Electronic component manufacturing process

Abstract

Method for manufacturing electronic components Method for manufacturing a hydrophobic electronic component (100) comprising a step during which a hydrophobic coating (170) is deposited on an electronic component (100) comprising a substrate (110), a chip (120) being positioned on a first face of the substrate (110), electrical connection terminals (140) being positioned on a second face of the substrate (110) and being electrically connected to the chip (120) by means of electrical tracks (130) passing through the substrate (110), a resin or a cover (150) covering the first face of the substrate (110) and the chip (120). Figure for abstract: Fig. 1E

Description

Title of the invention: Method for manufacturing electronic components Technical field

[0001] The present description relates to the manufacture of electronic components. It relates more particularly to the manufacture of electronic components of the box type. Prior art

[0002] Package-type electronic components typically comprise one or more chips disposed on the front face of a substrate made of non-conductive material. The chip(s) are protected from the external environment by a layer of resin that covers the front face of the substrate. Electrical contact terminals are positioned on the rear face of the substrate. Electrical tracks pass through the substrate and connect the chip(s) to the electrical terminals.

[0003] To be able to be used in humid environments, these electronic components must have good resistance to water and humidity.

[0004] To achieve such an objective, one solution is to use a ceramic substrate. However, with such substrates, it is not possible to miniaturize the components. Another solution would be to add an additional package, sealed from the environment, but this would increase the size of the electronic component and make it more difficult to install in a final product. Summary of the invention

[0005] There is a need to improve at least in part certain aspects of the known methods for manufacturing electronic components in order to obtain electronic components which are resistant to water and humidity and which can be miniaturized. This aim is achieved by a method for manufacturing a hydrophobic electronic component comprising a step during which a hydrophobic coating is deposited on an electronic component comprising a substrate, a chip being positioned on a first face of the substrate, electrical connection terminals being positioned on a second face of the substrate and being electrically connected to the chip by means of electrical tracks passing through the substrate, a resin or a cover covering the first face of the substrate and the chip.

[0006] According to a particular embodiment, the method comprises the following steps: - providing an element comprising several electronic components, - separating the electronic components, - fixing electrical connection pads on the electrical connection terminals, - depositing the hydrophobic coating so as to completely cover the electronic component.

[0007] According to a particular embodiment, the method further comprises a subsequent step during which the hydrophobic coating deposited on the electrical connection pads is removed.

[0008] According to a particular embodiment, the electrical connection pads are protected during the deposition of the hydrophobic coating.

[0009] According to a particular embodiment, the method comprises the following steps: - providing an element comprising several electronic components, - depositing the hydrophobic coating so as to cover the resin or the cover and the second face of the substrate, - carry out a step during which the hydrophobic coating deposited on the electrical terminals is removed, - possibly, fix electrical connection pads on the electrical terminals, - separate the electronic components.

[0010] According to a particular embodiment, the method comprises the following steps: - providing an element comprising several electronic components, - separating the electronic components, - apply the hydrophobic coating so as to completely cover the electronic component, - carry out a step during which the hydrophobic coating deposited on the electrical terminals is removed, - possibly, fix electrical connection pads on the electrical terminals.

[0011] According to a particular embodiment, the hydrophobic coating is a composite comprising a polymer material in which fillers are dispersed, preferably ceramic or graphene, and even more preferably, alumina or silica.

[0012] According to a particular embodiment, the substrate is made of a resin, preferably an epoxy resin, or of a composite material comprising fillers, such as glass fibers, dispersed in a resin, preferably an epoxy resin.

[0013] This object is also achieved by an electronic component comprising a substrate, a chip being positioned on a first face of the substrate, electrical connection terminals being positioned on a second face of the substrate and being electrically connected to the chip by means of electrical tracks passing through the substrate, a resin or a cover covering the first face of the substrate and the chip, a hydrophobic coating covering at least the resin or the cover and the second face of the substrate between the electrical connection terminals.

[0014] According to a particular embodiment, the hydrophobic coating is a composite comprising a polymer material in which fillers are dispersed, preferably ceramic or graphene, and even more preferably alumina or silica.

[0015] According to a particular embodiment, the substrate is made of a resin, preferably an epoxy resin, or of a composite material comprising fillers, such as glass fibers, dispersed in a resin, preferably an epoxy resin. Brief description of the drawings

[0016] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0017] [Fig.lA], [Fig.lB], [Fig.lC], [Fig.lD] and [Fig.lE] represent sectional views illustrating steps of a method of manufacturing an electronic component according to a particular embodiment;

[0018] [Fig.2A], [Fig.2B], [Fig.2C], [Fig.2D] and [Fig.2E] represent sectional views illustrating steps of a method of manufacturing an electronic component according to another particular embodiment; and

[0019] [Fig.3A], [Fig.3B], [Fig.3C], [Fig.3D] and [Fig.3E] represent sectional views illustrating steps of a method of manufacturing an electronic component according to another particular embodiment. Description of the embodiments

[0020] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0021] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed.

[0022] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0023] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0024] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0025] As shown in Figures 1A to 1E, 2A to 2E and 3A to 3E, the method for manufacturing a hydrophobic electronic component 100 comprises at least one step during which a hydrophobic coating 170 is formed on an electronic component 100. The electronic component 100 comprises a substrate 110, a chip 120 being positioned on a first face 111 of the substrate 110, electrical connection terminals 140 being positioned on a second face 112 of the substrate 110 and being electrically connected to the chip 120 by means of electrical tracks 130 passing through the substrate 110, a protective element 150, typically a resin or a cover, covering the first face 111 of the substrate 110 and the chip 120.

[0026] The hydrophobic coating 170 protects the electronic component 100 from the external environment, and in particular from water and humidity in the external environment.

[0027] The resistance to water and humidity obtained is comparable to that which would be obtained with a ceramic substrate. The lifetime of the component and its resistance to corrosion are thus improved.

[0028] Water and humidity resistances can be estimated, for example, according to J-STD-033D.

[0029] More particularly, the method advantageously comprises at least the following steps: a) providing an element 1000 comprising several electronic components 100, having a common substrate 110, each electronic component comprising one or more chips 120 arranged on the first face 111 of the substrate 110, electrical connection terminals 140 arranged on the second face 112 of the substrate 110, electrical tracks 130 connecting the chip(s) 120 to the electrical connection terminals 140, b) cutting the substrate 110 between the chips 120 to form individual electronic components 100, c) forming the hydrophobic coating 170.

[0030] The steps can be carried out in different orders: a), b) and c) or a), c) and b). In other words, the coating 170 can be deposited before singulating the components 100 or after singulating them.

[0031] Subsequently, we will more particularly describe assemblies of the 'Flip chip' type, that is to say assemblies with components of the BGA type (ball grid array) having connection pads 160 ('bump') positioned under the chip, but it could be a question of assemblies of the 'wire bond' type, that is to say assemblies with electronic components of the LGA type (ball grid array or “Land Grid Array”) for which wires, for example gold, silver or copper, are used to make the connection.

[0032] According to a first variant embodiment shown in Figures 1A to 1E, the method comprises the following steps: a) providing an element 1000 comprising several electronic components 100 ([Fig.lA]), d) fixing electrical connection pads 160 on the electrical connection terminals 140 ([Fig.IB]), b) cutting the substrate 110 to separate the different electronic components 100 ([Fig.lC]), c) forming the hydrophobic coating 170 ([Fig.lD]).

[0033] During step c), the coating preferably completely covers the electronic component 100. The coating can be formed in one or more times.

[0034] According to this first variant embodiment, the method may further comprise a step e) during which the hydrophobic coating 170 formed on the electrical connection pads is removed ([Fig. 1E]).

[0035] This removal step is, for example, carried out by chemical etching or by mechanical action, in particular by means of polishing.

[0036] Alternatively, and still according to this first embodiment variant, the method may comprise a step during which the electrical connection pads 160 are protected by a protective element during the formation of the hydrophobic coating 170.

[0037] After depositing the hydrophobic coating 170, the protective element is removed. For example, if, during the depositing of the hydrophobic coating 170, the component 100 is positioned on an adhesive support by gluing the connection pads 160 to this support, the connection pads 160 will not be completely covered by the coating 170. The adhesive support will be chosen so as to be sufficiently soft to allow the balls to be partially pushed into it. This embodiment is also compatible with electronic components of the LGA type (Land Grid Array).

[0038] According to a second variant embodiment, shown in FIGS. 2A to 2E, the method comprises the following steps: a) providing an element 1000 comprising several electronic components 100 ([Fig.2A]), c) depositing the hydrophobic coating 170 on the resin and on the second face 112 of the substrate 110 ([Fig.2B]), e) carrying out a step during which the hydrophobic coating 170 deposited on the electrical terminals 140 is removed, for example by etching ([Fig.2C]), d) preferably, fixing electrical connection pads 160 on the electrical terminals 140 ([Fig.2D]), b) separate the different electronic components 100 ([Fig.2E]).

[0039] According to a third variant embodiment, shown in FIGS. 3A to 3E, the method comprises the following steps: a) providing an element 1000 comprising several electronic components 100 ([Fig.3A]), b) separate the different electronic components 100 ([Fig.3B]), c) depositing the hydrophobic coating 170 so as to completely cover the electronic component ([Fig.3C]), e) etching the hydrophobic coating 170 to make the electrical connection terminals 140 accessible ([Fig.3D]), d) optionally, fixing electrical connection pads 160 on the electrical terminals 140 ([Fig.3E]).

[0040] According to this third embodiment variant, it is possible to manufacture electronic components of the BGA type (ball grid array) or of the LGA type (land grid array), depending on whether or not step d is carried out.

[0041] We will describe in more detail the steps of these different embodiment variants.

[0042] The element 1000 provided in step a) comprises several electronic components 100, each electronic component 100 comprising at least one chip 120, a substrate 110 and a protection element 150. The substrate 110 is common to the different electronic components 100. The element 1000 preferably has a matrix format ('Matrix BGA' or 'Matrix LGA').

[0043] The chip 120 may comprise one or more discrete components. The discrete component(s) are, for example, chosen from transistors, diodes, thyristors, triacs, filters, etc. The chip 120 may comprise one or more electronic circuits. The chip 120 makes it possible to implement different electronic functions. By way of illustration, capacitors and inductors may be mentioned.

[0044] The electronic component 100 is a so-called integrated component.

[0045] In step a), the manufacture of the discrete component(s) and / or integrated circuits forming the electronic components 100 is completed. The components 100 have not yet been individualized.

[0046] The substrate 110 comprises a first face 111 (upper face or front face) and a second face 112 (lower face or rear face).

[0047] The chips 120 are fixed on the first face 111 of the substrate 110. In the figures, only one chip 120 is shown for each component 100, but the components electronics may include multiple 120 chips.

[0048] The substrate 110 comprises an electrically insulating material in which the electrical tracks 130 are formed. The electrically insulating material may be a resin, a polymer or a composite material comprising a resin or a polymer in which non-conductive fillers, such as glass fibers, are dispersed. The resin is preferably an epoxy type resin.

[0049] Electrical tracks 130 of the substrate 110 run from the first face 111 of the substrate 110 to the second face 112 of the substrate 110 so as to allow the chip 120 to be connected to an external device. The electrical tracks 120 pass right through the substrate 110.

[0050] The tracks 130 are for example made of copper.

[0051] Electrical connection terminals 140 (also called electrical connection pads or electrical contacts) are positioned on the second face 112 of the substrate 110. They are connected to the electrical tracks 130 of the substrate 110.

[0052] They are made of a conductive material specifically adapted to allow the attachment of the connection pads 160. The electrical connection terminals 140 comprise at least one of the following elements: gold, titanium, nickel, copper, silver, tin or tungsten. Preferably, they comprise gold or copper. They can be covered with a metal layer (“plating”).

[0053] Preferably, the substrate 110 and the electrical tracks 130 form a printed circuit (PCB type for “Printed Circuit Board”).

[0054] The chip 120 is protected by a protection element 150. It covers the first face 111 of the substrate 110 and the chip 120. More particularly, the upper face and the sides of the chip 120 are protected by this element 150. The lower face of the chip 120 is opposite the substrate 110.

[0055] The protective element 150 may be a layer of insulating material 150, preferably a layer of resin.

[0056] For example, the resin comprises at least one base material to which electrically insulating particles are added. The base material is chosen, for example, from the group comprising: epoxy type resins, and phenolic type resins, acrylic type resins. Preferably, it is an epoxy type resin. The particles are, for example, oxide particles, and in particular alumina or silica particles.

[0057] The resin can be polymerized under ultraviolet (UV) radiation or by thermal activation. Annealing can be carried out.

[0058] The resin can be deposited by injection ('molding').

[0059] The resin is, for example, molded onto the substrate 110 and the chip 120.

[0060] Alternatively, the protective element 150 is a cover 150, made of metal or plastic, in contact or not with the chip 120.

[0061] During step b), the different electronic components 100 are separated from each other. This step is carried out by cutting the substrate 110 and the resin layer 150 between the chips 120.

[0062] This singulation step is carried out by means of a cutting device. The cutting device is, for example, a mechanical cutting tool such as a saw, or a laser or plasma engraving tool. According to another embodiment, the cutting device is a laser.

[0063] During step c) the hydrophobic coating 170 is formed.

[0064] The hydrophobic coating 170 is preferably a composite material comprising a polymer in which fillers are dispersed. The fillers are preferably non-conductive.

[0065] The fillers may be ceramic or carbon material such as graphene.

[0066] In particular, oxide fillers will be chosen, preferably alumina, yttrium, zirconia or silica fillers.

[0067] Alternatively, organometallic complexes or transition metal complexes may be used.

[0068] The hydrophobic coating 170 has a thickness of between 2 nm and 20 pm.

[0069] The coating may be deposited in the gas phase or in the liquid phase. The liquid phase may contain an organic solvent.

[0070] Preferably, before forming the coating 170, a drying step ('bake') is carried out, for example at a temperature between 80 and 140°C, preferably between 90 and 130°C. This step makes it possible to remove any trace of humidity before forming the hydrophobic coating 170.

[0071] When the coating 170 is deposited on the element 1000 ([Fig.2B]), the sides of the electronic components 100 will not be covered by the hydrophobic coating 170 during step b). Only the first face (front face) and the second face (rear face) of the components may be covered by the hydrophobic coating 170 during this step.

[0072] When the hydrophobic coating 170 is deposited on the previously individualized electronic components 100 ([Fig. 1D] and [Fig. 3C]), it can be deposited on the first face, the second face and the sides of each electronic component 100. This embodiment leads to better protection against humidity. It is possible to form the hydrophobic coating in several steps, for example by forming the coating on the front face then on the rear face or vice versa. The sides can be covered by the coating at the same time as the front face or at the same time as the rear face.

[0073] During step d), the electrical connection pads 160 are fixed on the terminals 140 electrical connection.

[0074] The connection pads 160 are, for example, balls. The balls have a diameter of between 50 μm and 900 μm and preferably between 150 μm and 800 μm.

[0075] The electrical connection pads are, for example, made of a tin alloy, preferably a tin-silver-copper alloy (denoted SnAgCu or SAC).

[0076] This step can be carried out by soldering.

[0077] The soldering material may be pre-deposited on the connection terminals 140. It may be deposited by a printing technique, preferably by screen printing. It may be any additive deposition technique. The soldering material may be Sn, or a tin alloy such as SnAgCu or SnAg or another alloy with a higher melting point.

[0078] During step e), the hydrophobic coating 170 is removed locally in order to release the electrical connection pads 160 and / or the electrical connection terminals 170.

[0079] This step can be carried out by chemical etching, using a masking step.

[0080] A mechanical removal step can also be carried out, in the case where it is desired to remove a portion of the coating 170 positioned on the pads 160. This embodiment is advantageous in the case of pads 160 of large dimensions (typically of dimensions greater than 350 μm in diameter).

[0081] At the end of the method, the electronic components 100 each comprise a substrate 110, one or more chips 120 arranged on a first face 111 of the substrate, a resin 150 covering the substrate 110 and the chip(s) 120, electrical connection terminals 140 arranged on a second face 112 of the substrate 110. Electrical tracks 130 electrically connect the chip(s) 120 to the electrical connection terminals 140. A hydrophobic coating 170 covers at least the protective element 150 and the second face 112 of the substrate 110 between the electrical connection terminals 140. The hydrophobic coating 170 may also cover the sides of the electronic component 100.

[0082] Connection pads 160 may be attached to the electrical connection terminals 140.

[0083] Such components 100 may be attached to an external device, for example, a printed circuit board or other component.

[0084] These electronic components 100 have applications in numerous industrial fields and, in particular, in the automotive, aerospace or naval fields (in particular for use on / in boats) or for devices intended to be placed in humid rooms, such as in bathrooms, in underground locations, outdoors.

[0085] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art.

[0086] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. A method of manufacturing a hydrophobic electronic component (100) comprising a step during which a hydrophobic coating (170) is deposited on an electronic component (100) comprising a substrate (110), a chip (120) being positioned on a first face (111) of the substrate (110), electrical connection terminals (140) being positioned on a second face (112) of the substrate (110) and being electrically connected to the chip (120) by means of electrical tracks (130) passing through the substrate (110), a resin or a cover (150) covering the first face (111) of the substrate (110) and the chip (120).

2. Method according to claim 1, comprising the following steps: - providing an element (1000) comprising several electronic components (100), - separating the electronic components (100), - fixing electrical connection pads (160) on the electrical connection terminals (140), - depositing the hydrophobic coating (170) so as to completely cover the electronic component (100).

3. The method of claim 2, further comprising a subsequent step in which the hydrophobic coating (170) deposited on the electrical connection pads (160) is removed.

4. The method of claim 2, wherein the electrical connection pads (160) are protected during the deposition of the hydrophobic coating (170).

5. Method according to claim 1, comprising the following steps: - providing an element (1000) comprising several electronic components (100), - depositing the hydrophobic coating (170) so as to cover the resin or the cover (150) and the second face (112) of the substrate (110), - carrying out a step during which the hydrophobic coating (170) deposited on the electrical terminals (140) is removed, - optionally, fixing electrical connection pads (160) on the electrical terminals (140), - separating the electronic components (100).

6. Method according to claim 1, comprising the following steps: - providing an element (1000) comprising several electronic components (100), - separating the electronic components (100), - depositing the hydrophobic coating (170) so as to completely cover the electronic component (100), - carrying out a step during which the hydrophobic coating (170) deposited on the electrical terminals (140) is removed, - possibly, fixing electrical connection pads (160) on the electrical terminals (140).

7. Method according to any one of the preceding claims, in which the hydrophobic coating (170) is a composite comprising a polymer material in which fillers are dispersed, preferably ceramic or graphene, and even more preferably, alumina or silica.

8. A method according to any preceding claim, wherein the substrate (110) is made of a resin, preferably an epoxy resin, or a composite material comprising fillers, such as glass fibers, dispersed in a resin, preferably an epoxy resin.

9. An electronic component (100) comprising a substrate (110), a chip (120) being positioned on a first face (111) of the substrate (110), electrical connection terminals (140) being positioned on a second face (112) of the substrate (110) and being electrically connected to the chip (120) by means of electrical tracks (130) passing through the substrate (110), a resin or a cap (150) covering the first face (111) of the substrate (110) and the chip (120), a hydrophobic coating (170) covering at least the resin or the cap (150) and the second face (112) of the substrate (110) between the electrical connection terminals (140).

10. Component according to claim 9, in which the hydrophobic coating (170) is a composite comprising a polymer material in which fillers are dispersed, preferably ceramic or graphene, and even more preferably alumina or silica.

11. A component according to any one of claims 9 and 10, wherein the substrate (110) is made of a resin, preferably an epoxy resin, or of a composite material comprising fillers, such as glass fibers, dispersed in a resin, preferably an epoxy resin.

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