Field of the invention

The present invention relates to a mould for an integrated circuit package. In a further aspect, the present invention relates to a method for providing an integrated circuit package using a film assisted moulding technique.

Prior art

German patent publication DE-A-10 2011 004381 discloses an integrated circuit package moulding method using spring-loaded metal elements. An integrated circuit package is manufactured by providing a bottom part and a top part on each side of a circuit board, wherein in the top part a portion is held free from a moulding compound using metal barriers which are spring loaded and held onto the circuit board around a sensor area on the circuit board.

International patent publication WOO 1/20644 discloses a method and apparatus for partially encapsulating a semiconductor chip. A substrate with the chip is placed on a first mold halve, a film is placed between the chip and a second mold halve. Then the film is pressed against the chip only at the circumference thereof, and encapsulating material is injected into the mold.

Summary of the invention

The present invention seeks to provide an improved method for providing an integrated circuit assembly ("a functional package") using film assisted moulding whereby compound flashing on sensitive and fragile sensor surfaces and/or cracking thereof is effectively prevented.

According to the present invention, a mould for providing an integrated circuit assembly according to the preamble defined above is provided, wherein the mould comprises a cavity block having an interior space for holding the integrated circuit assembly which interior space is filled with a moulding compound during operation to form the integrated circuit package, wherein the cavity block comprises one or more rigid elements moveable in a direction substantially perpendicular to a major surface of the interior space, and extending into the interior space, wherein the one or more rigid elements are held moveably in the cavity block using at least one resilient material element, wherein a renewable film is provided as a package wall extending over the major surface of the interior space and extending end parts of the one or more rigid elements, the renewable film being held under local pressured contact with the sensor surface by the one or more rigid elements during operation.

The mould according to the present invention provides a resilient engagement of the one more rigid elements with the at least one sensor surface, wherein the renewable film is disposed there between. The resilient engagement is achieved through the resilient material element which moves the one or more rigid elements into the interior space and limits a local pressure force onto fragile sensor surfaces to prevent damage thereof. In typical embodiments the renewable film exhibits some resiliency or elasticity also, thereby complementing the resiliency of the resilient material element and avoiding "hard" contact between the one or more movable rigid elements and the at least one sensor surface. In view of the present invention, the at least one sensor surface may comprise a protective lid element or cover made of e.g. plastic, glass and the like.

In many embodiments of the invention the one or more moveable rigid elements comprise a metal material, which material is relative easy to machine accurately and suitable to be used in a mould due to its durability.

Integrated circuit packages may comprise various sensors and sensor surfaces tailored to a specific application. As such, in versatile embodiments characteristics of the resilient material element (shape and dimensions) and dimensions of the one or more rigid elements (e.g. contact area of the rigid elements on the resilient element) are selected to apply a preset force to each of the one or more moveable rigid elements during operation. The preset force may be specifically adapted to particular sensor and sensor surfaces to minimize compound bleed yet avoiding damaging fragile sensor surfaces.

In an embodiment, the resilient material element may comprise a heat resistant material, such as silicone, synthetic rubber, fluoroelastomer types. This embodiment ensures that with high temperatures of moulding compound in the mould during a moulding cycle, the resilient material element retains its requires elasticity and compliance.

In a typical embodiment, the resilient material element comprises a sheet of material in contact with the one or more moveable rigid elements. In this particular configuration the one or more movable rigid elements are in engagement with a common resilient material element so that a common preset force is applied to the at least one sensor surface. This is advantageous in case integrated circuit packages are to be provided with identical sensors.

Sometimes a row wise arrangement of identical sensors is required, and so in an embodiment the resilient material element may comprises a plurality of elongate strips of resilient material, wherein each elongate strip is in contact with a subgroup of the one or more moveable rigid elements. In this way a row of sensors can be subjected to equal resilient pressure forces imposed by the subgroup of rigid elements that are in engagement with a resilient material strip.

For maximum control of pressure forces imposed on each sensor to be provided in the integrated circuit package, the resilient material element may comprise a plurality of resilient form pieces, each being attached to one of the one or more moveable rigid elements. In this way each sensor is subjected to a specific pressure force during a moulding cycle, which may be advantageous in case the integrated circuit package is to be provided with many different sensors, e.g. different sensor types having different fragile sensor surfaces.

As mentioned above, the renewable film offers a level of resiliency and elasticity as well when in contact with the at least one sensor surface. According to the present invention the renewable film also minimizes compound bleed during a moulding cycle by providing adequate sealing. For good sealing properties, in an embodiment the renewable film may comprise a sealing material, such as PTFE or polyester.

Sensors and sensor surfaces thereof embedded in an integrated circuit package need not always be oriented substantially parallel a flat integrated circuit package. For example, in certain applications it is required that a sensor surface is disposed at an angle with respect to an integrated circuit package. To that end the one or more moveable rigid elements may comprise a sensor contacting surface disposed at an angle with respect to a longitudinal direction of the one or more the rigid elements. This allows such an angled sensor surface to be engaged by a parallel contacting surface of a rigid element, wherein the rigid element is movably disposed substantially

perpendicular to e.g. a flat integrated circuit package.

In a further aspect, the present invention relates to an improved method for providing an integrated circuit package using a film assisted moulding technique, which is particularly advantageous for packaging fragile sensors. The method comprises providing an integrated circuit assembly with at least one sensor surface and providing an interior space around the integrated circuit assembly using a mould, wherein the mould comprises a resilient material element exerting a force on one or more moveable rigid elements extending into the interior space at a position corresponding to the at least one sensor surface. The method further comprises applying a renewable film over extending ends of the one or more moveable rigid elements, and closing the mould such that the renewable film is held in pressured contact with the at least one sensor surface over a surface area corresponding to the extending ends of the one or more rigid elements, and filling the interior space with moulding compound.

As with the mould described above, the method of the present invention has the advantage in that it provides a resilient engagement of the one more rigid elements with the at least one sensor surface, wherein the renewable film is disposed there between. The resilient engagement is achieved through the resilient material element which moves the one or more rigid elements into the interior space and limits a local pressure force onto fragile sensor surfaces to prevent damage thereof.

In an embodiment, the pressure exerted by each of the one or more moveable rigid elements is individually controlled. This allows maximum control for each sensor surface to be engaged by a rigid element, and so this allows integrated circuit packages to be manufactured having differently sensors and sensor surfaces having varying characteristics.

In an embodiment, the one or more moveable rigid elements may have a cross section of 1 mm ² or less, e.g. having a diameter of 400μπι in case of a circular cross section. In another embodiment, the one or more moveable rigid elements may have a cross section of more than 1 mm ² , e.g.100 mm ² . Hence, according to the invention a large range of sensor sizes and sensor surfaces can be handled, thereby providing a integrated circuit packaging solution for a many types of applications.

Note that the one or more movable rigid elements may have e.g. circular, rectangular, square, or polygon cross sections for facilitating embedding various sensor geometries. However, in case the above mentioned cross section cannot be used, then according to the present invention the method may further comprise adapting a size or shape of the one or more moveable rigid element to the at least one sensor surface. In particular, extending ends of the one or more moveable elements may likewise be adapted to meet requirements in regard of specific sensor geometries.

Short description of drawings

The present invention will be discussed in more detail below, using a number of exemplary embodiments, with reference to the attached drawings, in which

Figure 1 shows a cross sectional view of an embodiment of a cavity block according to the present invention;

Figure 2 shows an exploded, partial view of an embodiment of an array of moveable rigid elements according to the present invention, similar to the embodiment of Figure 1;

Figure 3 shows a perspective view of the embodiment of a cavity block of Figure 2;

Figure 4 shows a partial cross sectional view of an embodiment of a moveable rigid element according to the present invention;

Figure 5 shows a cross sectional view of an integrated circuit assembly in engagement with a renewable film according to an embodiment of the present invention;

Figure 6a shows an embodiment of a plurality of movable rigid elements each having a separate resilient material element according to the present invention;

Figure 6b shows an embodiment of a plurality of moveable rigid elements provided with a common resilient material element according to the present invention; and

Figure 7 shows an embodiment of a leaded integrated circuit package according to the present invention.

Detailed description of exemplary embodiments

Current technological developments often require smaller functional packaging solutions for integrated circuits, such as sensor packaging and encapsulation wherein an exposed sensor area or surface should be minimized. In contrast to miniaturization into Thin-Thin micro-QFN, -LGA or -BGA types, there is also increased demand for e.g. optical and sensitive areas in both leadless and leaded functional packages. There is a need for a robust and mature moulding technology capable of controlled shielding of fragile sensor surfaces during encapsulation of a sensor by e.g. a moulding compound, for a wide range of sensitive areas, from very small areas, e.g. 400μιη diameter, to large areas, (e.g. up to 120 mm ² ). The moulding technology should keep exposed sensor surfaces clean and should compensate for thickness variations, particularly for integrated circuit assemblies comprising a stacked die or glass on die.

The present invention provides a solution for the above need by utilizing a combination of Film (Foil) Assist Moulding (FAM) and compressible movable elements, thereby sealingly covering each individual sensitive sensor surface under a foil without damaging sensitive and fragile sensor surfaces. Another advantage of the present invention is that compound flashing is further minimized.

Figure 1 shows an embodiment of a mould according to the present invention, wherein the mould 1 comprises a cavity block (2, 2a) having an interior space 3 for holding an integrated circuit assembly 8-11 with at least one sensor surface as shown for example in Figure 5.

Figure 5 shows a typical example of an integrated circuit package 8-11 as provided using the present invention embodiments. A chip die or integrated circuit 8 is provided with a sensor/sensor surface 9 and attached to a lead frame 10 (or other type of support frame). The mould material 11 forming the integrated circuit package after moulding enclosed the chip die 8, lead frame 10 and e.g. bond wires 13. In the embodiment shown, the sensor surface 9 is also protected by a lid element (e.g. plastic, glass) on die 14, which is attached to the chip die 8 and sensor surface 9, resulting in a stack height h. For ease of reference, in some embodiments the sensor surface 9 may be construed as comprising the protective lid element.

When the mould 1 is in operation, the interior space 3 is filled with a moulding compound to form the integrated circuit package 8-11. In an embodiment the moulding compound may be a thermoset or a therm oharder material. The cavity block 2, 2a comprises one or more rigid elements 5 moveable in a direction substantially perpendicular to a major surface of the interior space 3 and extending into the interior space 3.

The mould 1 further comprises at least one resilient (e.g. flexible, pliable) material element 4, wherein the one or more rigid elements 5 are held moveably in the cavity block 2 using the at least one resilient material element 4. The at least one resilient material element 4 is arranged for resilient and compressible engagement of the one or more rigid elements 5 with the integrated circuit assembly 8-11 during a moulding process without breaking any sensitive sensor surfaces of said assembly 8-11, e.g. using a closing block 7 which is adapted to fit into the opening in the cavity block 2.

In an exemplary embodiment, each rigid element 5 may be envisaged as a command pin 5 movably disposed in the cavity block 2,2a.

According to the invention, the mould 1 is further provided with a renewable film 15 functioning as a package wall extending over the major surface of the interior space 3 and extending end parts of the one or more elements 5. The renewable film 15 is held under local pressured contact with the sensor surface by the one or more elements 5 during operation. As shown, the interior space 3 may be embodied as a recess 3 wherein the renewable film 15 covers said recess 3 and defines a package wall of the integrated circuit assembly 8-11 when the recess 3 is being filled with a moulding compound. In advantageous embodiments, the interior space 3 may be provided with angled surfaces or tapered surfaces to facilitate releasing a finished integrated circuit assembly 8-10.

In a typical embodiment, each rigid element 5 may protrude or extend into the interior space 3, wherein the renewable film 15 covers each protruding/extending end part of each rigid element 5. Such a protruding or extending end part produces a recess in the package material of the integrated circuit assembly 8-11 during an encapsulation cycle, wherein the at least one sensor surface is in direct contact with the renewable film 15 under pressure of an end part of the rigid element 5. This prevents

encapsulation of sensor surfaces during encapsulation. Alternatively the rigid element 5 may be equal or below the interior space 3 level.

In many embodiments the renewable film 15 will be resilient or compressible under localized pressure of an extending end part of a rigid element 5, thereby further avoiding any damage to fragile and sensitive sensor surfaces while applying pressure thereon. Typically the compressibility of the renewable film 15 is less than the compressibility of the at least one resilient material element 4. Characteristics of the at least one resilient material element 4 and dimensions of the one or more rigid elements 5 are selected to apply a preset force to each of the one or more moveable rigid elements 5 during operation. In this way a very accurate and localized pressure can be applied to each sensor surface without breaking or damaging said sensor surface.

In an embodiment, the renewable film 15 is slidably arranged along the cavity block 2, 2a for obtaining a clean interface surface between the renewable film 15 and a sensor surface of the integrated circuit assembly 8-11 during each moulding and encapsulation cycle. Advantageously, the renewable film 15 may comprise a sealing material, such as PTFE or polyester for improved sliding, compression and sealing characteristics.

The one or more rigid elements 5 are arranged for being moved by the at least one resilient material element 4 for engaging and disengaging the extending end part of each rigid element 5 with or from a sensor surface. The renewable film 15 is disposed between each rigid element 5 and an associated sensor surface thereof. Each of the rigid elements 5 (e.g. in the form of command pins 5) may be individually movable, so that a tailored, local preset pressure force may be provided for each individual and separate sensor surface 9 (which may be covered by a glass on die 14).

In an exemplary embodiment, the one or more moveable rigid elements 5 comprises a metal material. For example, each of the one or more moveable rigid elements 5 may be envisaged as a metallic command pin 5 slidably disposed in the cavity block 2, 2a. Each moveable rigid element 5 may also comprise a predefined cross sectional form, e.g. a rectangular, round or hexagonal cross section, depending on the sensor surface 9 to be held free from encapsulation compound. Furthermore, each movable rigid element 5 may even be specifically adapted to the sensor surface 9 for certain applications. For example, each of the one or more moveable rigid elements 5 is in engagement with the at least one sensor/sensor surface 9 during a moulding cycle. Since the at least one sensor surface 9 may be disposed at an angle with respect to a the integrated circuit package, extending ends of the one or more moveable rigid elements 5 may comprise a sensor contacting surface disposed at an angle with respect to a longitudinal direction of the one or more the rigid elements 5, so that it is parallel to the at least one sensor surface 9. In the embodiments shown in Figure 1 and 5, the mould 1 of the present invention allows one or more sensor surfaces 9 and/or a glass on die 14 on top of the sensor/sensor surface 9 (effectively forming a stack of integrated circuit components with height h) to be sealingly covered by the thin renewable film 15. When engaged with the one or more sensor surfaces 9 and/or the glass on die 14, the renewable film 15 is adapted to prevent compound flashing between the renewable film 15 and the one or more sensor surfaces 9 and/or the glass on die 14 during an encapsulation cycle.

According to the invention, the renewable film 15, the one or more rigid elements 5, and the at least one resilient material element 4 are arranged to provide a soft, snug and uniform compressible fit of the renewable film 15 against fragile sensor surfaces 9 and/or glass on die 14, thereby preventing damaging the sensor surfaces 9 and/or glass on die 14. In typical embodiments the renewable film 15 is sufficiently flexible and strong to provide a tight and sharp transition 12 between package compound 11 and a sensor surface 9 and/or glass on die 14, thereby reducing compound flashing.

The resilient material element 4 of the present invention may be referred to as a "soft piece" or a "soft touch" that is specifically adapted to allow the one or more rigid elements 5 to follow protruding contours and varying thicknesses of one or more sensors 9 and/or glass on die 14 when engaged therewith.

In an embodiment, the resilient material element 4 may comprise a heat resistant or retardant material such as silicone, synthetic rubber and/or fluoroelastomer types. This ensures that the resilient material element 4 is compressible, pliable and able to handle high temperatures of e.g. rigid elements 5 and the cavity block 2, 2a when a (viscous) moulding compound is present the interior space 3.

Typically, the resilient material element 4 may comprise a sheet of material in contact with a plurality (e.g. array) of moveable rigid elements 5. This sheet of material may be envisaged as a pliable, compressible sheet configured for providing a resilient engagement of the one or more rigid elements 5 with the one or more sensors 9 and/or glass on die 14 during a moulding cycle. According to the invention, the renewable film 15 interposed between the one or more rigid elements 5 and the one or more sensors 9, and/or glass on die 14, is able to adopt its shape for sealingly covering said sensors 9 and/or glass on die 14. That is, the renewable film 15 is in snug engagement with one or more sensor surfaces during a moulding cycle, so that compound flashing between the renewable film 15 and the one or more sensor surfaces is minimized.

Figure 2 shows a partially exploded view of the embodiment shown in Figure 1 of the cavity block 2 provided with a resilient material element 4 and one or more moveable rigid elements 5 according to the present invention. In this embodiment the one or more rigid elements 5 may be viewed as one or more rigid, slidably disposed command pins 5 extending through the cavity block 2 and engaging the resilient material element 4. In the embodiment shown, the one or more rigid elements 5 are arranged in a regular array and may protrude from the cavity block 2.

Figure 3 shows a perspective and exploded view of the embodiment of Figure 1.

This embodiment shows a cavity block 2, 2a, the one or more movable rigid elements 5, the at least one resilient material element 4 and the associated closing block 7. As an alternative, the closing block 7 could be implemented as an actuator 7 configured for exerting (localized) pressure onto the at least one resilient element 4. In this

embodiment the resilient material element 4 is a sheet of pliable and resilient material configured for resiliently engaging the one or more rigid elements 5 (e.g. command pins 5). This allows for compressible engagement of the one or more rigid elements 5 and renewable film 15 with sensitive and fragile sensor surfaces of an integrated circuit assembly 8-11 during an encapsulation cycle.

A detailed cross section of an embodiment of a movable rigid element 5 and the at least one resilient material element 4 is depicted in Figure 4. In this embodiment each rigid element 5 may be envisaged as a command pin 5 slidably disposed in the cavity block 2 and engaging a spherically shaped resilient material element 4, which is interposed between the command pin 5 and plurality of closing blocks 7 (e.g. in the form of metal strips provided in the cavity block 2). The closing blocks 7 are held in place using a cover 2' of the cavity block 2 The advantage of this particular

embodiment is that a row of sensors/sensor surfaces 9 can be sealingly covered by the renewable film 15 under a local pressure force that is specifically adapted and tailored to each row of sensors/sensor surfaces 9.

In the alternative embodiment shown in Figure 4, the resilient material element

4 thus comprises a plurality of elongate strips of material, wherein each elongate strip is in contact with a subgroup (e.g. two or more) of the one or more moveable rigid elements 5. In alternative embodiments, the resilient material element 4 may also comprise a plurality of rectangular or square pads of resilient material, each pad of resilient material being in contact with a subgroup (e.g. two or more) of the one or more moveable rigid elements 5.

Instead of having a spherically shaped resilient material element 4 associated with a single rigid element 5 as depicted in Figure 4, the resilient material element 4 may also be envisaged as a resilient material strip 4 in engagement with a subgroup (e.g. a row) of one or more rigid elements 5. The resilient material strip 4 may also be actuated by an actuator 7 disposed in the cavity block 2, 2a. This embodiment is particularly advantageous for row wise arrangements of identical sensors/sensor surfaces 9, wherein each sensor/sensor surface 9 in the same row is to be subjected to a substantially identical local pressure forces during a moulding cycle.

Figure 6a shows an embodiment of a cavity block 2 and the one or more rigid elements 5. In this embodiment the at least one resilient material element 4 comprises a plurality (array) of form pieces 4, each attached to one of the one or more moveable rigid elements 5. Put differently, each of the one or more moveable rigid elements 5 is in engagement with at most one of the plurality of form pieces 4. This is particularly advantageous as it allows each sensor/sensor surface 9 to be engaged by an associated command pin 5 imposing an individually adapted local pressure force. Such an embodiment may be desirable should the integrated circuit assembly 8-11 comprise a plurality of different sensors/sensor surfaces 9 each having different specifications.

Figure 6b show an embodiment of a plurality of moveable rigid elements 5 provided with a common resilient material element 4. As shown, in this embodiment a plurality of rigid elements 5 may be provided with a common resilient material element 4, such as a rectangular pad of resilient material 4 in engagement with the plurality of rigid elements 5. In this embodiment, because of the common resilient material element 4 each of the plurality of rigid elements 5 imposes an equal force on each sensor/sensor surface 9.

Figure 7 depicts an embodiment of a mould 1 and an integrated circuit package disposed therein according to the present invention. In this embodiment an interior space 3 is provided comprising an upper interior space 3a and a lower interior space 3b disposed around the integrated circuit assembly with the at least one sensor/sensor surface 9, a lead frame 10 and a plurality of bond or lead wires 13. The upper and lower interior spaces 3a, 3b allow for a double-sided encapsulation. As with previous embodiments, the renewable film 15 is in engagement with the one or more moveable rigid elements 5 that define apertures to be formed in the package compound during the moulding process. The resilient material element 4 engages the one or more rigid elements 5 for providing a resilient engagement of the renewable film 15 with the at least one sensor/sensor surface 9 and to prevent damage thereof. To briefly summarize the above, according to the present invention there are various embodiments of the resilient material element 4. In a first embodiment the resilient material element 4 may comprise a single pliable sheet of material. This single sheet of resilient material 4 is in engagement with the one or more moveable rigid elements 5 (e.g. command pins 5).

In a second embodiment, the resilient material element 4 comprises a plurality of resilient material strips/plates, rectangular or square pads 4, each in engagement with a subgroup (e.g. two or more) of movable rigid elements 5 (e.g. command pins 5). This embodiment is advantageous for e.g. row wise arrangement of a plurality of sensors 9, wherein all sensors 9 in a row are covered by a row wise arrangement of one or more rigid elements 5 that impose substantially equal pressure forces on each sensor 9 in such a row.

In a third embodiment, the resilient material element 4 comprises a plurality of resilient form pieces 4, e.g. resilient soft touch pads 4, wherein each form piece 4 is attached to one of the one or more moveable rigid elements 5, e.g. command pins 5. In this embodiment each sensor 9 and/or glass on die 14 can be individually covered with an individually adapted pressure force imposed by an associated rigid element 5.

In each of the above embodiments a moveable renewable film 15 may be provided interposed between the one or more sensors 9, and/or glass on die 14, and the one or more rigid elements 5. The renewable film 15 provides a clean and clear surface for engagement with one or more fragile sensors 9 and/or glass on die 14 during each moulding cycle. That is, the renewable film 15 is renewed every time a new sensor 9 is to be encapsulated in an integrated circuit package 8-11. In a typical embodiment, the renewable film 15 is provided by an actuated roll, which linearly moves the renewable film 15 along the cavity block 2, 2a as shown in Figure 1. As in all other embodiments, the resilient renewable film 15 of the present invention prevents flashing of moulding compound between one or more sensor 9 surfaces and the renewable film 15.

According to the invention, the one or more moveable rigid elements 5, the resilient material element 4, as well as the renewable film 15 need not be disposed at one particular side of the mould 1 as depicted in the embodiments shown in e.g. Figure 1 and Figure 5. It is therefore conceivable that the one or more moveable rigid elements 5, the resilient material element 4, as well as the renewable film 15 may be disposed at both sides of the mould 1 for e.g. double sided integrated circuit packages. In a further aspect, the present invention relates to a method for providing an integrated circuit package 8-11 using a film assisted moulding (FAM) technique. Hereinafter reference is made to all previously presented Figures 1 to 6.

According to the invention, the method comprises providing an integrated circuit assembly 8-11 with at least one sensor surface 9 and providing an interior space 3 around the integrated circuit assembly 8-11 using a mould 1. The interior space 3 may be provided using a cavity block 2, 2a having cavity (e.g. recess) defining the interior space 3. The encapsulation process of a sensor 9 takes place at least partially inside the interior space 3. The mould 1 comprises a resilient material element 4 exerting a force on one or more moveable rigid elements 5 extending into the interior space 3 at a position corresponding to the at least one sensor surface 9.

The method further comprises applying a renewable film 15 over extending ends of the one or more moveable rigid elements 5, thereby ensuring that a clean surface of the renewable film 15 is applied for preventing possible damage to the at least one sensor surface 9. For example, damage done by dust and various abrasive particles on the renewable film 15 is prevented by continuously renewing the film 15 for each packaging and moulding cycle.

The method then comprises closing the mould 1 such that the renewable film 15 is held in pressured contact with the at least one sensor surface 9 over a surface area corresponding to the extending ends of the one or more rigid elements 5. This ensures that the renewable film tightly fits over each extending end of the one or more rigid elements 5 and sealingly covers the at least one sensor surface 9. This minimizes compound flashing ("bleed through") between the at least one sensor surface 9 and the renewable film 15.

Finally the method comprises filling the interior space 3 with a moulding compound.

According to the invention, the resilient material element 4 allows resilient and compressible engagement of the one or more rigid elements 5 and renewable film 15 with a predefined surface area of a sensor 9 and/or glass on die 14. In an embodiment, the pressure exerted by each of the one or more moveable rigid elements 5 may be individually controlled. This embodiment is particularly advantageous when the integrated circuit assembly 8-11 comprises a plurality of sensors 9 having different specifications, e.g. varying surface strength, fragility, resistance to cracks and so on. Individually controlling each moveable rigid element 5 enables an optimal localized force for each sensor surface, thereby minimizing surface cracks and flashing of package compound.

As with the mould 1 disclosed earlier, each of the one or more rigid elements 5 may be envisaged as a linearly movable command pin 5 having e.g. a rectangular, round or hexagonal cross section, wherein the command pin 5 comprises an extending end engaging a sensor surface 9 and/or glass on die 14. The one or more moveable rigid elements 5 may have a cross section of 1 mm ² or less, e.g. having a diameter of 400μιη. This embodiment is advantageous when small apertures in the package compound of an integrated circuit assembly 8-11 are required having e.g. a round, rectangular, or hexagonal shape. For example, this embodiment may be particularly advantageous for miniaturized assemblies 8-11 having one or more small sensors.

Conversely, applications requiring a large sensor, such as an optical sensor (sometimes provided with a glass on die 14), the one or more moveable rigid elements 5 may have a cross section of more than 100 mm ² .

As an alternative to rectangular, round or hexagonal cross sections of the one or more moveable rigid element 5, e.g. command pins5, the method may further comprise adapting a size or shape of the one or more moveable rigid element to the at least one sensor surface 9.

The present invention embodiments have been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.