TWI648140B - Mould, moulding press and method for encapsulating electronic components mounted on a carrier using micro-pillars - Google Patents

Abstract

The invention relates to a mold for packaging electronic components on a carrier, including at least The two model fittings are corresponding to each other and are movable to each other, and the corresponding contact sides are respectively clamped to each other to form at least one molding cavity surrounding the electronic component to be packaged, wherein at least one of the model fittings has a molding cavity And recessed on the contact side, wherein at least a portion of the surface of the contact side of the molding cavity recessed in the film-type fitting has an elastic micro-column. The invention also relates to a molding machine for encapsulating electronic components on a carrier, including the above-described mold. The invention further relates to a method of packaging an electronic component on a carrier, using an elastic microcolumn (preferably an elastic fiber microcolumn) to support at least a portion of the metal film in the molding cavity.

Description

a mold, a molding press for packaging electronic components on a carrier using a microcolumn method

The present invention relates to a mold for encapsulating an electronic component on a carrier, comprising at least two displaceable mold fittings which are mutually joined by respective contact sides to form at least one molding cavity surrounding the desired Packaged electronic components. The invention also relates to a molding machine for encapsulating electronic components on a carrier, and a packaging method for packaging electronic components on a carrier.

The use of packaging materials to encapsulate electronic components located on a carrier is a commonly used technique. In the process industry, electronic components of the above type are typically packaged using cured epoxy resins and other additive materials. In the current market trend, it tends to package a large number of small-sized electronic components at the same time. Small-sized electronic components such as semiconductors (wafers, LEDs) are becoming smaller in size. The packaging material used in the package is configured to package a large number of electronic components, and the package may be located on one side of the carrier or on both sides of the carrier for simultaneous packaging. The encapsulating material is typically in contact with the carrier in a flat layer pattern. The carrier may comprise a lead frame, a multilayer structure substrate, an epoxy processed article (commonly referred to as a carrier or a substrate, etc.), or other carrier structure.

In the process of encapsulation, it is common to use a molding machine having two halves of a corresponding shape, and at least one of the mold halves has one or more recessed cavities. The carrier on which the electronic component is mounted is placed between the two mold halves, and the two mold halves move closer to each other, or more, for example, the two mold halves are close to each other and sandwich the carrier. The liquid encapsulating material that has been heated by the general procedure is then filled into a mold cavity, such as by transfer moulding. Or, for example, a granular encapsulating material is fed into the molding cavity before the two halves are molded together, so that the electronic component can be molded into the encapsulating material; the pressing packaging method is transfer molding. Another implementation. Commonly used encapsulating materials are epoxy gums (or resins) and are often used with other additives. After at least a portion of the encapsulating material is (chemically) cured in the mold cavity, the carrier with the packaged electronic components is removed from the molding press. And the packaged electronic components are separated from each other before proceeding to the next step. In the packaging process, a metal film can be used to shield or cover portions of the electronic components to prevent portions of the electronic components from being covered by the encapsulating material while also shielding between the encapsulating material and the mold surface. Partially covered products (not covered by molded products, also known as "bare" or "exposed die" products) can be applied to a variety of products; such as many different sensing elements, ultra-thin packaging (ultra- Thin packages) or heat sink components. The above-described packaging method is used for a larger size product and provides a good packaging effect to the above-mentioned partially uncovered electronic components. However, as the size of the market products is also shrinking, the conventional technology cannot provide accurate size control for the packaged products in the packaging step and the subsequent processing steps of the packaged electronic components to meet the market requirements for precision.

Based on the above problems and needs, the present invention aims to provide an alternative method and apparatus that has the advantages of conventional packaging methods and provides a better and more accurate electronic component package.

To achieve the above object, the present invention provides a mold for encapsulating an electronic component on a carrier, comprising at least two model fittings movable to each other, the at least two model fittings being disposed to correspond to each other, for example, having corresponding contacts with each other The sides may be clamped or snapped to each other to form at least one molding cavity to surround the electronic component containing the package to be packaged, wherein at least one of the model fittings has a molding cavity embedded/recessed on the contact side of the model fitting; At least a portion of the surface of the contact side recessed in the cavity of the film-type fitting has elastic micro-pillars, preferably an elastic fiber micro-column (ie, a micro-pillar made of elastic fiber elastomer) ). At this level, the cavity formed on the contact side can be understood as a part of the contact side of the mold fitting, wherein the cavity is recessed. Due to the elastic/elastic properties of the microcolumns, the micropillars are present on the surface of a model fitting to compensate for the small height difference between the electronic components to be molded (at least a portion of which is surrounded by the encapsulating material). Microcolumns usually have a linear force-displacement curve, and their plastic deformation (compression and/or bending of the microcolumn configuration) can avoid the situation of large expansion of the microcolumn. . In particular, when the metal film is pressed against the electronic component so that part of the electronic component is not covered by the encapsulating material, the microcolumn can provide compensation for height difference in this case, but can compensate the electronic component on the carrier (crystal The height difference of the particles, wafers or other components is limited, and since some of the electronic components are not covered by the packaging material, contamination of the surface of the electronic components may occur during the packaging process. The above-mentioned method for preventing pollution can be a commonly known method of bleed-and-flash free moulding (or no-edge molding). According to the method of the prior art, the elastic metal film is used to improve the finite height difference, but due to the characteristics of the metal film, it may cause the connection of the electronic component and/or the electronic component to the carrier in the vertical direction (such as a flip chip connection). The guide posts or bumps in the wire have high pressure and stress, and also cause high stress in the interposer or the carrier, resulting in very limited flexibility of the metal film for highly adaptable properties. . High stress (high load) may cause cracking of the electronic component to be packaged, such as occurs between the electronic component and the environment (carrier) The intermediate connection portion, and/or on the electronic component mounting substrate or carrier, should avoid the above-mentioned high stress generation. When the carrier is a substrate and/or the material is glass or germanium, such as a wafer, lifting stress may also cause damage to the carrier. Metal foils are used in the prior art to provide regional stresses in the mold, but only partially, and the present invention further improves the limited stress in the prior art molds, thereby reducing damage to electronic components, components and carriers. . The invention is particularly applicable to electronic components located on a carrier, wherein the carrier can be a (矽) wafer, and/or a substrate having a plurality of planar structures, the substrate being provided with a carrier surface and an electrically conductive support structure.

In addition, the present invention can avoid another disadvantage of the use of a metal film in the conventional electronic component packaging technology, the compressive force of the metal film located between the contact faces of the electronic component and the model component, and the partial compression of a portion of the material of the metal film covering region. The material is laterally displaced to invade the electronic components surrounded by the metal film. Considering the reliability and aesthetics of the product, and considering the increasingly miniaturized/thinned packaging requirements, the above-mentioned compression violations are unacceptable. The microcolumn used in accordance with the present invention can prevent, or at least reduce, the occurrence of the above-described electronic components that invade the surrounding lamination. When used together with a metal film, the microcolumn of the present invention can be elastically modified to reduce the stress/load of the metal film, so that the metal film layer can be reused multiple times (used in multiple packaging cycles), unlike conventional techniques. Medium, the height difference compensation can only be provided by a metal film. Therefore, the invention can reduce the consumption of the metal film in the packaging process, thereby achieving the effect of reducing the process cost.

In one embodiment of the invention, the micropillars are vertically attached to the surface of the mold fitting. In general, the elasticity of the microcolumns in the vertical direction has a maximum value and an optimum stability. Particularly in the longitudinal direction of the microcolumns (the direction in which the micropillars extend), the micropillars provide the resilience required to compensate for the height difference of the packaged electronic components. Further controlling the elastic properties of the microcolumns and the stresses contained in the package structure can be achieved by arranging a plurality of microcolumns in an array.

In order to enable the microcolumn to face one side of a portion of the electronic component that is not covered by the encapsulating material, the microcolumn contacts the recessed portion of the contact surface of the mold cavity of the mold fitting.

In order for the microcolumn to effectively support the metal film layer, the microcolum is in contact with the surface of the model fitting, and its side away from the surface of the model fitting has a microsphere tip. The microsphere type described above at the tip of the microcolumn can increase the life of the microcolumn.

In addition, as in the prior art molds, the present invention uses a combination of micropillars, and at least one of the model fittings is provided with a suction passage opening to the contact side of the model fitting, and/or at least one of the model fittings is provided with a feed tube to enable The encapsulating material is embedded in the mold fitting and attached to the molding cavity.

The microcolumns of the present case can also be hollow structures to provide better flexibility of the microcolumns. The above microcolumns may also be referred to as "micro tubes" or "nano tubes" and may, for example, be tubular structures composed of carbon, germanium, boron nitride, polydimethyloxane. (PDMS) or other suitable material. The size of the microcolumns is at least 2,000 μm in height and 100 μm in cross section, and the number of microcolumns per square centimeter may be from several thousands to several millions. The micropillars can be fabricated, for example, by photolithography, etching, deposition, molding, or other suitable technique.

The present invention also provides a molding machine for encapsulating an electronic component on a carrier, comprising: a mold as described above, comprising at least two model fittings movable to each other, the at least two model fittings being disposed corresponding to each other, for example Corresponding contact sides with each other may be clamped or snapped to each other to form at least one mold cavity for surrounding the electronic component containing the package to be packaged, wherein at least one of the model fittings has a mold cavity embedded/recessed in the above model fitting The contact side, and wherein the mold fitting has a recessed mold cavity on the contact side having at least a portion of the surface having elastic micro-pillars, preferably elastic fiber micro-pillars (elastomeric micro-pillars) , that is, a microcolumn made of elastic fiber elastomer; a feeding tool to fill the encapsulating material into the molding cavity; and a driving system to move the corresponding model fitting to make the carrier be in contact with the model fitting Between the sides, at the same time provide controllable pressure, of which the model of the case The press is provided with a metal film processor to cover the micropillars attached to the surface of the mold fitting from one side away from the surface of the mold fitting. Therefore, the molding machine provided by the present invention can also achieve the efficacy of the mold of the present invention, please refer to the effects as described above. In particular, a combination of at least one model fitting having a structure of a plurality of micropillars and a metal film processor (normally designed as a metal foil feed roller and a metal foil discharge roller on the opposite side of the model fitting) for packaging In the process, a metal film covering a part of the electronic component is supported. The micropillars are in contact with a model fitting that provides elastic surface support. The metal film processor is configured to operate the metal film such that it can resist at least one of the molded mold parts. The combination of micropillar support and metal film, because the microcolumn can be used to compensate for the height difference between the packaged electronic components, thus reducing the process cost (due to the reduction in the use of metal film) and providing better molding results (less A metal film that does not have a plastically deformable property brings less dwelling, and a part of the electronic component that is not covered by the encapsulating material can have less mold penetration and/or a mold diffusion phenomenon. The metal film also allows the molded electronic component to be easily detached from the mold; such a metal film is referred to as a "release foil."

The molding machine is also provided with a suction tool connected to the suction passage, wherein the suction passage is open to the contact side of the model fitting, so that the metal film can be adsorbed on the model fitting (because of the low pressure in the suction passage), and It is attached to the micro-pillars of the model fittings, thus further supporting the positioning of the metal film on the model fittings (continuous stability in position).

The invention also provides a packaging method for packaging an electronic component on a carrier, comprising the steps of: A) covering a contact side of at least a portion of the model component with a metal film layer, the contact side of the covered component of the covered portion having At least one recessed cavity; B) placing a carrier having electronic components between at least two model fittings, wherein at least a portion of at least one of the model fittings is covered by a metal film layer; C) the model fittings are moved toward each other, To sandwich the carrier between the contact sides corresponding to the model fitting, and at least one molding cavity surrounding the electronic component to be packaged; D) placing the packaging material into the molding cavity; E) moving the model fittings away from each other And The carrier having the molded electronic component is removed from between the model fittings; wherein the metal film layer in the molding cavity is at least partially supported by the elastic microcolumn, and the elastic microcolumn is preferably an elastic fiber microcolumn connected to the surface of the model fitting Preferably, the surface of the mold part is recessed into a cavity. In particular, the electronic component to be molded can contact the metal film layer in the mold cavity. The above method facilitates the manufacture of the commonly known "bare crystal". For more explanation and efficacy, please refer to the above description of the mold and molding machine provided in this case. The microcolumns can be compressed and/or modified depending on the difference in height of the electronic components to be molded.

The encapsulation material is placed in the mold cavity surrounding the electronic component by applying pressure to the encapsulation material after the step C) is moved to the other. The above molding technique is also referred to as transfer moulding and compression moulding. In another molding method, the placement of the encapsulating material in step D) is performed before step C) the model fittings are moved toward each other. This molding process is also known as compression moulding. The molding method provided by the present invention can be applied independently. Generally, the encapsulating material is heated before or during molding, but the invention is not limited thereto.

The encapsulating material may be at least partially cured before the mold fitting moves away from each other in step E) so that the molded product does not lose its shape during the process of leaving the mold.

1‧‧‧Mold

2‧‧‧Electronic components

3‧‧‧ Carrier

4, 5‧‧‧ model accessories

6‧‧‧Molding cavity

7‧‧‧Metal film

8‧‧‧Packaging materials

9‧‧‧Chassis

10, 11‧‧‧ microcolumn

L ₁ , L ₂ ‧‧‧ length

The above and other objects, features, and advantages of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; Shown is a side view of a cross-sectional structure of the mold according to the present invention; FIG. 1B is a detailed structural view of the side view shown in FIG. 1A; 2A is a schematic view of the microcolumn when no pressure is applied; and FIGS. 2B-2D is a schematic view of the microcolumn shown in FIG. 2A under different pressure conditions.

1A, and a detailed structure FIG. 1B, which is a cross-sectional view of a mold 1 for encapsulating an electronic component 2 on a carrier 3. The mold 1 contains two model fittings: an upper model fitting 4 and a lower model fitting 5, which are mutually displaceable. As shown in Figures 1A and 1B, the model fittings 4 and 5 are moved towards each other to sandwich the carrier 3 between the contact sides of the two model fittings 4, 5. The molding cavity 6 of the upper mold fitting 4 is recessed inward, and the electronic component 2 can be contained therein. The metal film 7 is placed on the contact side of the upper mold fitting 4, and has the effect of lifting the electronic component after molding, and also allows the upper side of the electronic component 2 to be isolated from the packaging material 8. The encapsulating material 8 is placed between the mould parts 4, 5, in particular into the space of the moulding cavity 6 (i.e. at a position between the electronic components 2). In the mold cavity 6, the chassis 9 carries a large number of micropillars 10, preferably elastic fiber micropillars. The micropillar 10 telescopically and elastically supports the metal thin film 7, providing the advantages of the present invention as described above.

Micro-column 11 of FIG. 2A, for example, micro-column elastic fibers, the drawing is a schematic diagram of the micro-column 11 of the axial load is not administered / pressure conditions, not having load length L _1. 2B shows that when the pressure F is applied to the same microcolumn 11, the length is reduced to the effective support length L ₂ . The effective support length L ₂ is achieved by bending the micro-pillars 11. 2C shows the same microcolumn 11, also in the state where the pressure F is applied, and its length is reduced to the effective support length L ₂ , except that the length reduction in this embodiment is by compressing the microcolumn 11 itself. The effective support length L _{2 is} reached. 2D shows a combination of the two states of FIG. 2B and FIG. 2C, with the partial compression and partial bending of the micro-pillars 11 to achieve an effective support length L ₂ .

Claims (17)

A mold for encapsulating an electronic component on a carrier, comprising at least two model fittings, corresponding to each other and displacable to each other, by mutually corresponding one of the contact sides being respectively clamped to each other to form at least one mold cavity Surrounding the electronic component to be packaged, wherein at least one of the model fittings has a molding cavity recessed on the contact side, wherein the mold fitting has at least a recessed cavity on the contact side A portion of the surface has an elastic microcolumn. The mold of claim 1, wherein the micropillar is made of elastic fibers. The mold of any of claims 1 or 2, wherein the microcolumn is a hollow structure. The mold of any of claims 1 or 2, wherein the microcolum is in vertical contact with the surface of the mold fitting. A mold according to any one of claims 1 to 2, wherein a plurality of the micropillars are arranged in an array. The mold of any of claims 1 or 2, wherein the microcolum is in contact with the surface of the mold fitting and the side of the surface away from the mold fitting has a microsphere tip. A mold according to any one of claims 1 to 2, wherein at least one of the model fittings has a suction passage opening to the contact side of the mold fitting. A mold according to any one of claims 1 to 2, wherein at least one of the mold fittings has a feed tube coupled to the mold cavity to embed the packaging material in the mold fitting. A molding machine for encapsulating an electronic component on a carrier, comprising: a mold as claimed in claim 1; a feeding tool for filling a molding material into the molding cavity; a drive system for moving the corresponding model fittings to sandwich the carrier between the contact sides of the model fitting under controlled pressure; and a metal film processor to connect to the model fitting from the micro-pillar The other side of the surface covers the microcolumn. A molding press according to claim 9, wherein the metal film processor has a metal foil feed roller and a metal foil discharge roller, respectively located on opposite sides of the mold fitting. A molding press according to any one of claims 9 to 10, further comprising a suction tool coupled to a suction passage, wherein the suction passage opens to the contact side of the at least one of the mold fittings. A packaging method for encapsulating an electronic component on a carrier, comprising the steps of: A) covering at least one of the contact sides of one of the model fittings with a metal film layer, the contact of the covered component of the covered part a side having at least one recessed mold cavity; B) placing a carrier having electronic components between at least two model fittings, wherein at least one of the two model fittings has the at least one portion being the metal thin film layer Covering; C) moving the two model fittings toward each other to sandwich the carrier between the two contact sides of the two model fittings, and at least one of the molding cavities surrounding the electronic component to be packaged; D) placing a packaging material into the molding cavity; and E) moving the model fitting away from each other and removing the carrier having the molded electronic component from between the model fittings, wherein in the molding cavity The metal film layer is at least partially supported by a plurality of elastic micro-pillars attached to a surface of the mold cavity recessed on the mold fitting. The packaging method of claim 12, wherein the electronic component to be packaged is located in the molding cavity to contact the metal thin film layer. The encapsulation method according to any one of claims 12 or 13, wherein the step D) is performed after the step C), by applying pressure to the encapsulation material, the liquid encapsulation material enters the surrounding electrons. The molding cavity of the component. The encapsulation method of claim 14, wherein before the step E), further comprising: curing at least a portion of the encapsulation material. The encapsulation method of any one of claims 12 or 13, wherein the step D) is performed before the step C). The encapsulation method of claim 12, wherein the elastic microcolumn is an elastic fiber microcolumn.