed lines and not referenced. According to the embodiment shown in this figure, 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, as controlled by the control unit 146. is adjusted. The larger this ratio, the smaller the flow of intake air 145 that must enter the controllable valve 144 through the second air inlet 144b and be pumped out by the pump 142. A corresponding proportion of the suction power of the pump 142 does not contribute to the creation or increase of negative pressure on the lower surface 192a of the film 192. According to the techniques described herein, the negative pressure applied to the lower surface 192a of the film 192 can be arbitrarily adjusted by the control unit 146 as a function of time.

According to the embodiment shown in this figure, during the actual ejection of the chips 195, a greater negative pressure than in the time frame in which the wafer film frame 190 is repositioned or moved relative to the ejector tool 110 in the xy plane. is set. Therefore, (a) after positioning the wafer film frame 190 and before removing the chip 195, the desired negative pressure is completely renewed, and/or (b) after removing the chip 195, and , it is no longer necessary to create a negative pressure completely before positioning the wafer film frame 190 ("toward the next chip 195 to be ejected"). This reduces the length of the time window in which the described pressure changes occur and allows a corresponding improvement in the removal performance.

According to the embodiment shown in this figure, the device 100 further includes a pressure sensor 120 located inside the body 112. The pressure sensor 120 always measures the current negative pressure and transmits the corresponding pressure measurement to the control unit 146 via a communication line (not referenced) shown in broken lines. The control unit 146 can control the control unit 146 at any point in the method described herein for ejecting a plurality of chips 195 through corresponding closed-loop control intervention for such control of the analog controllable valve 144. The function is such that a desired negative pressure is always applied between the lower surface 192a of the adhesive film 192 and the upper surface 112a of the main body 112.

The operator can configure and/or monitor the entire retrieval process through the display and operating terminal 160.

FIG. 2 shows (i) the movement of the gripping tool 154, (ii) the movement of the two ejector pins 114, and (iii) the adhesive film 192 and the ejector tool 110 with respect to the removal of the chip 195 from the adhesive film 192 of the wafer film frame. It shows the interaction between negative pressure dp applied between dp and dp. FIG. 2 only shows time frames in which the wafer film frame is not moving relative to the ejector tool 110 and assumes a position in which the chip to be ejected is on the underside of the gripper tool 154.

The vertical movement of the gripping tool 154 as a function of time t is visualized by the dashed line labeled M1. The course of the movement of the two ejector pins 114 in FIG. 2, also moving exclusively in the vertical direction, is shown below on the same time axis t and is designated with the reference symbol M2. The bottom graph of FIG. 2 shows, again on the same time scale, the course of the negative pressure applied between the adhesive film 192 and the ejector tool 110, the course being marked with the reference P1. . As is clear from FIG. 2, in the embodiment described in this figure, the negative pressure is never zero, but varies between two boundary values -300 mbar and -750 mbar. Naturally, other negative pressure threshold values and/or other negative pressure profiles can also be selected depending on the application. For the present invention, it is only necessary that movements not shown in FIG. 2 are not fully performed without applying negative pressure.

In the embodiment shown, the ejection of the chip 195 begins at time t0 by applying a relatively high negative pressure between the adhesive film 192 and the ejector tool 110. In this case, the negative pressure increases from -300 mbar to -750 mbar in the time frame from t0 to time t1 and is then maintained for a relatively long time interval (until time t12 after removal of the chip 195).

As is clear from FIG. 2, according to the embodiment shown in this figure, at time t1, the gripping tool 154 begins to descend downwards. At this time, the descending speed determines the slope of the corresponding first section of the curve M1. At the same time, ejector pin 114 begins to move upward. At time t2, the tip of the ejector pin 114 comes into contact with the lower surface of the adhesive film 192.

At time t3 (the maximum negative pressure of -750 mbar has long been reached), the gripping tool 154 is moved towards the chip 195 with a reduced downward speed. It is known to those skilled in the art to reduce the rate of descent to avoid the gripping tool 154 impacting the chip 195 hard, and therefore will not be discussed in detail herein.

At time t4, the end face of the gripping tool 154 configured as a suction pipette comes into contact with the upper surface of the tip 195 and the vertical downward movement of the suction pipette 154 is stopped. At the same time, a negative suction pressure is created in the suction tube of the suction pipette 154 between the suction pipette 154 and the tip 195 in a known manner. The beginning of the formation of negative suction pressure at time t4 is indicated in FIG. 2 by arrow 272. At time t5, highlighted by arrow 274, the maximum negative suction pressure at which the tip 195 is held is or will be reached.

At time t6, the movement of the tip 195 from the adhesive film 192 to the suction pipette 154 causes both ejector pins 114 to move further upwards, where, according to the embodiment shown in the figure, they pierce the adhesive film 192; Begin by pressing tip 195 against the front end of aspiration pipette 154 . Immediately thereafter, at time t7, a corresponding upward movement of the suction pipette 154 begins. Thereafter, the ejector pin 114 and the suction pipette 154 similarly move upward until time t8.

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

At time t10, the suction pipette 154, together with the gripped tip 195, is lifted upwards, first slowly and then more rapidly from time t11 onwards. This completes the removal of the chip 195 "from the perspective of the wafer film frame."

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 negative pressure between the ejector tool 110 and the adhesive film 192 is released. At time t13, a final negative pressure of -300 mbar is reached. Ejector pin 114 reaches its starting position at time t14.

After time t14, the wafer film frame can be moved horizontally relative to the ejector tool 110 such that the next chip 195 is located above the ejector tool 110. The procedure described above may then be performed again to remove the next chip 195.

Note that the word "having" does not exclude other elements, and "a" does not exclude a plurality. It is also possible to combine elements described in connection with different embodiments. It is also noted that reference signs in the claims shall not be construed as limiting the scope of protection of the claims.

100 Device for removing chips 110 Peeling tool/ejector tool 110a Air inlet 112 Body 112a Top surface 114 Mechanical peeling element/ejector pin 120 Pressure sensor 130 Positioning device 140 Negative pressure creation device 142 Pump 144 Controllable valve 144a First Air inlet 144b Second air inlet 144c Air outlet 145 Intake air 146 Control unit 150 Mounting head 152 Chassis 154 Gripping tool/suction pipette 160 Display and operation terminal 190 Wafer film frame 192 Adhesive film 192a Bottom surface 194 Frame structure 195 Chip 272 Suction shade Start of pressure application 274 Achievement of suction negative pressure 276 End of transfer of tip from adhesive film to suction pipette dp Negative pressure t Time M1 Movement transition of gripping tool M2 Movement transition of ejector pin P1 Time course of negative pressure t# Time point (#=0, 1, 2,..., 14)

Claims (17)

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 stripping tool (110), the method comprising:
The wafer film frame (190) is placed relative to the stripping tool (110) such that the first tip (195) of the wafer film frame (190) is located above the working area of the stripping tool (110). positioning, in the area of action, the stripping tool (110) interacts with the adhesive film (192) to promote adhesion of the first chip (195) to the adhesive film (192); lowering step;
applying negative pressure between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110);
(i) actuating the peeling tool (110) to reduce adhesion of the first chip (195) to the adhesive film (192); (ii) removing the first chip (195) by the gripping tool (154); the first chip (195) by gripping the chip (195); and (iii) moving the gripping tool (154) away from the adhesive film (192) together with the gripped first chip (195). taking out the chip (195);
stopping the stripping tool (110) so that no further interaction occurs between the stripping tool (110) and the adhesive film (192);
repositioning the wafer film frame (190) relative to the stripping tool (110) such that a second tip (195) of the wafer film frame (190) is located above the working area of the stripping tool; step; and
(i) reactivating the stripping tool (110) to reduce adhesion of the second chip (195) to the adhesive film (192); (ii) the gripping tool (154) or further gripping; gripping said second chip (195) by a tool; and (iii) gripping said gripping tool (154) or said further gripping tool together with said gripped second chip (195) and said adhesive film (192); ejecting the second chip (195) by moving it away from the second chip (195);
During the process of repositioning the wafer film frame (190), at least temporarily, a negative pressure is created between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the stripping tool (110). How to add more. The stripping tool (110) has at least one mechanical stripping element (114), which upon actuation of the stripping tool (110) removes the adhesive film (192). 2. Method according to claim 1, characterized in that the adhesive film (192) is locally lifted by pressing from below. 3. The method of claim 2, wherein the mechanical stripping element is an ejector pin (114). 3. The method of claim 2, wherein the mechanical peeling element is an ejector plate having an elongated top surface. 4. The stripping tool comprises an energy source, said energy source transmitting energy to said adhesive film (192) in its area of action, thereby reducing the adhesive strength of said adhesive film (192). The method described in Section 2. 2. The method of claim 1, wherein a negative pressure is applied between the lower surface (292a) of the adhesive film (292) and the upper surface (112a) of the peeling tool (110) throughout the repositioning process. Throughout the repositioning process, a negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) is applied to the first chip (195). negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) during the removal of the adhesive film (192) and/or the removal of the second chip (195); 2. The method of claim 1, wherein the method is less than . The difference between (i) the negative pressure when taking out the first chip (195) and/or the second chip (195) and (ii) the negative pressure when repositioning is at least 8. The method of claim 7, in part due to leakage. 2. The method according to claim 1, wherein the time course of the negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110) is controlled. 10. The method of claim 9, wherein the negative pressure profile over time is controlled in a closed loop using a pressure sensor (120). 10. The method according to claim 9, wherein the negative pressure profile over time is actively controlled using an analog pneumatic valve (114). Furthermore, after taking out 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);
The wafer film frame (190) is placed relative to the stripping tool (110) such that the third tip (195) of the wafer film frame (190) is located above the working area of the stripping tool (110). repositioning step;
(i) activating the stripping tool (110) again to reduce adhesion of the third chip (195) to the adhesive film (192); (ii) the gripping tool (154) or a further gripping tool; and (iii) removing the gripping tool (154) or the further gripping tool from the adhesive film (192) together with the gripped third chip (195). ejecting the third chip (195) by moving it away;
During the process of repositioning the wafer film frame (190), at least temporarily, a negative pressure is created between the lower surface (292a) of the adhesive film (192) and the upper surface (112a) of the stripping tool (110). 2. The method of claim 1, wherein: An apparatus (100) for removing a chip (195) from an adhesive film (192) of a wafer film frame (190), in particular carrying out the method according to claim 1, said apparatus comprising:
a peeling tool (110) configured to reduce the adhesion of the chip (195) to the adhesive film (192) in an active area;
The wafer film frame (190) is successively positioned relative to the stripping tool (110) such that a plurality of chips (195) of the wafer film frame (190) are successively positioned above the working area. a positioning device (130) for;
a negative pressure generating device (140) configured to apply a negative pressure between a lower surface (192a) of the adhesive film (192) and an upper surface (112a) of the peeling tool (110); and
(i) activating the peeling tool (110) such that adhesion of the chip (195) to the adhesive film (192) is reduced; (ii) gripping the chip (195) by a gripping tool (154); and (iii) configured to remove one chip (195) each by moving said gripping tool (154) with said gripped chip (195) away from said adhesive film (192). a mounting head (150) equipped with at least one gripping tool (154);
The negative pressure forming device (140) is configured to position the wafer film frame (190) after taking out the first chip (195) and before taking out the second chip (195). , configured to continue to apply, at least temporarily, a negative pressure between the lower surface (192a) of said adhesive film (192) and the upper surface (112a) of said peeling tool (110), and their removal: The apparatus (100) is carried out with negative pressure applied between the lower surface (192a) of the adhesive film (192) and the upper surface (112a) of the peeling tool (110), respectively. The device (140) for generating negative pressure has a pump (142), a controllable valve (144) and a control unit (146), using the control unit to control the pump (142) and/or the A controllable valve (144) can be controlled such that the negative pressure between the lower surface (192a) of the adhesive film (190) and the upper surface (112a) of the peeling tool (110) can be varied; Apparatus (100) according to claim 13. Furthermore, the control unit (146) has a pressure sensor (120) communicatively coupled to the control unit (146), and the control unit (146) is configured to control the pressure sensor (120) so that a predetermined time course of the negative pressure occurs. 15. Information technology configured to control the pump (142) and/or the controllable valve (144) based on pressure measurements of the pressure sensor (120). Apparatus (100). A mounting system for mounting a chip (195) on a substrate,
A device (100) for removing a chip (195) according to claim 13;
a first pick-up device for picking up the wafer film frame (190); and
It has a second pickup device for picking up the board to be mounted,
A mounting system, wherein a mounting head (150) has at least one gripping tool (154) and is configured to remove the chip (195) from the wafer film frame (190) and place it on the substrate. 14. A computer program for operating an apparatus (100) for removing chips (195) from an adhesive film (192) of a wafer film frame (190), in particular an apparatus (100) according to claim 13, comprising: a data processing unit ( 146), the computer program being adapted to implement the method of claim 1 when the computer program is executed by 146).