Layer structure comprising a semiconductor package

Abstract

Layer structure 200 comprises a first insulating layer 203, a second insulating layer 207, and an electrically conductive layer 205 positioned between the first and second insulating layers. A biosens

Description

The present invention is directed towards a layer structure comprising a semiconductor package. The present invention is directed, in particular towards a layer structure comprising a semiconductor package that performs sensing functions which will otherwise be referred to as a sensor semiconductor package. Background Referring to Figure A there is shown an article 20 according to existing implementations. The article 20 comprises a textile material 21. A sensor 10 is provided on the textile material 21. The sensor 10 comprises a controller 11 and a pair of electrodes 13. The pair of electrodes 13 are connected to the controller 11 by wires 15. The controller 11 may be in the form of a semiconductor package. It is an objective of the present disclosure to overcome at least some of the problems associated with the prior art, whether explicitly discussed herein or otherwise. Summary According to the present disclosure there is provided a layer structure, article and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows. According to a first aspect of the disclosure, there is provided a layer structure for application to a surface. The layer structure comprises a first insulating layer; a second insulating layer; and an electrically conductive layer positioned between the first insulating layer and the second insulating layer. The layer structure further comprises a sensor semiconductor package provided on the electrically conductive layer. The sensor semiconductor package comprises a first external connection terminal electrically connected to the electrically conductive layer; a second external connection terminal electrically connected to the electrically conductive layer; a semiconductor chip electrically connected to the first external connection terminal and the second external connection terminal; and a sealing member covering the first and second external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals. Advantageously, the present disclosure provides a layer structure which incorporates a sensor semiconductor package. The sensor semiconductor package is electrically connected to a conductive layer of the layer structure. Beneficially, this enables the effective and simple integration of sensor semiconductor packages onto an article. The layer structure can simply be attached to the article and an electronics module can be connected to the sensor semiconductor package via the conductive layer. Individually mounting a sensor semiconductor package on an article and connecting the sensor semiconductor package to an electronics module via a wire is thus avoided. The layer structure may comprise a transfer layer. The first insulating layer may be provided on the transfer layer. The layer structure may comprise an adhesive layer. The adhesive layer may be provided on the second insulating layer. The first or second insulating layer may comprise one or more openings. These openings may serve as contact points to allow for an external electronics module to electrically connect to the conductive layer so as to communicate with the sensor semiconductor package. The sensor semiconductor package may further comprise a die pad. The semiconductor chip may be located on a top surface of the die pad, and the sealing member may cover the die pad and expose an outer contact surface of the die pad. The first insulating layer may comprise an opening aligned with the outer contact surface of the die pad such that at least part of the outer contact surface of the die pad is not covered by the first insulating layer. The electrically conductive layer may comprise an opening aligned with the outer contact surface of the die pad such that at least part of the outer contact surface of the die pad is not covered by the electrically conductive layer. The sensor semiconductor package may be electrically connected to the die pad, and the outer contact surface of the die pad may form an electrode of the sensor semiconductor package. The present disclosure provides a sensor in the form of a semiconductor package. The electrode(s) of the sensor are incorporated into the semiconductor package. Beneficially, this means that the form factor of the sensor is reduced compared to existing sensors which provide electrodes physically spaced apart from a controller of the sensor. The sensor semiconductor package utilises the exposed outer contact surface of the die pad as the electrode forthe sensor. Die pads are provided in existing semiconductor packages as heatsinks and are not electrically connected to the semiconductor chip. In this way a self-contained semiconductor package for performing sensing functions using an integral electrode is provided utilising existing semiconductor package structures, and requiring minimal changes to existing, established, semiconductor package manufacturing techniques. At least one wire may extend from the semiconductor chip to connect the semiconductor chip to the at least one die pad. A plurality of wires may extend from the semiconductor chip to connect the semiconductor chip to the plurality of external connection terminals. The die pad may comprise a first die pad and a second die pad. The semiconductor chip may be located on a top surface of one or both of the first die pad and the second die pad. The semiconductor chip may be electrically connected to the first die pad and the second die pad. The sealing member may expose an outer contact surface of the first die pad. The sealing member may expose an outer contact surface of the second die pad. The outer contact surface of the first die pad may form a first electrode of the sensor semiconductor package. The outer contact surface of the second die pad may form a second electrode of the sensor semiconductor package. The semiconductor chip may be arranged to receive a measurement signal from the die pad, and optionally perform at least one processing operation on the receive measurement signal. The semiconductor chip may be attached to the top surface of the at least one die pad by an adhesive. The conductive layer may comprise a first conductive trace and a second conductive trace. The first conductive trace may be electrically connected to the first external connection terminal, and the second conductive trace may be electrically connected to the second external connection terminal. The first conductive trace may be a bidirectional line for the article, and wherein the semiconductor chip of the sensor semiconductor package may be arranged to send and / or receive data over the bidirectional line. The bidirectional line may be a single-wire bidirectional line, and wherein the semiconductor chip of the sensor semiconductor package sends and / or receives data over the singe-wire bidirectional line using a single-wire communication protocol. The second conductive trace may be a return line for the article, and wherein the semiconductor chip of the sensor semiconductor package is connected to ground via the return line. The first and second insulating layers may comprise non-conductive ink. The conductive layer may comprise conductive ink. The sensor semiconductor package may comprise an electrode (or a plurality of electrodes) electrically connected to the semiconductor chip. The sensor semiconductor package may be a first sensor semiconductor package. The layer structure may further comprise a second sensor semiconductor package. The second sensor semiconductor package may comprise: a first external connection terminal; a second external connection terminal; a semiconductor chip electrically connected to the first external connection terminal and the second external connection terminal; and a sealing member covering the first and second external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals. The second sensor semiconductor package may be provided on the electrically conductive layer. The first and second external connection terminals of the second sensor semiconductor package may be electrically connected to the conductive layer. The sensor semiconductor package may be a biosensor semiconductor package for monitoring a biosignal of a living body. The biosignal may be one or more of a bioelectrical signal, a biopotential signal, and a bioimpedance signal of the living body. The biosensor semiconductor package may be an electrocardiography semiconductor sensor package and / or an electromyography semiconductor sensor package. An electrode of the biosensor semiconductor package may be for monitoring a biosignal of a living body. The electrode of the biosensor semiconductor package may be for monitoring a bioelectrical signal of the living body. The electrode of the biosensor semiconductor package may be for monitoring a biopotential signal of the living body. The electrode of the biosensor semiconductor package may be for monitoring a bioimpedance signal of the living body. The biosensor semiconductor package may be an electrocardiography semiconductor sensor package. The biosensor semiconductor package may be an electromyography semiconductor sensor package. According to a second aspect of the disclosure, there is provided an article. The article comprises the layer structure of the first aspect of the disclosure. The layer structure is attached to a surface of the article. The article may further comprise an electronics module, the electronics module comprising a power source, a processor and a memory, wherein the electronics module is arranged to be electrically connected to the electrically conductive layer of the layer structure and is further arranged to communicate with the sensor semiconductor package via the electrically conductive layer. The electronics module may be removable from the article, optionally wherein the article comprises an electronics module holder for at least temporarily holding the electronics module. The electronics module holder may be a pocket of the article. The article may be a wearable article. The wearable article may be a garment. The present disclosure is not limited to wearable articles. The sensor semiconductor packages disclosed herein may be incorporated into other forms of devices such as user electronic devices incorporating a textile material. In additions, the sensor semiconductor packages as disclosed herein may be incorporated into any form oftextile article. Textile articles may include upholstery, such as upholstery that may be positioned on pieces of furniture, vehicle seating, as wall or ceiling decor, among other examples. The sensor semiconductor package may be a biosensor semiconductor package for monitoring a biosignal of a living body, optionally wherein the biosignal is one or more of a bioelectrical signal, a biopotential signal, and a bioimpedance signal of the living body, optionally wherein the biosensor semiconductor package is an electrocardiography semiconductor sensor package and / or an electromyography semiconductor sensor package. According to a third aspect of the disclosure, there is provided a method for manufacturing a layer structure. The method comprises printing non-conductive ink onto a transfer layer to produce a first insulating layer; printing an electrically conductive ink onto said first non-conductive printed ink layer to produce an electrically conductive layer; providing a sensor semiconductor package, wherein the sensor semiconductor package comprises: a first external connection terminal; a second external connection terminal; a semiconductor chip electrically connected to the first external connection terminal and the second external connection terminal; and a sealing member covering the first and second external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals; positioning the sensor semiconductor package on the electrically conductive layer such that the electrically conductive layer is electrically connected to the first and second external connection terminals; and printing non-conductive ink over said electrically conductive layer to produce a second insulating layer. The method may further comprise applying an adhesive over the second insulating layer to produce an adhesive layer. Providing the sensor semiconductor package may comprise providing at least one die pad and a plurality of external connection terminals; providing a semiconductor chip; locating the semiconductor chip on a top surface of the at least one die pad; electrically connecting the semiconductor chip to the plurality of external connection terminals and the at least one die pad; forming a sealing member covering the die pad, the plurality of external connection terminals and the semiconductor surface and exposing an outer terminal of each of the plurality of external connection terminals and an outer contact surface of the at least one die pad, wherein the outer contact surface of the at least one die pad forms an electrode of the sensor semiconductor package. Advantageously, the present disclosure provides a method for manufacturing a sensor semiconductor package which requires minimal modification to existing semiconductor package manufacturing techniques. In this way, the sensor semiconductor package according to the present disclosure is able to be manufactured rapidly, at scale, and at low cost. The sensor semiconductor packages may be provided in a method for manufacturing a plurality of sensor semiconductor packages. The method may comprise providing a lead frame comprising a plurality of regions arranged to be separated from one another to provide the plurality of semiconductor packages. Each of the plurality of regions may comprise at least one die pad and a plurality of external connection terminals. The method may further comprise providing a plurality of semiconductor chips, and, for each of the regions, locating a semiconductor chip on a top surface of the at least one die pad. The method may further comprise, for each of the regions, electrically connecting the semiconductor chip to the plurality of external connection terminals and the at least one die pad. The method may further comprise, for each of the regions, forming a sealing member covering the die pad, the plurality of external connection terminals and the semiconductor surface and exposing an outer terminal of each of the plurality of external connection terminals and an outer contact surface of the at least one die pad, wherein the outer contact surface of the at least one die pad forms an electrode of the sensor semiconductor package. The method may further comprise separating the plurality of regions from one another to form the plurality of sensor semiconductor packages. According to a fourth aspect of the disclosure, there is provided a method for manufacturing an article. The method comprises providing a layer structure according to the first or third aspect of the disclosure and attaching the layer structure to the article. The article may be the article of the second aspect of the disclosure. Brief Description of the Drawings Examples of the present disclosure will now be described with reference to the accompanying drawings, in which: Figure A is schematic diagram of an example sensor according to a prior art implementation; Figure 1 is a perspective view of an example sensor semiconductor package according to aspects of the present disclosure; Figure 2 is a bottom view of the sensor semiconductor package of Figure 1; Figure 3 is a plan view of the sensor semiconductor package of Figure 1 with the sealing member removed; Figure 4 is a perspective view of the sensor semiconductor package of Figure 1 with the sealing member removed; Figure 5 is a perspective view of another example sensor semiconductor package according to aspects of the present disclosure; Figure 6 is a bottom view of the sensor semiconductor package of Figure 5; Figure 7 is a plan view of the sensor semiconductor package of Figure 5 with the sealing member removed; Figure 8 is a perspective view of the sensor semiconductor package of Figure 5 with the sealing member removed; Figure 9 is a cross-sectional view of a layer structure according to aspects of the present disclosure; Figure 10 is a bottom view of the layer structure of Figure 9; Figure 11 is a cross-sectional view of an example article according to aspects of the present disclosure; Figure 12 is a schematic diagram of an example article according to aspects of the present disclosure; Figure 13 is a simplified diagram showing a user wearing an article according to aspects of the present disclosure; Figure 14 is a flow diagram of an example method of manufacturing a sensor semiconductor package according to aspects of the present disclosure; and Figure 15 is a flow diagram of an example method of manufacturing an article according to aspects of the present disclosure. Detailed Description The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness. The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the disclosure is provided for illustration purpose only and not for the purpose of limiting the disclosure as defined by the appended claims and their equivalents. It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. “Wearable article” as referred to throughout the present disclosure may refer to any form of electronic device which may be worn by a user such as a smart watch, necklace, bracelet, or glasses. The wearable article may be a textile article. The wearable article may be a garment. The garment may refer to an item of clothing or apparel. The garment may be a top. The top may be a shirt, t-shirt, blouse, sweater, jacket / coat, or vest. The garment may be a dress, brassiere, shorts, pants, arm or leg sleeve, vest, jacket / coat, glove, armband, underwear, headband, hat / cap, collar, wristband, stocking, sock, or shoe, athletic clothing, personal protection equipment, swimwear, wetsuit or drysuit The wearable article / garment may be constructed from a woven or a non-woven material. The wearable article / garment may be constructed from natural fibres, synthetic fibres, or a natural fibre blended with one or more other materials which can be natural or synthetic. The yarn may be cotton. The cotton may be blended with polyester and / or viscose and / or polyamide according to the particular application. Silk may also be used as the natural fibre. Cellulose, wool, hemp and jute are also natural fibres that may be used in the wearable article / garment. Polyester, polycotton, nylon and viscose are synthetic fibres that may be used in the wearable article / garment. The garment may be a tight-fitting garment. Beneficially, a tight-fitting garment helps ensure that the sensor devices of the garment are held in contact with or in the proximity of a skin surface of the wearer. The garment may be a compression garment. The garment may be an athletic garment such as an elastomeric athletic garment. Referring to Figures 1 to 4, there is shown a sensor semiconductor package 100 according to aspects of the present disclosure. The sensor semiconductor package 100 comprises a single die pad 101 (Figure 2). The die pad 101 is provided in a central region of the sensor semiconductor package 100. The sensor semiconductor package 100 comprises a plurality (twenty-eight in this example) of external connection terminals 103. The plurality of external connection terminals 103 are located around the die pad 101. The sensor semiconductor package 100 has a rectangular bottom surface. The plurality of external connection terminals 103 are provided along the four sides of the rectangular bottom surface. The die pad 101 is provided in the centre of the rectangular shape and has a substantially rectangular shape. In this specification, the term “rectangular” encompasses “square”. The present disclosure is not limited to any particular number of external connection terminals. The die pad 101 is formed of a conductive material. Generally, the die pad 101 is formed of a metal material having high mechanical strength, high electrical conductivity, and high resistance against corrosion. The metal material may also be desired to have high heat conductivity to enable the die pad 101 to transfer heat away from the semiconductor chip 105. This enables the die pad 101 to simultaneously function as an electrode and a heatsink. Example metal materials which may be used for the die pad 101 include copper-based materials such as copper alloys containing iron, phosphorous or the like. Other example metal materials which may be used for the die pad 101 include iron-based materials such as an iron alloy containing nickel or the like. The external connection terminals 103 include an inner terminal 119 close to the die pad 101 and an outer terminal 115 further from the die pad 101 when compared to the inner terminal 119. The inner terminals 119 have a curved shape in this example, but that is not required in all aspects of the present disclosure. The external connection terminals 103 may, for example, have a rectangular shape. The outer terminals 115 may, for example, be curved or have a protruding portion. The external connection terminals 103 may have any structure as used in existing semiconductor packages. The external connection terminals 103 are generally preferred to be made of the same material as the die pad 101. The sensor semiconductor package 100 further comprises a semiconductor chip 105 (Figure 3) located on a top surface of the die pad 101 and electrically connected with the plurality of external connection terminals and the die pad. The semiconductor chip 105 is attached to the die pad 101 by an adhesive (not shown). A wire 109 extends from the semiconductor chip 105 to connect the semiconductor chip 105 to the die pad 101. A plurality of wires 111 extend from the semiconductor chip 105 to connect the semiconductor chip 105 to each of the external connection terminals 103. The wires 109, 111 may be formed of a material such as gold or copper. Other materials that provide the required conductivity and connectability may also be used. The sensor semiconductor package 100 further comprises a sealing member 113 (Figure 1). The sealing member 113 covers the die pad 101, the plurality of external connection terminals 103, and the semiconductor chip 105. The sealing member 113 exposes an outer terminal 115 of each of the plurality of external connection terminals 103 and an outer contact surface 117 of the die pad 101. The outer contact surface 117 of the die pad 101 forms an electrode 117 of the sensor semiconductor package 100. The outer contact surface 117 of the die pad 101 is the exposed bottom surface 117 of the die pad 101 as best shown in Figure 2. The outer terminals 115 of the plurality of external connection terminals 103 are the exposed bottom surfaces 115 and exposed side surfaces 115 of the external connection terminals 103 that project out of the sealing member 113 as best shown in Figures 1 and 2. The sealing member 113 comprises a sealing material which encapsulates the semiconductor chip 105, die pad 101 and external connection terminals 103 of the sensor semiconductor package 100. In this arrangement, the amount of air in the sensor semiconductor package 100 is minimized. In other examples, the sealing member may have an internal air-cavity. In these examples, the sealing member typically comprises a plastic-moulded body (open, and not sealed), and a lid which covers the plastic moulded body. The lid may be a ceramic or plastic lid, for example. The sealing material may be a plastic material and may, in particular, be a thermosetting resin. An example of a useable thermosetting resin is an epoxy resin. The sensor semiconductor package 100 performs sensing functions and, beneficially, utilises the exposed outer contact surface 117 of the die pad 101 as an electrode 117 for the sensor semiconductor package 100. Die pads are provided in existing semiconductor packages as heat sinks and are not electrically connected to the semiconductor chip. The present disclosure advantageously, utilises the existing die pad of semiconductor packages as an electrode and electrically connects the die pad to the semiconductor chip such that the semiconductor chip may receive measurement signals from the electrode. In this way a self-contained semiconductor package 100 for performing sensing functions using an integral electrode is provided utilising existing semiconductor package structures, and requiring minimal changes to existing, established, semiconductor package manufacturing techniques. Conventionally, a sensor semiconductor package is connected to a separate, standalone, electrode via a conductor extending from one or more of the external connection terminals. The semiconductor chip 105 of the sensor semiconductor package 100 receives measurement signals from the electrode 117 and may perform one or more processing operations on the received measurements signals. The one or more processing operations may include signal processing operations which may comprise filtering, smoothing, or interpolation operations. The one or more processing operations may include feature extraction operations to extract one or more features from the (processed) measurement signals. The semiconductor chip 105 may comprise a controller. The controller may be a microcontroller. The controller may comprise a processor and a memory. The memory may store instructions which, when executed by the processor, cause the processor to perform one or more operations. The semiconductor chip 105 may comprise a data store for storing sensor data. The semiconductor chip 105 is arranged to send and / or receive data via at least one of the external connection terminals 103. The at least one external connection terminal 103 is, in use, electrically connected a communication line to allow for data to be sent and / or received from the semiconductor chip 105. The communication line may be a bidirectional communication line to allow for data to be sent and received. At least one of the external connection terminals 103 functions as a ground for the semiconductor chip. The semiconductor chip 105 may comprise additional circuitry for performing sensing functions. The semiconductor chip 105 may comprise circuitry for performing one or more of temperature sensing, humidity sensing, and motion sensing. In other words, the semiconductor chip 105 may comprise a temperature sensor, a humidity sensor, or a motion sensor. The motion sensor may comprise one or more of an accelerometer, gyroscope, and magnetometer. The motion sensor may comprise an inertial measurement unit. Referring to Figures 5 to 8, there is shown another sensor semiconductor package 100’ according to aspects of the present disclosure. The sensor semiconductor package 100’ has a similar structure to the sensor semiconductor package 100 shown in Figures 1 to 4 and like reference numerals have been used to show like components. Importantly, the sensor semiconductor package 100’ of Figures 5 to 8 comprises a plurality of die pads and in particular includes a first die pad 101 and a second die pad 101 ’. The semiconductor chip 105 is positioned such that it straddles the top surface of both the first die pad 101 and the second die pad 101’. The semiconductor chip 105 is electrically connected to the first die pad 101 by a first wire 109 and is electrically connected to the second die pad 101’ by a second wire 109’. The sealing member 113 exposes an outer contact surface 117 of the first die pad 101 and an outer contact surface 117’ of the second die pad 10T. The outer contact surface 117 of the first die pad 101 forms a first electrode 117of the sensor semiconductor package 100’. The outer contact surface 117’of the second die pad 101’ forms a second electrode 117’ of the sensor semiconductor package 100’. This arrangement therefore provides a sensor semiconductor package 100’ with two integral electrodes 117, 117’. The two integral electrodes 117,117’ may form first and second electrodes 117,117’ of a bioelectrical sensor such an electrocardiography sensor. The two integral electrodes 117, 117’ may for bipolar electrodes 117, 117’ of an electromyography sensor and in particular a surface electromyography sensor. Referring to Figure 9, there is shown a cross-sectional view of a layer structure 200 according to aspects of the present disclosure. The layer structure 200 comprises a first insulating layer 203 and a second insulating layer 207. An electrically conductive layer 205 is positioned between the first insulating layer 203 and the second insulating layer 207. A sensor semiconductor package 100 is provided on the electrically conductive layer 205. The sensor semiconductor package 100 is the package 100 of Figures 1 to 4. Additionally or separately, the layer structure 200 may comprise the sensor semiconductor package of Figures 5 to 8. A first external connection terminal of the sensor semiconductor package 100 is electrically connected to the electrically conductive layer at connection point 211. A second external connection terminal is electrically connected to the electrically conductive layer 203 at connection point 213. The layer structure 200 additionally comprises a transfer layer 201 onto which the first insulating layer 203 is provided. The first insulating layer 203 and the electrically conductive layer 205 include an opening which exposes the electrode 117 of the sensor semiconductor package 100. This means that the electrode 117 is not covered by the electrically conductive layer 205 or the first insulating layer 203. The first insulating layer 203 is a non-conductive ink layer 203 comprising a non-conductive ink. The second insulating layer 207 is a non-conductive ink layer 207 comprising a non-conductive ink. The non-conductive ink layer may be any suitable printing ink which is non-conductive. The electrically conductive layer 205 comprises an electrically conductive ink. The electrically conductive ink may be any suitable electrically conductive ink. The layer structure 200 further comprises a transfer layer 201. The first insulating layer 203 is provided on the transfer layer 201. The transfer layer 201 is not required to have an opening to expose the electrode 117 because the transfer layer 201 is removed once the layer structure 200 is attached to an article. The transfer layer 201 may be any suitable layer onto which ink may be printed. The transfer layer 201 may be a polyester film or paper film for example. The layer structure 200 further comprises an adhesive layer 209. The adhesive layer 209 covers the second insulating layer 207 and the sensor semiconductor package 100. Adhesive layer 209 is used to adhere the layer structure 200 to a surface. The adhesive layer 209 may comprise a water based adhesive, a solvent based adhesive, a printable adhesive, a powder adhesive or any other suitable adhesive which is capable of the layer structure 200 to a surface. The adhesive layer 209 may be a printable adhesive In the example of Figure 9, the second insulating layer 207 does not cover the sensor semiconductor package 100. This is not required in all embodiments. The sensor semiconductor package 100 may cover second insulating layer 207. Moreover, the layer structure 200 is not limited to the number of layers shown in Figure 9 and additional layers may utilized to provide increased functionality. That is, the first insulating layer 203 may not be in direct contact with electrically conductive layer 205. Similarly, the second insulating layer 207 may not be in direct contact with electrically conductive layer 205. Referring to Figure 10, there is shown a view of the layer structure of Figure 9 in the direction of arrow “A”. In this view, the transfer layer 201 and the first insulating layer 203 are not shown so as to improve the visibility of the conductive layer 205. The conductive layer 205 comprises four separate conductive traces 205a - 205d. The four conductive traces 205a-205d are each connected to a different one of the external connection terminals 103 via connection points 211. In this way, four of the external connection terminals 103 are able to be electrically connected to other, separate, electronic components. The remainder of the external connection terminals 103 are not electrically connected to the conductive traces 205a-205d in this example. The external connection terminals 103 that are not electrically connected to the conductive traces 205a-205d may be redundant or may not be electrically connected to the semiconductor chip. These external connection terminals 103 may still be beneficially provide additional mechanical advantage to the sensor semiconductor package 100 and may help the sensor semiconductor package 100 remain in attachment with the rest of the layer structure. Referring to Figure 11 there is shown a cross-sectional view of an article 300 according to aspects of the present disclosure. The article 300 comprises a textile material 301 and a layer structure 200 as shown in Figures 9 and 10. The adhesive layer 209 of the layer structure 200 is attached to a surface of the textile material 301. The transfer layer is not present and has been removed to expose the electrode 117 of the sensor semiconductor package 100. In this way, the electrode 117 is able to approach or contact a skin surface of a user such as when the article 300 is worn. It will be appreciated that the relative thickness of the layers shown in Figures 9 to 11 is just for illustration purposes and may not reflect the actual thickness of the layers in the layer structure. Moreover, the thickness of the layer can be adapted by the skilled person based on factors such as the type of ink used and the number of printing operations performed. Referring to Figure 12, there is shown a schematic view of an example article 300 according to aspects of the present disclosure. The article 300 comprises a textile material 301. The article 300 further comprises an electronics module 303 and a layer structure 200 according to the present disclosure attached to the textile material 301. The layer structure 200 comprises a plurality (three in this example) of sensor semiconductor packages 100. Additionally, or separately, the article 200 may comprise the sensor semiconductor package 100’ of Figures 5 to 8. The three sensor semiconductor packages 100 are all electrically connected to the electrically conductive layer of the layer structure 200. The layer structure 200 in Figure 12 comprises a first conductive trace 205a and a second conductive trace 205b. A first external connection terminal of each of the sensor semiconductor packages is connected to the first conducive trace 205a. A second external connection terminal of each of the sensor semiconductor packages is connected to the second conductive trace 205b. The layer structure 200 comprises one or more openings in the first or second insulating layers to enable the electronics module 303 to electrically connect to the electrically conductive layer and thus electrically connect to the sensor semiconductor packages 100. The electronics module 303 may have one or more conductive studs or prongs to extend through the openings to contact the electrically conductive layer. Of course, other mechanisms for connecting an electronics module to an electrically conductive layer such as through the use of clips are within the scope of the present disclosure. The first conductive trace 205a is a bidirectional line for the article 300 which enables data to be transferred between the electronics module 303 and the sensor semiconductor packages 100. The bidirectional line 205a is a single-wire bidirectional line, and the semiconductor chip of the sensor semiconductor packages 100 send and / or receive data over the singe-wire bidirectional line using a single-wire communication protocol. The second conductive trace 205b is a return line for the article 200. The semiconductor chips of the semiconductor packages 100 are connected to ground by the return line. This arrangement enables a plurality of sensor semiconductor packages 100 to be connected to an electronics module 303 using a single wire bidirectional line 205a. This is the minimum possible number of conductive lines that may be provided. This reduces the number of physical hardware connections required for data transmission to / from the sensor semiconductor packages 100 and is particularly beneficial for wearable article implementations. It is appreciated that even with a single-wire protocol, a separate ground / return line 205b is still provided. This single-wire arrangement is particularly beneficial as it allows a number of sensor semiconductor packages 100 to be communicatively connected to one another and an electronics module 303 via a single conductive trace 205a in the layer structure. This simplifies the design, cost, and manufacture of the layer structure 200. The present disclosure is, however, not limited to singlewire bidirectional lines although particular advantages are achieved in these examples. Two-wire bidirectional lines, three-wire bidirectional lines or four or more wire bidirectional lines may also be used in some examples. The bidirectional lines may use any existing serial protocol such as Serial Peripheral Interface (SPI), Inter-Integrated Circuit (I2C), Controller Area Network (CAN), Recommended Standard 232 (RS-232), and 1-wire The electronics module 303 may be a removable electronics module 303 for the article 300. The electronics module 303 may be configured to be releasably mechanically coupled to the article 300. The mechanical coupling of the electronics module 303 to the article 300 may be provided by a mechanical interface such as a clip, a plug and socket arrangement, etc. The mechanical coupling or mechanical interface may be configured to maintain the electronics module 303 in a particular orientation with respect to the garment when the electronics module 303 is coupled to the article 300. This may be beneficial in ensuring that the electronics module 303 is securely held in place with respect to the article 300 and / or that any electronic coupling of the electronics module 303 and the article 300 (or a component of the article 300) can be optimized. The mechanical coupling may be maintained using friction or using a positively engaging mechanism, for example. It may be desirable to avoid direct contact of the electronics module 303 with the wearer’s skin while the article 300 is being worn. In particular, it may be desirable to avoid the electronics module 303 coming into contact with sweat or moisture on the wearer’s skin. The electronics module 303 may be provided with a waterproof coating or waterproof casing. For example, the electronics module 303 may be provided with a silicone casing. It may further be desirable to provide a pouch or pocket in the article 300 to contain the electronics module 303 in order to prevent chafing or rubbing and thereby improve comfort for the wearer. The pouch or pocket may be provided with a waterproof lining in order to prevent the electronics module 303 from coming into contact with moisture. The electronics module 303 may comprise a power source. The power source may comprise a plurality of power sources. The power source may be a battery. The battery may be a rechargeable battery. The battery may be a rechargeable battery adapted to be charged wirelessly such as by inductive charging. The power source may comprise an energy harvesting device. The energy harvesting device may be configured to generate electric power signals in response to kinetic events such as kinetic events performed by a wearer of the article 300. The kinetic event could include walking, running, exercising or respiration of the wearer. The energy harvesting material may comprise a piezoelectric material which generates electricity in response to mechanical deformation ofthe converter. The energy harvesting device may harvest energy from body heat of a wearer ofthe article 300. The energy harvesting device may be a thermoelectric energy harvesting device. The power source may be a super capacitor, or an energy cell. The electronics module 303 may comprise a communicator. The communicator may be a mobile / cellular communicator operable to communicate the data wirelessly via one or more base stations. The communicator may provide wireless communication capabilities for the article 300 and enables the article 300 to communicate via one or more wireless communication protocols such as used for communication on: a wireless wide area network (WWAN), a wireless metroarea network (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN), a near field communication (NFC), and a cellular communication network. The cellular communication network may be a fourth generation (4G) LTE, LTE Advanced (LTE-A), fifth generation (5G), sixth generation (6G), and / or any other present orfuture developed cellular wireless network. A first communicator of the electronics module 303 may be provided for cellular communication and a separate communicator may be provided for short-range local communication over WLAN, WPAN, NFC, or Bluetooth ®, WiFi or any other electromagnetic RF communication protocol. The electronics module 303 may comprise a Universal Integrated Circuit Card (UICC) that enables the wearable article to access services provided by a mobile network operator (MNO). The UICC may include at least a read-only memory (ROM) configured to store an MNO profile that the wearable article can utilize to register and interact with an MNO. The UICC may be in the form of a Subscriber Identity Module (SIM) card. The wearable article may have a receiving section arranged to receive the SIM card. In other examples, the UICC is embedded directly into a controller of the wearable article. That is, the UICC may be an electronic / embedded UICC (eUlCC). A eUlCC is beneficial as it removes the need to store a number of MNO profiles, i.e. electronic Subscriber Identity Modules (eSIMs). Moreover, eSIMs can be remotely provisioned. The article 200, 200’ may comprise a secure element that represents an embedded Universal Integrated Circuit Card (eUlCC). Referring to Figure 13, there is shown an example article 300 according to aspects of the present disclosure worn by a user 400. The article 300 in this example is a garment and, in particular, comprises a textile material 301 which forms a T-shirt. The article 300 further comprises an electronics module 303 and a layer structure 200 comprising a plurality (three in this example) of sensor semiconductor packages 100. The sensor semiconductor packages 100 are connected to the electronics module 303 via the conductive traces of the layer structure 200. The sensor semiconductor packages 100 are provided on the inside surface of the textile material 301 and are not visible externally. The sensor semiconductor packages 100 are positioned such that their electrodes are able to contact the skin. Referring to Figure 14, there is shown a process flow diagram for an example method according to aspects of the present disclosure of manufacturing a layer structure. The method uses a transfer printing process to form the layer structure. The transfer printing process may be a screen printing process, reel-to-reel printing, dot matrix printing, laser printing, cylinder press printing, inkjet printing, flexographic printing, lithographic printing, offset printing, digital printing, gravure printing or xerographic printing, or other known printing process. Step S101 of the method comprises printing non-conductive ink onto a transfer layer to produce a first insulating layer. Step S102 of the method comprises printing an electrically conductive ink onto said first non-conductive printed ink layer to produce an electrically conductive layer. Step S103 of the method comprises providing a sensor semiconductor package according to the present disclosure such as the sensor semiconductor package of any of Figures 1 to 8. Step S104 of the method comprises positioning the sensor semiconductor package on the electrically conductive layer such that the electrically conductive layer is electrically connected to the first and second external connection terminals. Step S105 of the method comprises printing non-conductive ink over said electrically conductive layer to produce a second insulating layer. The first insulating layer may be cured prior to the step of printing the electrically conductive layer. The electrically conductive layer may be cured prior to the steps of positioning the sensor semiconductor package on the electrically conductive layer and printing the second insulating layer. In some examples, however, the sensor semiconductor package is positioned on the electrically conductive layer before the electrically conductive layer is cured. Curing may involve drying the layer. Following the production of the second insulating layer, the method may further comprise applying an adhesive over the second insulating layer to produce an adhesive layer. The adhesive layer may be printed or otherwise applied to the second insulating layer. The adhesive layer may be applied before or after the second insulating layer is cured depending on factors such as the type of adhesive used. In an example method of manufacturing an article, a layer structure as manufacture d in the method of Figure 14 is attached to a surface of the article using the adhesive layer. The transfer layer is then removed. Referring to Figure 15, there is shown a process flow diagram for an example method according to aspects of the present disclosure of manufacturing a sensor semiconductor package. Step S201 of the method comprises providing at least one die pad and a plurality of external connection terminals. Step S202 of the method comprises providing a semiconductor chip. Step S203 of the method comprises locating the semiconductor chip on a top surface of the at least one die pad. Step S204 of the method comprises electrically connecting the semiconductor chip to the plurality of external connection terminals and the at least one die pad. Step S205 of the method comprises forming a sealing member covering the die pad, the plurality of external connection terminals and the semiconductor surface and exposing an outer terminal of each of the plurality of external connection terminals and an outer contact surface of the at least one die pad, wherein the outer contact surface of the at least one die pad forms an electrode of the sensor semiconductor package. Providing the at least one die pad and a plurality of external connection terminals may comprise providing a lead frame including the at least one die pad and the plurality of external connection terminals. In some examples, the lead frame comprises a plurality of regions to be separated from one another to provide a plurality of sensor semiconductor packages. Each of the plurality of region comprises at least one die pad and a plurality of external connection terminals. For each of the regions, a semiconductor chip is located on a top surface of the at least one die pad, and the semiconductor chip is electrically connected to the plurality of external connection terminals and the at least one die pad. For each of the regions, a sealing member is then formed covering the die pad, the plurality of external connection terminals and the semiconductor surface and exposing an outer terminal of each of the plurality of external connection terminals and an outer contact surface of the at least one die pad, wherein the outer contact surface of the at least one die pad forms an electrode of the sensor semiconductor package. The plurality of regions may then be separated from one another to form the plurality of semiconductor packages. The sensor semiconductor package according to aspects of the present disclosure is therefore manufactured using existing, established, semiconductor package manufacturing techniques. The additional step of electrically connecting the die pad to the semiconductor chip does not overly complicate the semiconductor package manufacturing process compared to conventional arrangements as this step can be performed using existing techniques already used for connecting the semiconductor chip to the external connection terminals (e.g. wire bonding). The manufacturing techniques enables many sensor semiconductor packages to be manufactured at the same time. Therefore, aspects of the present disclosure facilitate the rapid, and low cost, manufacture of sensor semiconductor packages. In some examples of the present disclosure, the sensor semiconductor package has a QFN-type structure (Quad Flat Non-lead Package). The present disclosure is not limited to QFN-type structures and could, for example, be any type of surface-mount package. Other example packages include Quad Flat Packages (QFP), and Ball Grid Array (BGA) packages. The sensor semiconductor package is not limited to only one semiconductor chip and may include at least one semiconductor chip. In some examples, the sensor semiconductor package comprises a plurality of semiconductor chips. Each of the plurality of semiconductor chips may be electrically connected to a different die pad of the sensor semiconductor package. The sensor semiconductor package may be used for sensing any kind of signal which requires the use of an electrode. In preferred examples, the sensor semiconductor package is biosensor semiconductor package and the electrode(s) of the biosensor semiconductor package arefor monitoring a biosignal of a living body. The biosignal may be a bioelectrical signal or a bioimpedance signal for example. Particular examples include the biosensor semiconductor package being an electrocardiography (ECG) semiconductor sensor package and / or an electromyography semiconductor (EMG) semiconductor sensor package. The sensor semiconductor package in accordance with the present disclosure may have any size as appropriately selected by the skilled person in the art. The sensor semiconductor package may have a width of less than or equal to 10 mm, preferably less than or equal to 6 mm. The sensor semiconductor package may have a length of less than or equal to 10 mm, preferably less than or equal to 6 mm. The sensor semiconductor package may have a width of greater than or equal to 3 mm, preferably greater than or equal to 4 mm. The sensor semiconductor package may have a width x length of between 3 mm x 3 mm and 10 mm x 10 mm, preferably between 4 mm x4 mm and 6 mmx6 mm. The size of the sensor semiconductor package may depend on factors such as the number of external connection terminals and the size of the semiconductor chip. Generally, a sensor semiconductor package having 24 external connection terminals will have a width x length of 4 mm x 4 mm. At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as ‘component’, ‘module’ or‘unit’ used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the components) specified but not to the exclusion of the presence of others. All of the features disclosed in this specification (including any accompanying claims, abstract 5 and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and 10 drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s). The invention 15 extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

20 01 251. A layer structure for application to a surface, the layer structure comprising:a first non-conductive printed ink layer;5 a second non-conductive printed ink layer;an electrically conductive printed ink layer positioned between the first non-conductive printed ink layer and the second non-conductive printed ink layer;a sensor semiconductor package provided on the electrically conductive printed ink layer, the sensor semiconductor package comprising:10 a first external connection terminal electrically connected to the electricallyconductive printed ink layer;a second external connection terminal electrically connected to the electrically conductive printed ink layer;a semiconductor chip electrically connected to the first external connection terminal15 and the second external connection terminal; anda sealing member covering the first and second external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals.20 2. A layer structure as claimed in claim 1, further comprises a transfer layer, wherein thefirst non-conductive printed ink layer is provided on the transfer layer.

3. A layer structure as claimed in claim 1 or 2, further comprising comprises an adhesive layer, and wherein the adhesive layer is provided on the second non-conductive printed 25 ink layer.

4. A layer structure as claimed in any preceding claim, wherein the sensor semiconductor package further comprises a die pad, the semiconductor chip is located on a top surface of the die pad, and the sealing member covers the die pad and exposes an outer contact 30 surface of the die pad, and wherein the first non-conductive printed ink layer comprisesan opening aligned with the outer contact surface of the die pad such that at least part of the outer contact surface of the die pad is not covered by the first non-conductive printed ink layer.35 5. A layer structure as claimed in claim 4, wherein the electrically conductive printed inklayer comprises an opening aligned with the outer contact surface of the die pad such that at least part of the outer contact surface of the die pad is not covered by the electrically conductive printed ink layer.20 01 256. A layer structure as claimed in claim 4 or 5, wherein the semiconductor chip is electrically connected to the die pad, and the outer contact surface of the die pad forms an electrode of the sensor semiconductor package.5 7. A layer structure as claimed in claim 6, wherein at least one wire extends from thesemiconductor chip to connect the semiconductor chip to the at least one die pad, and wherein a plurality of wires extend from the semiconductor chip to connect the semiconductor chip to the plurality of external connection terminals.10 8. A layer structure as claimed in any of claims 4 to 7, wherein the semiconductor chip isarranged to receive a measurement signal from the die pad.

9. A layer structure as claimed in any of claims 4 to 8, wherein the semiconductor chip is attached to the top surface of the at least one die pad by an adhesive.1510. A layer structure as claimed in any preceding claim, wherein the electrically conductive printed ink layer comprises a first conductive trace and a second conductive trace, and wherein the first conductive trace is electrically connected to the first external connection terminal, and wherein the second conductive trace is electrically connected to the 20 second external connection terminal.

11. A layer structure as claimed in claim 10, wherein the first conductive trace is a bidirectional line for an article, and wherein the semiconductor chip of the sensor semiconductor package is arranged to send and / or receive data over the bidirectional 25 line.

12. A layer structure as claimed in claim 11, wherein the bidirectional line is a single-wire bidirectional line, and wherein the semiconductor chip of the sensor semiconductor package sends and / or receives data over the singe-wire bidirectional line using a single-30 wire communication protocol.

13. A layer structure as claimed in any of claims 10 to 12, wherein the second conductive trace is a return line for the article, and wherein the semiconductor chip of the sensor semiconductor package is connected to ground via the return line.3514. A layer structure as claimed in any preceding claim, wherein the sensor semiconductor package is a first sensor semiconductor package, and wherein the layer structure further comprises a second sensor semiconductor package, the second sensor semiconductor package comprising: a first external connection terminal; a second external connection20 01 25terminal; a semiconductor chip electrically connected to the first external connection terminal and the second external connection terminal; and a sealing member covering the first and second external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals.

515. A layer structure as claimed in claim 14, wherein the second sensor semiconductor package is provided on the electrically conductive printed ink layer, and wherein the first and second external connection terminals of the second sensor semiconductor package are electrically connected to the conductive printed ink layer.1016. An article comprising the layer structure as claimed in any preceding claim, wherein the layer structure is attached to a surface of the article.

17. An article as claimed in claim 16, further comprising an electronics module, the 15 electronics module comprising a power source, a processor and a memory, wherein theelectronics module is arranged to be electrically connected to the electrically conductive printed ink layer of the layer structure and is further arranged to communicate with the sensor semiconductor package via the electrically conductive printed ink layer.20 18. An article as claimed in claim 17, wherein the electronics module is removable from thearticle, optionally wherein the article comprises an electronics module holder for at least temporarily holding the electronics module.

19. An article as claimed in any of claims 16 to 18, wherein the article is a wearable article, 25 optionally wherein the wearable article is a garment.

20. An article as claimed in any of claims 16 to 19, wherein the sensor semiconductor package is a biosensor semiconductor package for monitoring a biosignal of a living body.3021. A method for manufacturing a layer structure, the method comprisingprinting non-conductive ink onto a transfer layer to produce a first non-conductive printed ink layer;printing an electrically conductive ink onto said first non-conductive printed ink layer to 35 produce an electrically conductive printed ink layer;providing a sensor semiconductor package, wherein the sensor semiconductor package comprises: a first external connection terminal; a second external connection terminal; a semiconductor chip electrically connected to the first external connection terminal and the second external connection terminal; and a sealing member covering the first andsecond external connection terminals and the semiconductor chip and exposing an outer terminal of each of the first and second external connection terminals;positioning the sensor semiconductor package on the electrically conductive printed ink layer such that the electrically conductive printed ink layer is electrically connected to 5 the first and second external connection terminals;printing non-conductive ink over said electrically conductive layer to produce a second non-conductive printed ink layer.

22. A method as claimed in claim 21, further comprising applying an adhesive over the 10 second non-conductive printed ink layer to produce an adhesive layer.

23. A method for manufacturing an article, the method comprising: providing a layer structure as claimed in any of claims 1 to 15; and attaching the layer structure to a surface of the article.20 01 25

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