Patent Application
20210096156
The present invention concerns the technical field of electronic components in general and in particular the electronic devices, such as the socket, which are used in order to test other electronic components.
Therefore, the invention refers to an innovative heating assembly which allows to carry out temperature-dependent tests on electronic components arranged in the suitable socket in easy and versatile manner, in particular for testing BGA components.
The socket is a known testing device to test other electronic components (the so-called DUT “Device Under Test”). In particular, the “socket” is a sort of cradle which is fixed to a printed circuit board, named with the acronym P.C.B, that is Printed Circuit Board. Such a cradle of the socket has electrical contacts communicating with the P.C.B. and it is made in such a manner as to form a housing in which the electric component to be tested is arranged (a DUT, such as a further printed circuit board or a processor). The housing is equipped with other electric contracts connecting with the component to be tested (DUT) in such a manner that the signal emitted by the P.C.B. can be transferred to the component to be tested by means of the socket on which the component is arranged. The P.C.B. sends all the electric signals necessary for the test and in this manner, the correct operation of the electronic component occurs, depending on the kind of test to be carried out.
It is known that many standard tests have to be carried out at predetermined temperatures, which are well above the room temperature (for example around 130° C.) and such a temperature has to be maintained for a predetermined number of hours.
For this purpose, suitable cabinets are known in the state of the art, acting as ovens and then equipped with suitable heating system. The various sockets, on which the components to be tested have to be arranged, are arranged in such cabinets.
It is obvious that such an embodiment is particularly complex and expensive, as it requires bulky heating structures with expensive maintenance costs.
In order to overcome such a technical inconvenience, the same applicant filed a previous European patent application EP3173798 which discloses a new, compact, efficient and cheap heating device. The publication EP3173798 is to be considered fully incorporated by reference in the present description.
Such a publication discloses a heating device in the form of a conductive multi-layer with resistances incised directly on the conductive layers, and through which a heating is obtained for Joule effect.
Therefore, the shape of the device is a tablet formed by many layers, suitably applied to the housing of the socket below the component to be tested. A voltage is applied and the passage of current in the incised resistances allows the heat production for Joule effect.
Nevertheless, such an embodiment cannot be applied inside sockets destined to test BGA components (acronym for Ball Grid Array). In fact, in this case, the structure of the BGA has an array of contacts which covers almost its whole surface and the socket is equipped with a numerous succession of metallic needles which form the pins of electric contact engaged with the array of contacts of the BGA on one side and with the contacts of the P.C.B. on the opposite side.
In this manner, such a structure of the socket and the BGA component to be inserted in the socket has no suitable area for applying the heating device described in such a European application directly below the component to be tested inside the socket.
Substantially, the overall structure of the heating device described in the previous patent application is not specifically suitable for such an application and therefore, it cannot be used.
It is therefore the aim of the present invention to furnish a heating assembly (10, 15) which solves at least in part all the above-mentioned technical inconveniences.
In particular, the aim of the present invention is to furnish a heating assembly (10, 15) which can be applied to any socket, and in particular to those destined to test BGA, in a suitable position to carry out a test at a predetermined temperature.
The aim of the present invention is also to furnish a heating assembly (10, 15) easily, cheaply and functionally allowing to carry out temperature-dependent tests on any socket and in particular on the BGA device as it is inserted in its suitable socket.
Therefore, these and other aims are achieved with the present heating assembly (10, 15) for generating heat and carrying out temperature-dependent tests on an electronic component (3, 200) inside a socket (2), according to claim 1.
Such a heating device (10, 15) comprises:
In this manner, all the above-mentioned technical inconveniences are easily solved.
In particular, thanks to the adiabatic covering 15, the heating device inside the covering can produce heat which is directed outwardly through the passage obtained in the covering itself. Therefore, as the covering with the heating device inside is applied to a support surface which forms the printed circuit board for the tests, the whole assembly, formed by covering and heating device, can be arranged outwards the socket in a convenient position such that the heat flow hits the socket with the component 3 to be tested inside it.
In this manner, it is formed an environment with controlled temperature with no need to apply the single heating device in the socket but instead by suitably applying it outside the socket in a convenient position.
Therefore, the adiabatic container acts not only as support to apply the heating device 10 outside the socket, but, moreover, it forms an adiabatic barrier which limits the heat dispersion, by directing the heat flow towards the socket.
Advantageously, such fastening means are of the removable type in such a manner that said heating assembly (10, 15) can be applied to said support surface (5B) in removable manner.
Advantageously, said passage area can be in the form of at least an opening obtained in the covering.
Advantageously, a layer of thermally conductive material applied to the passage area of said opening of the covering can be further comprised in order to facilitate the heat transfer.
More precisely, said layer of thermally conductive material is arranged on a surface of the heating device (10) in such a manner as to obstruct at least in part said opening for the passage of heat such that said layer is interposed between the support surface (5B), to which the heating assembly is applied while used, and the surface of the device (10) which faces said area for the passage of heat.
Advantageously, said heating assembly (10) is in form of a multi-layer.
In this manner, the sizes are compact.
Advantageously, the multi-layer comprises one or more layers of electrically conductive material and wherein the layer of electrically conductive material (25) is insulated from a further layer of electrically conductive material (25) by means of the interposition of a layer of insulating material (30), at least one or more of said layers of electrically conductive material comprising a resistance (33) for the passage of current.
Advantageously, said resistance (33) is in the form of an incision obtained directly on the layer of electrically conductive material (25).
Such an embodiment helps to compact the sizes.
Advantageously, the container (15) is made at least in part of thermally insulating materials, such as:
Such materials are not to be considered limiting and other thermally insulating materials, also with different insulating degrees, can be equally used without going beyond the scope of the present invention.
Here it is also disclosed a printed circuit board (5) comprising an upper surface (5A) on which a socket (1) is arranged, preferably a socket for testing a component (3) of BGA type, a lower surface (5B) and a plurality of electric contacts for transmitting the electric signal to said socket (1).
According to the invention, the printed circuit board (5) comprises a heating assembly (10, 15) as disclosed above, applied in fixed or removable manner.
Moreover, advantageously, said heating assembly is applied on the surface (5B), substantially inside the area delimiting the housing of said array of electrical connections, in such a manner as to be in axis below the socket.
Further features and advantages of the present heating assembly (10, 15), will become apparent from the following description of preferred embodiments thereof, given only by way of non-limiting, indicative, example, with reference to the accompanying drawings, wherein:
Figures from 3 to 5 depict a constructive detail of the heating device already described in the previous European application EP3173798, fully incorporated by reference here; in particular
In particular, number 5 indicates the printed circuit board P.C.B., having an upper surface 5A and a lower surface 5B.
The socket is applied on the upper surface 5A, having a structure 2 which forms a cradle 2A in which is inserted the component 3 to be tested, in particular the component BGA 3 formed, as it is well inferable from
Such arrays of contacts 3B, as better highlighted in the enlarged view of
In this manner, according to the known art, it is possible to test the component 3, by sending suitable electric signals of tests which start from the P.C.B.
As it is inferable from
It could be potentially arranged inside the cradle 2A above the component 3 but this arrangement would be useless as the heat flow would go upwards without hitting the component 3.
Therefore, there is the need to easily apply a heating device substantially as the one disclosed in the reference application EP3173798.
For solving the issue, it has been realized an assembly (10, 15) which can be applied externally, and in particular below the socket.
This assembly is formed by a container 15 (or also covering) which contains the heating device 10 inside.
The container (or covering) is made of thermally insulating material and is configured to be applicable, in removable manner, to the side 5B of the P.C.B., therefore on the opposite side with respect to that where the socket is fastened.
The container can have a simple box-like shape so as to form a housing in which to arrange the device 10.
As can be inferred from
The container 15 is obviously open by a part thereof so that, as depicted in
In this manner, the heat produced by the device can freely radiate upwards and therefore towards the overlying socket and towards the component 3 to be tested but the heat is prevented from dispersing downwards and laterally, thanks to the insulating walls forming the container itself.
Therefore, this system allows an easy application to any printed circuit board P.C.B. by making the heat flow converging towards the component to be tested.
The container can be made of various thermally insulating materials.
In a non-limiting way, for example, it is possible to cite materials such as plastic, Teflon plastic, PEEK or aerogel which is a silica gel containing micro-bubbles of air. Other usable thermally insulating materials can be, for example, silicone foam.
Common materials internally or externally coated with materials with thermally insulating properties can also be used.
Therefore, the box-shaped container is provided with lateral walls 15L and a lower wall 15I and is open on the opposite side to the wall 15I, so that the heating device 10 can contact the wall 5B and radiate heat from this opening.
The walls are obviously continuous to avoid the heat dispersion and therefore do not have significant openings or openings that imply a dispersion of heat.
In this manner, the housing formed by these walls does not dissipate heat.
The power supply for the heating device 10 occurs by connecting or welding the upper surface, that is the P.C.B. 5.
For example, the thermally insulating container can generally be box-shaped, of rectangular or quadrangular, in such a manner as to retrace the shape of the heating device 10 which is containing.
Obviously, other box-shaped containers, such as cylindrical, can be realized.
Preferably, the container 10 is equipped with some lateral flanges, which extend radially from the lateral walls 15L (see for example
Experimental evidence proves that a layer or a sheet of thermally conductive material can be interposed between the surface 5B and the heating device 10 in such a way that the heating device does not touch such a surface 5B directly.
Substantially, a thin layer of thermally conductive material can be interposed between the surface 5B and the surface of the device 10. It remarkably favours the heat diffusion upwards, that is towards the device to be tested, thus optimizing further the heat flow and thermal conditions for carrying out the test.
For example, a material that can be used for realizing such a thermally conductive sheet can be a material with the trademark “Berquist Gap Pad 5000 s35”, brand name Henkel.
Even if the above-mentioned material proved to be suitable for the purposes, other thermally conductive material can be used without however moving away from the scope of the present invention.
The heating device 10 contained inside the container 15 is substantially those one described in the application EP3173798 and described below for clarity purposes.
Such a heating device is equipped with at least a resistance through which electric current passes, such that it is heated for Joule effect and therefore produces the heat necessary for heating the component to be tested.
By suitably adjusting the passage of current, the required temperature can be easily obtained and controlled.
In more details, as depicted in the section of
Therefore, it is in the form of a multi-layer.
In particular, conductive layers 25 are provided, preferably of metallic material such as copper, interposed to insulating layers 30, preferably polyamide.
The purpose of the insulating layer is to prevent said conductive layers from short-circuiting each other, thus insulating from each other.
Therefore, each layer forms a surface of predetermined thickness and interposed each other as per section of
Any shape can be provided, such as square, rectangular or circular metal tablet.
The thicknesses are reduced, approximately a millimeter as a whole.
As highlighted in the section of
The resistance is preferably obtained by removing and then carving the layer according to the required geometry (generally a sort of wavy line).
The first and the last conductive layer are preferably covered or gold-plated for protecting them from corrosion. Preferably, but not necessarily, the resistance is not obtained on them and their purpose, as they are metallic, is to better give off the heat outwards.
The realization of resistances by means of an incision of a track directly on the surface of the conductive material (therefore, by removing the material) has the great advantage of making the device more compact with a particularly simple productive process, contrary to an embodiment where the track is obtained by pouring a conductive material which generates an increase of thickness.
A plurality of micro holes passing through the whole thickness of the device 10 are then provided. Such micro-holes are preferably covered by metal inside and their purpose is to favour the heat diffusion further. In this manner, the heat radiates towards the overlying component to be tested in more efficient manner (see for example
As depicted in
Moreover, in order to pass current through all the layers equipped with track, they are connected each other by means of one or more ducts 32, in which an electric cable passes and physically connects all the copper layers for injecting the voltage of the passage of current.
The advantage of realizing a multi-layer element is that it is possible to maintain extremely reduced sizes and obtain a high heat at the same time. In fact, a track for the passage of current can be obtained on each layer. Therefore, the more layers there are, the greater the heat produced, thus maintaining at the same time reduced encumbrances (the structure increases its height but not its width).
Therefore, such a device can be miniaturized at will.
Moreover, the realization of incised tracks further contributes to reduce thicknesses.
Moreover, it is possible to equip one of the conductive layers, preferably one of the two external ones, a contact with an electric wiring connectable to an external control device (for example a PC). In this manner, it is easy to monitor the reached temperature and adjust and vary it depending on needs, by increasing or reducing the passage of current.
Such an assembly (10, 15) can be an independent component, therefore produced and sold independently and easily applicable to any printed circuit board P.C.B. for testing components 3 by means of the above-mentioned rapid fastening means, such as feed screws or trip systems.
Alternatively, it can be already in-built in the P.C.B. or in a socket for carrying out such tests.
While in use, therefore, it is sufficient to apply such a heating assembly (10, 15) on the lower surface 5B of the circuit board P.C.B. 5, that is below the socket, and inject current to produce heat.
The thermally insulating box will manage the heat diffusion towards the socket and therefore towards the component 3 to be tested.
The interposition of a thermally conductive layer favours further the heat diffusion towards the component to be tested.
Even if the present invention is preferably intended for testing BGA components, its use as described is not excluded for testing any component 200 arranged inside a socket, even if there is sufficient space to insert directly in the socket the device 10 below the component to be tested.
Therefore, its applicability outwards allows the sizes of the heating device 10 not to be necessarily bound to the size 2A of the housing of the socket, thus making the system very versatile.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102017000121768 | Oct 2017 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2018/057916 | 10/12/2018 | WO | 00 |
