Press and method for encapsulating electronic components with at least two individually controllable actuators

Abstract

Press for encapsulating electronic components mounted on a carrier, comprising: - at least two pressing elements which can be adjusted relative to one another in a pressure direction towards or away from one another for holding at least two cooperating moulded parts, - a drive system for driving the relative adjustment of the at least two pressing elements, - several adjustment sensors for detecting the relative pressure direction of the pressing elements in the pressure direction of the at least two pressing elements at different locations of the at least two pressing elements, and - an intelligent controller connected to the drive system, wherein the intelligent controller is configured to control the drive system, wherein at least one of the at least two molded parts is provided with at least one mold cavity which is recessed in a contact side to enclose at least one electronic component placed on the carrier, and the contact surface of this at least one molded part at least partially encloses the mold cavity in order to fit onto the carrier in a closed position of the molded parts in a media-tight manner, wherein the drive system comprises a plurality of individually controllable actuators to exert forces in the pressure direction of the at least two pressing elements at a plurality of locations, and wherein the intelligent controller is further connected to the plurality of displacement sensors, wherein the intelligent controller is configured to dynamically control the actuators of the drive system over time based on the displacement measurements acquired by the displacement sensors in order to reduce the displacement measurements by changing the pressure distribution during the feeding of molding material into the mold cavity, wherein the mold parts are in a closed position and the pressing elements exert pressure on one another.

Description

[0001] The invention relates to a press for encapsulating electronic components mounted on a carrier. The invention also relates to an actuator set for converting a press for encapsulating electronic components mounted on a carrier into a press according to the present invention, as well as to a method for encapsulating electronic components mounted on a carrier.

[0002] The encapsulation of electronic components mounted on a carrier with an encapsulating material is a well-known technique, as described, for example, in JP S64-57724 A, US 2007 / 0176317 A1, or US 2015 / 0364456 A1. Such electronic components are encapsulated on an industrial scale, typically using a curing epoxy to which a filler is added. There is a market trend toward the simultaneous encapsulation of larger quantities of relatively small electronic components. Electronic components such as semiconductors (chips, although LEDs are also considered semiconductors in this context) can be considered for this purpose, as these are generally becoming increasingly smaller.After the encapsulation material has been applied, the co-encapsulated electronic components are contained within an enclosure (chip package or "package") arranged on one side, but sometimes on both sides, of the carrier. The encapsulation material often takes the form of a flat layer bonded to the carrier. The carrier may consist of a lead frame, a multilayer carrier—partially made of epoxy—(also called a board or substrate, etc.), or another support structure such as delicate silicon, glass, or ceramic carriers or wafers, or another support structure.

[0003] During the encapsulation of electronic components mounted on a carrier, encapsulation presses are usually used according to the prior art. These presses drive two mold parts, with one or more mold cavities being cut out in at least one of the mold parts. After the carrier with the electronic components has been placed between the mold parts for encapsulation, the mold parts can be moved towards one another by moving pressing elements to which the mold parts are connected, e.g. in such a way that these clamp the carrier. A normally heated liquid encapsulation material can then be fed into the mold cavities, usually by means of injection molding. Alternatively, it is also possible to introduce the encapsulation material into the mold cavity before the mold parts are closed, e.g. as granules, sheets or as a liquid, whereupon the components to be molded are pressed into the encapsulation material.Such a compression molding process represents an alternative to transfer molding. Epoxy (also known as synthetic resin) is used as the encapsulating material, which is generally filled with a filler. After at least partial (chemical) curing of the encapsulating material in the mold cavity(ies), the carrier containing the encapsulated electronic components is removed from the encapsulation press. The encapsulated products can then be separated during further processing. This encapsulation process is practiced on a large industrial scale and enables highly controllable encapsulation of electronic components.A problem during the encapsulation process and subsequent processing of molded electronic components is that control over the dimensional accuracy of the molded product is not always sufficient to meet increasing market demands for accuracy. Furthermore, there is a risk of carrier damage during the molding process.

[0004] The object of the present invention is to provide an alternative method and apparatus that retain the advantages of the prior art method for encapsulating electronic components, but provide improved process control, resulting, among other things, in better control over the dimensions of the encapsulated electronic components and / or limiting the risk of damage to the carriers. By clamping the components before applying encapsulation material, the invention is also suitable for encapsulating exposed electronic components.

[0005] To this end, the invention provides a press for encapsulating electronic components mounted on a carrier, comprising at least two pressing elements which are adjustable relative to one another for holding at least two cooperating mold parts, a drive system for driving the relative adjustment of the pressing elements and an intelligent control system connected to the drive system of the pressing elements, wherein the intelligent control system is designed to control the drive system of the pressing elements, wherein the drive system comprises at least two individually controllable actuators which make it possible to change the distribution of the pressure exerted by the drive system on at least one of the pressing elements in a position of the pressing elements in which the pressing elements exert pressure on one another (i.e. after the closure of the mold parts carried by the pressing elements).The intelligent control of the press of the present invention is further connected to a plurality of displacement sensors for detecting the relative displacement of the press elements at different locations, wherein the intelligent control is configured to dynamically control the actuators of the drive system over time based on the measured values ​​detected by the displacement sensors.

[0006] The press according to the present invention makes it possible to substantially maintain the relative alignment of the pressing elements, and thus also of the cooperating mold parts held by the pressing elements, regardless of external loads and fluctuations in the distribution of the loads exerted on the pressing elements (or the loads exerted on the mold parts and transmitted to the pressing elements). In the position of the pressing elements in which the pressing elements exert pressure on one another, the mold parts are in a closed position. An external influence exerting pressure can be the supply of (liquid) molding material into a mold cavity or cavities of at least one of the mold parts.At the beginning of the mold material feed, only the sprues and subsequently a portion of the mold cavity(s) are filled with liquid mold material, so that the mold material exerts pressure on the molded parts only at these points (which is transferred to the pressing elements). These local and changing loads on the pressing elements lead to (limited, on the order of micrometers) local displacements of the molded parts (and thus also of the pressing elements supporting the molded parts), which, without further measures, would lead to corresponding inaccuracies in the dimensions of the molded product to be formed and to locally increased pressure on the supports.The present invention now enables the detection of any (limited) local adjustments of the pressing elements and a correction / compensation of these adjustments by changing the distribution of the pressure exerted by the drive system on at least one of the pressing elements, thus adjusting the pressing elements (and thus the mold parts attached to the pressing elements) to the original (desired) position relative to one another. Furthermore, with the press according to the invention, the clamping force acting on the carrier is better controlled, since pressure peaks acting on the carrier due to local adjustments of the pressing elements (and thus the mold parts attached to the pressing elements) can be avoided or at least limited. The advantage of better control of the (maximum) pressure on the carrier is, for example, that cracks in sensitive silicon or glass (or other fragile carriers or wafers) can be avoided.Improved control of the clamping force distribution also ensures better control of the venting (for venting the gases from inside the cavity), since the improved position control of the compression elements (and thus the mold parts attached to the compression elements) better maintains the intended dimensions of the vent openings. Furthermore, with better control of the orientation of the compression elements (and thus the mold parts attached to the compression elements), there is a reduced risk of mold material escaping between the mold parts ("bleeding" or "flash"). The present invention thus results in more control over the resulting dimensions of the molded products, a reduced risk of damage to the carrier, and better process control (e.g., proper venting function and avoidance of bleeding / flash).It must be understood that the external loads acting on the pressing elements can change not only during the feeding of molding material into at least one of the molded parts. The same situation can also occur during the curing process (or part of the curing process) of the molding material. Similarly, local changes in the relative positioning of the pressing elements during (part of) the curing of the molding material can be compensated for by changing the distribution of the pressure exerted by the drive system on at least one of the pressing elements through the at least two individually controllable actuators.

[0007] If the drive system of the press comprises at least three individually controllable actuators, e.g. a drive cylinder in combination with at least two press cylinders, the adjustability of a press element in two dimensions is possible, which further increases the control over the dimensions of the electronic components to be molded.

[0008] The individually controllable actuators can be formed by pressure cylinders, usually hydraulic pressure cylinders. Alternatively, one or more of the individually controllable actuators could be designed as spindles. These types of actuators are suitable for the pressure requirements in a molding press, as long as the direction of the pressure exerted by the actuators corresponds to the adjustment direction of the actuators. Regarding the positioning of the individually controllable actuators, at least two of the pressure cylinders preferably contact the pressing element off-center to allow the alignment of the pressing element with the actuators to be changed. The actuators can act on the opposing pressing elements, but from a regulatory and structural point of view, it is simplest if at least three actuators, such as pressure cylinders, interact with a single pressing element.An alternative possibility is to use four or more cylinders interacting with a single pressing element.

[0009] Since the accuracy requirements regarding geometry and clamping force distribution are high in the field of molding electronic components, the displacement sensors preferably have a sensitivity for relative displacements in the micrometer (µm) range. Displacement sensors can ensure such accuracy and can be combined with UOD (Unwanted Object Detection) to detect unwanted and / or unexpected materials during mold closing, e.g., objects that are not intended to be present where they are detected. One possible solution for such sensors is the relatively inexpensive analog inductive proximity switches or analog capacitive proximity switches used as displacement sensors. A more complex alternative is the installation of incremental linear optical sensors or Hall sensors with high-precision length measuring systems.

[0010] The present invention relates not only to the press as such, but also to the press in which the pressing elements hold at least two mold parts, wherein at least one of the mold parts is provided with at least one mold cavity which is recessed in a contact side for enclosing at least one electronic component placed on the carrier, wherein the contact surface of this mold part at least partially encloses the mold cavity in order to fit onto the carrier in a media-tight manner when the mold parts are in a closed position. A mold part can also include a supply channel for molding material which is recessed in the contact surface of the mold part provided with the mold cavity. Such a supply channel is also referred to as a "casting channel."

[0011] The press with molded parts can also comprise feed means equipped with at least one piston for exerting pressure on a liquid encapsulating material such that the encapsulating material is forced toward the mold cavity surrounding the electronic component. This type of press is also referred to as an "injection press." The press according to the invention allows for higher product specifications and a limited risk of damage to the carriers using molded parts according to the prior art, thus eliminating the need for adaptation / conversion of standard molded parts. This limits the costs required to improve manufacturing accuracy and process control.

[0012] The press with molded parts can further comprise release means to facilitate the detachment of the at least one molded part, which is provided with at least one mold cavity recessed in a contact side for enclosing at least one electronic component placed on the carrier. By using such release means, the contact side is formed by the contact surface of the release means and the contact surface of the at least one molded part with which the release means interact. By providing the release means, the detachment of the molded part provided with the mold cavity from an encapsulated arrangement of electronic components mounted on a carrier is facilitated. Preferably, the release means are designed to interact with the contact side of the molded part directly below the position at which the sprues are located.It is even more preferred if the release means interact with the at least one molded part provided with the mold cavity in such a way that the casting channels are formed by placing the at least one molded part onto the release means. Alternatively, the casting channels can be incorporated into the release means, i.e., the at least one molded part with which the release means interact is not provided with casting channels. The release means are designed such that the casting channels provided by the release means open into the mold cavity formed by placing the at least one molded part onto the release means.

[0013] The press equipped with release agents facilitates the easy removal of the molded part with sprues, as the contact side of the molded part below the sprues does not have to be removed during the removal process. Due to the hardened mold material remaining in the sprues after the molding process, removing the contact side below the sprues after the encapsulation process is considerably more difficult. By first removing the molded part with the mold cavity, e.g., the upper mold part, the encapsulated electronic components can then be removed before the release agents are withdrawn from the mold assembly.

[0014] Alternatively, the release means can be retracted from the mold assembly after the molded part with which the release means interact has been detached. Preferably, the release means are adjustable in a direction substantially perpendicular to the direction of relative adjustment of the pressing elements. In such an embodiment, the material from which the release means are made is selected such that the portion of the mold material that has hardened in the sprues (which is partially bonded to the surface of the release means) is retracted from the mold assembly by retracting the release means.

[0015] Alternatively, the release means can be adjustable in a direction corresponding to the direction of relative movement of the pressing elements. By providing release means that are adjustable in the same direction as the relative movement of the pressing elements, the mold material that has hardened in the sprues after the electronic components have been molded can be removed by breaking.

[0016] The present invention further provides an actuator set for converting a press for encapsulating electronic components mounted on a carrier into a press according to the present invention. As disclosed above, the actuator set comprises at least one actuator for driving the relative displacement of one of the pressing elements of the press, wherein the at least one actuator is configured to be arranged on one of the pressing elements and connected to an intelligent control system of the press. Such an actuator set enables the conversion of a prior art press with a single drive into an advanced press according to the invention. Such a retrofit unit makes it possible to convert standard presses into the advanced system according to the present invention at a limited cost.The actuator set also includes displacement sensors for detecting the relative displacement of the press elements at various locations. The displacement sensors are configured to be arranged on the press elements and connected to the intelligent control system of the press. The actuator set may further include an intelligent control program required to control the processing of information from the displacement sensors.

[0017] The present invention further provides a method for encapsulating electronic components mounted on a carrier with encapsulation material, comprising the processing steps: A) placing an electronic component for encapsulation on a mold part, B) moving at least two mold parts relative to one another with a closing force such that the electronic components for encapsulation are enclosed by at least one mold cavity and the carrier is clamped between the mold parts, C) exerting pressure on a liquid encapsulation material with at least one piston such that encapsulation material is forced towards the at least one mold cavity enclosing the electronic components, D) filling the mold cavity with encapsulation material, and E) at least partially curing the encapsulation material in the mold cavity,wherein the distribution of the pressure exerted on at least one of the molded parts during processing step D) is varied as a function of measured local displacements of the molded parts.

[0018] With regard to the relative adjustment of the at least two mold parts, it is noted that the term “relative adjustment” includes at least the adjustment of both mold parts towards each other and the adjustment of one of the mold parts towards the other mold part.

[0019] The distribution of the pressure exerted on at least one of the molded parts during processing steps D) and E) can be varied depending on measured local displacements of the molded parts. With this method, an active pressure distribution across one (or even both) molded parts is realized during at least part of the conveying path. The conveyance of the molding material causes a fluctuation in the loads exerted on the molded parts as well as a fluctuation in the distribution of the loads exerted on the molded part, with the effect of (limited) changes in the local relative positioning of the molded part. These (limited) changes in the local relative positioning of the molded part, in turn, result in (limited) inaccuracies in the dimensions of the molded product, improved process control, and a limited risk of damage to supports during the molding process.For further advantages of the method according to the present invention, reference is made to the advantages mentioned above with regard to the press according to the present invention, which are also referred to here with regard to the method according to the invention.

[0020] The distribution of the pressure exerted on at least one of the mold parts can be varied by individually controlling at least two, but preferably at least three, independently controllable actuators that interact with at least one of the mold parts. The plurality of controls enable the orientation of the mold part to be changed, and complete control of the orientation setting requires at least three controls. To control the orientation of a mold part, the distribution of the pressure exerted on at least one of the mold parts can be controlled at least partially by feedback of the measured local displacements of the mold parts. In addition, the distribution of the pressure exerted on at least one of the mold parts can be controlled at least partially by feedforward of at least one detected process variable. If, for example,If the filling pressure and filling curve develop along known patterns of fluctuations in the applied pressure and pressure distribution, an estimate can be made of the changes in the relative orientation of the molded parts for a passive situation in which the expected changes are not compensated. Based on these estimates of behavior, a pre-control can anticipate the expected changes in the relative orientation. For such a pre-control, the distribution of the pressure applied to at least one of the molded parts can be controlled, at least in part, by stored historical process information. Such a control can also adapt continuously, so that the control becomes a "self-learning" control system.

[0021] Furthermore, the encapsulation method according to the present invention may further comprise, prior to clamping the carrier between the mold parts in step B), the step of adjusting release means in a direction substantially perpendicular to the direction of relative displacement of the at least two mold parts (or alternatively in a direction corresponding thereto), such that the release means form part of the contact side of the at least one mold part provided with the at least one mold cavity, in order to clamp the carrier between the release means and the mold parts. It is noted that by using the release means, they reduce the effective clamping force of the mold part with which the release means cooperate. The method of the present invention may therefore further comprise a calibration step prior to clamping the carrier between the release means and the mold parts.Such a calibration step comprises the relative adjustment of the at least two mold parts towards each other with a clamping force such that the electronic components are enclosed by at least one mold cavity for encapsulation and the carrier is clamped between the mold parts. By including such a calibration step, a base pressure can be measured without using the release agents. The base measurement of the clamping force is performed by relative adjustment of the at least two mold parts towards each other. The clamping force measured while using the release agents is compared with the clamping force measured during the base measurement. The actual clamping force exerted on the carrier is corrected by independently controlling the actuators.

[0022] The present invention will be explained in more detail on the basis of the non-limiting exemplary embodiments shown in the following figures, in which: Fig. Figure 1 shows a schematic view of a press for encapsulating electronic components according to the present invention; Fig. Figure 2A shows a schematic side view of a pair of molded parts and a carrier with electronic components in a pre-encapsulation situation in which the molded parts are open; Fig. 2B a side view of the molded parts and the carrier with electronic components as in Fig. Figure 2A shows a situation before encapsulation in which the mold parts are closed; Fig. 2C a side view of the molded parts and the carrier with electronic components as in the Fig. 2A and Fig. Figure 2B shows a situation during encapsulation with closed mold parts according to the prior art; Fig. 2D a side view of the molded parts and the carrier with electronic components as in the Fig. 2A and Fig. Figure 2B shows a situation during closed-mold encapsulation according to the present invention; Fig. 2E a side view of molded parts and the carrier with electronic components with dimensions different from those in Fig. 2B, here also in a situation before encapsulation in which the mold parts are closed; Fig. 2F a side view of the molded parts and the carrier with electronic components as in Fig. Figure 2E shows a situation during closed-mold encapsulation according to the present invention; Fig. 3 shows a plan view of a molded part with a mold cavity partially filled with molding material; Fig. 4A shows a schematic side view of a pair of mold parts and a carrier with electronic components in a pre-encapsulation situation in which the mold parts are open; Fig. 4B a side view of the molded parts and the carrier with electronic components as in Fig. Figure 4A shows a situation before encapsulation in which the mold parts are closed; Fig. 5A shows a schematic side view of a pair of molded parts and a carrier with electronic components in a pre-encapsulation situation in which the molded parts are open; and Fig. 5B a side view of the molded parts and the carrier with electronic components as in Fig. 5A shown in a situation before encapsulation in which the mold parts are closed.

[0023] Fig. Figure 1 shows a press 1 for encapsulating electronic components, comprising a frame 2 holding two pressing elements 3, 4 that are adjustable relative to each other according to arrow P. The press 1 comprises a main drive cylinder 5, i.e., the first actuator, controlled by a fluid pump system 6. The pressing elements 3, 4 are suitable for supporting two cooperating molded parts (not shown in this figure). The press also includes two displacement sensors 7, 8 for detecting the relative displacement of the pressing elements 3, 4 at various locations on the pressing elements 3, 4 (here on the left and right sides of the pressing elements 3, 4). The displacement sensors 7, 8 are connected to an intelligent controller 9, which may be part of an operating console 10. The information provided by the displacement sensors 7, 8 is processed by the intelligent controller 9 and may result in regulation of the fluid pump system 6.In the present invention, two additional individually controllable press cylinders 11, 12, i.e., the second and third actuators, are provided, which are also supplied (controlled) by the fluid pump system 6 via a control line 13, but in such a way that their adjustment is controlled individually (i.e., independently of the main drive cylinder 5 and independently of each other). This provides the possibility of influencing the distribution of the pressure exerted on the lower press element 4 (the pressure load) and thus the alignment of the lower press element 4.

[0024] Fig. Figure 2A shows a schematic side view of a pair of mold parts 20, 21. The upper mold part 21 is provided with a mold cavity 22, which is recessed in a contact side 23 of the mold part 21 for enclosing at least electronic components 24 placed on a carrier 25. Furthermore, a supply channel 26 for supplying mold material (not visible in this figure) into the mold cavity 22 is recessed in the upper mold part 21. The mold cavity 22 is surrounded by the contact side 23, which is designed to fit onto the carrier 25, and a vent opening 27 is provided in this contact side 23 to allow gases to escape from the mold cavity 22 during the molding process. The mold parts 20, 21 are formed as in Fig. 2B shown according to arrow P 2 placed on top of each other.

[0025] In Fig. 2B, the mold closure is carried out by the upper mold part 21 contacting the carrier 25 on the lower mold part 20, but this occurs before the molding material is fed into the mold cavity 22. The vent opening 27 leaves a small gas outlet between the carrier 25 and the mold part 21. Now that the mold parts 20, 21 are closed to avoid damage to the carrier 25 with limited clamping force of the press carrying the mold parts 20, 21, the situation is created to vent the mold cavity 22 via the sprue 26 according to P 3 to be filled with molding material.

[0026] In Fig. 2C, according to the prior art, molding material 28 is fed into the mold cavity 22. Here, the (in this Fig. 2C exaggerated) that the mold material 28 locally (here on the left side) exerts a pressure (see arrow P 4 ) on the upper mold part 21, this local pressure (P 4) causes the upper mold part 21 to become tilted (adjustment relative to the lower mold part 20). The disadvantages of such a relative adjustment of the mold parts 20, 21 include, among other things, that the resulting molded electronic component has an undesired shape (here a housing "package" made of the mold material 28 with a remaining slope) and that mold material 28 can escape between the contact side 23 of the mold part 21 and the carrier (see escape / bleeding / burr 30). A further disadvantage of the Fig. 2C is that the upper mold part 21 is pressed locally (see right side of the drawing) into the support 25, which could damage the support 25 and also affect the gas discharge capacity of the vent opening 27 (or even lead to a complete blockage of the gas discharge).

[0027] In Fig. 2D, molding material 28 is also fed into the mold cavity 22, but now in a situation according to the present invention. The upper mold part 21 is attached to a pressing element 31, which is actuated by two individually controllable actuators 32, 33 (here spindle actuators as an alternative to the Fig. 1 shown cylinder actuators). In order to reduce the pressure exerted by the mold material 28 (see arrow P 4 ), the pressure exerted by the left actuator 32 (see arrow P 5 ) is greater than the pressure exerted by the right actuator 33 (see arrow P 6 ). The different pressure distribution according to the present invention during the supply of the molding material 28 by the actuators 32, 33 prevents various Fig. 2C, the dimensions of the molded electronic components 24 are better controlled, there is less risk of damage to the carrier 25 and the venting 27 functions properly.

[0028] Fig. Figure 2E shows the mold parts 20, 21 clamping a carrier 25 with electronic components 24, with the electronic components 24 just touching the inside of the mold cavity 22 of the upper mold part 21 with high precision. In the illustrated situation, the mold parts 20, 21 are closed with limited clamping force to avoid damage to the carrier 25 and the electronic components 24.

[0029] In Fig. 2F, according to the present invention, molding material 28 is inserted into the electronic components as shown in Fig. 2E shown. The top of the electronic components 24 is kept free of mold material 28, such that after the molding process, "exposed" electronic components 24 remain. The upper mold part 21 is attached to the pressing element 31, as shown in Fig. 2D and, as already mentioned in relation to Fig. 2D, is driven by the two individually controllable actuators 32, 33. Here, too, the pressure exerted by the mold material 28 (see arrow P 4 ) via the pressure exerted by the left actuator 32 (see arrow P 5 ) which is greater than the pressure exerted by the right actuator 33 (see arrow P 6). The dimensions and exposed surfaces of the molded-in electronic components 24 are well controlled, there is limited risk of damage to the carrier 25 or the electronic components 24, and the venting 27 functions properly.

[0030] Fig. Figure 3 shows a top view of a molded part 40 with a mold cavity 41 partially filled with molding material 42. The (liquid) molding material 42 is fed into the mold cavity 41 by a piston 43. The mold cavity 41 shown here is circular, e.g., for molding a carrier in the form of a wafer. In addition, the locations where three individually controllable actuators 44, 45, 46 are located on the side of the molded part 40 opposite the side on which the mold cavity 41 is located are indicated by dashed lines. The positions of the individually controllable actuators 44, 45, 46 make it possible to control the complete orientation of the molded part 40, since three actuators 44, 45, 46 enable a complete adjustment of a surface (of the molded part 40) in the second dimension (alongside and across the flow direction of the molding material 42).

[0031] Fig. 4A and Fig. 4B show another embodiment of the present invention. Fig. Figure 4A shows a schematic side view of a pair of mold parts 20, 21. The upper mold part 21 is provided with a mold cavity 22 for enclosing at least electronic components 24 placed on a carrier 25. Furthermore, a supply channel 26 for supplying mold material (not visible in this figure) into the mold cavity 22 is recessed in the upper mold part 21. In contrast to the Fig. 2A, the molding device comprises the Fig. 4A further comprises release means 47 for the upper mold part 21 to facilitate the detachment of the upper mold part 21 from the encapsulated electronic components 24. The release means 47 are arranged according to arrow P 7 The release means 47 can be adjusted independently of the adjustment of the mold parts 20, 21. Similar to the Fig. 2A, the molded parts 20, 21 are moved according to arrow P 2Finally, by closing the mold parts 20, 21, but preferably before closing the mold parts 20, 21, the release means 47 are aligned with the mold parts 20, 21 in order to ensure the closed mold part arrangement of the Fig. 4B to form.

[0032] In Fig. 4B, the mold cavity 22 is as in Fig. 2B, surrounded by the contact side 23, which is partially formed by the release means 47, wherein the contact side 23 is adapted to fit onto the carrier 25, and a vent opening 27 is provided in this contact side 23 to allow gases to escape from the mold cavity 22 during the molding process. Furthermore, the mold closure is carried out by the upper mold part 21 contacting the carrier 25 and the release means 47 on the lower mold part 20, but this before the molding material is fed into the mold cavity 22. The vent opening 27 leaves a small gas outlet between the carrier 25 and the mold part 21. Now that the mold parts 20, 21 are closed to avoid damage to the support 25 with limited clamping force of the press carrying the mold parts 20, 21, the situation is created to fill the mold cavity 22 via the sprue 26 according to P 3 to be filled with molding material.

[0033] After filling the mold cavity 22 with molding material, the upper mold part 21 can be easily detached. By providing the release means 47 in the part of the contact side 23 in which the sprue 26 is provided, the upper mold part 21 can be detached without having to completely detach the surrounding contact side 23 from the carrier 25 on the lower mold part 20. After the upper mold part 21 is removed, the release means 47 are moved from the closed position (the Fig. 4B) to allow further detachment of the encapsulated electronic components 24. The separating means 47 are preferably retracted in a direction opposite to the direction defined by the Fig. 4A shown arrow P 7is opposite to the direction indicated. The material used for the release means 47 is preferably selected such that the part of the molding material 28 that has hardened in the casting channel 26 is withdrawn from the molding device by retracting the release means 47.

[0034] Similar to the Fig. 4A and Fig. The embodiments shown in Figure 4B show the Fig. 5A and Fig. 5B shows an embodiment comprising the release means 47, wherein the sprue 26 is provided in the release means 47. By closing the mold parts 20, 21, the formed mold cavity 22 is connected to the sprue 26 of the release means 47.

Claims

A press for encapsulating electronic components mounted on a carrier, comprising: - at least two pressing elements that are adjustable relative to one another in a pressure direction toward or away from one another for holding at least two cooperating mold parts, - a drive system for driving the relative adjustment of the at least two pressing elements, - a plurality of adjustment sensors for detecting the relative pressure direction of the pressing elements in the pressure direction of the at least two pressing elements at different locations of the at least two pressing elements, and - an intelligent controller connected to the drive system, wherein the intelligent controller is configured to control the drive system, wherein at least one of the at least two mold parts is provided with at least one mold cavity,which is recessed in a contact side to enclose at least one electronic component placed on the carrier, and the contact surface of this at least one molded part at least partially encloses the mold cavity in order to fit media-tight onto the carrier in a closed position of the molded parts, wherein the drive system comprises a plurality of individually controllable actuators in order to exert forces in the pressure direction of the at least two pressing elements at a plurality of locations, and wherein the intelligent controller is further connected to the plurality of adjustment sensors, wherein the intelligent controller is configured to dynamically control the actuators of the drive system over time based on the adjustment measured values ​​detected by the adjustment sensors in order to adjust the adjustment measured values ​​by changing the pressure distribution during the feeding of molding material into the mold cavity,with the mold parts in a closed position and the pressing elements exerting pressure on each other. Press according to claim 1, wherein the drive system comprises at least three individually controllable actuators. Press according to claim 1 or 2, wherein the direction of the pressure exerted by the actuators corresponds to the adjustment direction of the actuators. Press according to one of the preceding claims, wherein the individually controllable actuators are pressure cylinders. Press according to claim 4, wherein at least three pressure cylinders cooperate with a single pressing element. Press according to one of the preceding claims, wherein the adjustment sensors have a sensitivity for relative adjustments in the micrometer range. Press according to one of the preceding claims, wherein the adjustment sensors are arranged to detect objects which are not provided where they are detected. Press according to one of the preceding claims, wherein the pressing elements hold at least two mold parts, wherein at least one of the mold parts is provided with at least one mold cavity which is recessed in a contact side for enclosing at least one electronic component placed on the carrier, wherein the contact surface of this mold part at least partially encloses the mold cavity in order to fit onto the carrier in a media-tight manner. Press according to claim 8, wherein the press with mold parts also comprises feed means provided with at least one piston for exerting pressure on a liquid encapsulating material such that the encapsulating material is forced towards the mold cavity enclosing the electronic component. Press according to claim 8 or 9, wherein the press further comprises release means to facilitate the detachment of the at least one molded part, which is provided with at least one mold cavity recessed in a contact side for enclosing at least one electronic component placed on the carrier, wherein the contact side is formed by the contact surface of the release means and the contact surface of the at least one molded part with which the release means cooperate. Press according to claim 10, wherein the separating means are adjustable in a direction substantially perpendicular to the direction of relative adjustment of the pressing elements. Press according to claim 10 or 11, wherein the separating means comprise a feed channel for feeding encapsulating material into the mold cavity. A method for encapsulating electronic components mounted on a carrier with encapsulation material using a press according to one of claims 1 to 12, comprising the processing steps: A) Placing an electronic component for encapsulation on a mold part, B) Relatively adjusting the at least two mold parts towards each other with a closing force such that the electronic components are enclosed for encapsulation in the at least one mold cavity and the carrier is clamped between the mold parts, C) Exerting pressure on a liquid encapsulation material with at least one piston such that encapsulation material is forced towards the at least one mold cavity enclosing the electronic components, D) Filling the mold cavity with encapsulation material, and E) At least partially curing the encapsulation material in the mold cavity,wherein the distribution of the pressure exerted on at least one of the molded parts during processing step D) is varied as a function of measured local displacements of the molded parts by carrying out the following steps D-1) and D-2):D-1) measuring relative displacements by means of the displacement sensors at different locations on the molded parts andD-2) changing the pressure distribution exerted on at least one of the molded parts in order to reduce the measured local displacements of the molded parts. A method for encapsulating according to claim 13, wherein the distribution of the pressure exerted on at least one of the molded parts is varied at least during processing steps D) and E). A method of encapsulation according to claim 13 or 14, wherein the distribution of the pressure exerted on at least one of the mold parts is varied by individually controlling at least two independently controllable actuators which cooperate with at least one of the mold parts. A method of encapsulation according to any one of claims 13 to 15, wherein the distribution of the pressure exerted on at least one of the mold parts is controlled at least partially by feedback of the measured local displacements of the mold parts. A method of encapsulation according to any one of claims 13 to 16, wherein the distribution of the pressure exerted on at least one of the molded parts is controlled at least partially by feedforward coupling of at least one sensed process variable. A method of encapsulating according to any one of claims 13 to 17, wherein the distribution of the pressure exerted on at least one of the mold parts is controlled at least in part by stored historical process information. A method for encapsulation according to any one of claims 13 to 18, wherein prior to clamping the carrier between the mold parts in step B), the method further comprises the step of adjusting release means in a direction substantially perpendicular to the direction of relative adjustment of the at least two mold parts, such that the release means form part of the contact side of the at least one mold part provided with the at least one mold cavity, in order to clamp the carrier between the release means and the mold parts. A method for encapsulation according to any one of claims 19, wherein, prior to clamping the carrier between the release means and the mold parts, the method further comprises a calibration step which includes a relative adjustment of the at least two mold parts towards one another with a closing force such that the electronic components are enclosed by at least one mold cavity for encapsulation and the carrier is clamped between the mold parts.

Images