TWM581353U - Printed circuit board stack structure - Google Patents

Abstract

A printed circuit board (PCB) stack structure includes a first PCB, a second PCB, a connector and a protection frame. The first PCB includes a first pad. The second PCB includes a second pad. The connector is disposed between the first PCB and the second PCB, and connected to the first PCB and the second PCB through a separable fastener. The connector includes a substrate, a first conductive elastic piece and a second conductive elastic piece. The substrate has a first surface and a second surface opposite to each other. The first conductive elastic piece is located on the first surface and in contact with the first pad. The second conductive elastic piece is located on the second surface and in contact with the second pad. The protection frame is disposed side by side with the connector, and between the first PCB and the second PCB.

Description

Printed circuit board stack structure

The novel creation is related to a printed circuit board stack structure.

In order to reduce the area occupied by a printed circuit board in an electronic product (for example, a mobile phone, a computer, etc.), the prior art divides a printed circuit board into two pieces and interposes two printed circuit boards with each other by an interposer. Connected to form a printed circuit board stack structure. In general, the interposer is a ball grid array (BGA) interposer and has solder balls disposed on opposite surfaces thereof. The printed circuit boards are soldered to the opposite surfaces of the interposer by solder balls via two surface mounting technologies (SMT), thereby electrically connecting the printed circuit boards to each other by the interposer. However, in the above SMT process, the high temperature tin furnace may damage the integrated circuit (IC) parts on the printed circuit board or cause the printed circuit board to warp and deform due to thermal stress.

On the other hand, the interposer is difficult to separate from each other after solder balls are soldered to the printed circuit board. If the components in the subsequent printed circuit board stack structure fail, the product is defective, which is not conducive to disassembling the stack structure. repair.

The present invention provides a printed circuit board stack structure in which the connectors in the printed circuit board stack structure are designed with a spring piece and have conductive elastic sheets on opposite surfaces thereof to electrically connect the printed circuit boards. The printed circuit board and the connector are fixed together in a detachable assembly. In this way, the SMT process can be omitted, avoiding the problems caused by the SMT process. In addition, the detachable assembly method can facilitate the repair of the product. The printed circuit board stack structure created by the present invention can be applied to electronic products such as mobile phones and computers.

The invention creates a printed circuit board stack structure comprising a first printed circuit board, a second printed circuit board, a connector and a protective frame. The first printed circuit board includes a first pad. The second printed circuit board includes a second pad. The connector is disposed between the first printed circuit board and the second printed circuit board, and is connected to the first printed circuit board and the second printed circuit board by the detachable fastener. The connector includes a substrate, a first conductive elastic piece and a second conductive elastic piece. The substrate has a first surface and a second surface opposite to each other. The first conductive elastic piece is located on the first surface and is in contact with the first pad. The second conductive elastic piece is located on the second surface and is in contact with the second pad. The protective frame and the connector are disposed side by side between the first printed circuit board and the second printed circuit board.

Based on the above, the present invention electrically connects different printed circuit boards to each other by a connector having conductive springs, and uses a detachable fastener to secure the printed circuit board and the connector together. In this way, compared with the traditional way of using BGA/BGA interposer to solder the printed circuit board, the new creation omits two SMT processes, avoiding or reducing the soldered parts on the printed circuit board caused by the high temperature tin furnace. Damage or warpage of the printed circuit board. In addition, since the printed circuit board and the connector of the present invention are detachably assembled by separable fasteners, the printed circuit board can be easily stacked if components in the printed circuit board stack fail. The structure is disassembled for easy repair.

The above described features and advantages of the present invention will become more apparent and understood from the following description.

The present invention will be described more fully with reference to the drawings of the present embodiment. However, the novel creations can also be embodied in a variety of different forms and should not be limited to the embodiments described herein. The same or similar component numbers indicate the same or similar components, and the following paragraphs will not be repeated.

Referring to FIG. 1, in some embodiments, printed circuit board stack 500 includes printed circuit board 300, connector 100, protective frame 150, printed circuit board 200, and mounting plate 400. At least one connector 100 is located between the printed circuit board 200 and the printed circuit board 300 to electrically connect the printed circuit board 200 and the printed circuit board 300 to each other. In some embodiments, the connector 100 and the printed circuit boards 200 and 300 are connected and secured together by separable fasteners. The separable fastener includes a keeper, a snap, a screw element, the like, or a combination thereof. For example, the locating members include locating posts 108a and 108b on the connector 100 and locating holes 208 and 308 on the printed circuit boards 200 and 300. The protective frame 150 is disposed side by side with the connector 100 between the printed circuit board 200 and the printed circuit board 300 for protecting components of the printed circuit board and shielding electromagnetic interference generated by the components.

Referring to FIGS. 1 and 3A, in the inventive embodiment, the connector 100 includes a substrate 101, a conductive terminal 102, a conductive terminal 103, a through via 104, a positioning post 108a, and a positioning post 108b. The substrate 101 is an insulating substrate, for example, an FR4 substrate, but the present invention is not limited thereto. The substrate 101 has a first surface (for example, a top surface) 101a and a second surface (for example, a bottom surface) 101b opposed to each other. The conductive terminals 102 and the conductive terminals 103 are respectively disposed on the first surface 101a and the second surface 101b of the substrate 101, and are electrically connected to each other by the through holes 104. Conductive terminals 102 and 103 comprise a conductive material such as a metal or metal alloy. For example, conductive terminals 102 and 103 can comprise copper, a copper alloy, or the like. In some embodiments, the connector 100 is a land grid array (LGA) connector (or LGA/LGA connector), but the invention is not limited thereto.

In some embodiments, the conductive terminals 102 and 103 are conductive springs or conductive elastic cantilevers. For example, the conductive terminal 102 includes a fixed portion 102a and a free portion 102b that are connected to each other. The fixing portion 102a is fixed to the top surface 101a of the substrate 101 and/or the top surface of the through hole 104, and is in contact with the through hole 104 and/or the first surface 101a of the substrate 101. The free portion 102b is suspended above the first surface 101a of the substrate 101 without being in contact with the first surface 101a and the through hole 104. The conductive terminal 103 includes a fixing portion 103a and a free portion 103b that are connected to each other. The fixing portion 103a is fixed on the bottom surface of the second surface 101b and/or the through hole 104 of the substrate 101, and is in contact with the second surface 101b of the through hole 104 and/or the substrate 101, and the free portion 103b is suspended below the second surface 101b of the substrate 101. Without contacting the second surface 101b and the perforations 104. It should be noted that FIG. 3A is a state in which the connector 100 has not been fixed to the printed circuit board.

In some embodiments, for example, as shown in FIG. 3A, the conductive terminal 102 and the conductive terminal 103 are symmetrically disposed with respect to the substrate 101, and the free portion 102b of the conductive terminal 102 and the free portion 103b of the conductive terminal 103 extend in the same direction, but The disclosure is not limited to this. In other embodiments, for example, as shown in FIG. 4, the conductive terminal 102 and the conductive terminal 103 are asymmetrically disposed with respect to the substrate 101, and the free portion 102b of the conductive terminal 102 and the free portion 103b of the conductive terminal 103 face in different directions, for example, It is the opposite direction. The projections of the conductive terminals 102 and the conductive terminals 103 on the first surface 101a or the second surface 101b of the substrate 101 may overlap each other, for example, completely overlapping or partially overlapping. It should be noted that the conductive terminals 102 and 103 in the cross-sectional view 3A are shown to extend in a direction parallel to the longitudinal direction of the connector 100 for the sake of clarity and ease of explanation, but the disclosure is not limited thereto. It should be understood that the conductive terminals 102 and 103 may each be configured to extend in any suitable direction depending on the locations of the pads 202 (Fig. 3B) and 302 disposed in the printed circuit boards 200 and 300, respectively, corresponding to the conductive terminals 102 and 103, respectively. .

With continued reference to FIGS. 1 and 3A, the vias 104 are embedded in the substrate 101 and are located between the conductive terminals 102 and the conductive terminals 103. In some embodiments, the top surface of the aperture 104 is substantially flush with the first surface 101a of the substrate 101, and the bottom surface of the aperture 104 is substantially flush with the second surface 101b of the substrate 101. The through holes 104 pass through the substrate 101 to electrically connect the conductive terminals 102 and the conductive terminals 103 on the opposite surfaces of the substrate 101 to each other. The perforations 104 comprise a conductive material such as a metal or metal alloy. For example, the perforations 104 can include copper, copper alloys, or the like.

In some embodiments, each of the vias 104 connects a set of conductive terminals 102 and 103 that correspond to each other. The corresponding set of conductive terminals 102 and 103 and the through holes 104 therebetween form a connector 107. In other words, the connector 100 includes a plurality of connectors 107. In some embodiments, the plurality of connectors 107 are spaced apart from each other and electrically isolated. The plurality of connectors 107 may include connectors, ground connectors, and/or dummy connectors for electrically connecting the printed circuit boards 200 and 300 and for transmitting signals, but the present invention is not limited thereto.

The positioning post 108a is disposed on the first surface 101a of the substrate 101, and the positioning post 108b is disposed on the second surface 101b of the substrate 101. In some embodiments, the positioning post 108a and the positioning post 108b are aligned with each other in a direction perpendicular to the first surface 101a or the second surface 101b of the substrate 101, but the disclosure is not limited thereto. The positioning post 108a and the positioning post 108b may also be arranged in a staggered manner.

Referring to Figures 1, 2A, 3B and 3C, a printed circuit board 300 is provided. The shape of the printed circuit board 300 may be a regular shape such as a square, a rectangle, a polygon, or the like, or other irregular shape. Printed circuit board 300 can have any suitable shape depending on product design and needs.

The printed circuit board 300 includes pads 302, solder joints 350, and locating holes 308. The pad 302 is disposed on the top surface 301a of the printed circuit board 300 opposite to the connector 100 for electrically connecting to the connector 100. The pad 302 includes a conductor material such as a metal or a metal alloy. For example, the pads 302 can comprise copper, aluminum, alloys thereof, or the like. A plurality of solder joints 350 are disposed on the top surface 301a of the printed circuit board 300 for soldering the protective frame 150. A plurality of solder joints 350 are annularly disposed and enclose an annular region R. Herein, the ring shape includes a regular ring shape such as a square ring, a circular ring, an elliptical ring, or the like, or an irregular ring shape. The pad 302 is disposed, for example, outside the annular region R surrounded by the solder joints 350. In some embodiments, the two sets of pads 302 are disposed on both sides of the annular region R, but the disclosure is not limited thereto. The positioning hole 308 passes through the printed circuit board 300 and is disposed at a position corresponding to the positioning post 108b of the connector 100.

In some embodiments, printed circuit board 300 includes a plurality of components 305 disposed on a top surface 301a thereof, such as integrated circuit wafers and the like. Element 305 can include an active element, a passive element, or a combination thereof. The active element includes, for example, a transistor, a diode, or the like. Passive components include, for example, capacitors, resistors, inductors, and the like. The dimensions of the plurality of elements 305 may be the same or different from one another and may be the same type or different types of elements. In some embodiments, the component 305 is disposed on the top surface 301a of the printed circuit board 300 opposite the bottom surface 101b of the connector 100 and is located within the annular region R enclosed by the solder joints 350. In some embodiments, component 305 is electrically connected to printed circuit board 300, for example, by a solder ball. It should be understood that the number and positions of the elements 305 in the drawings are merely illustrative, and the disclosure is not limited thereto. Depending on product requirements and design, various components may be placed at other suitable locations on the top surface 301a of the printed circuit board 300 (e.g., outside the annular region R), the bottom surface 301b, or any suitable location on both the top surface 301a and the bottom surface 301b. .

Referring to FIGS. 1, 2B, and 3B, the connector 100 is connected to the printed circuit board 300. For example, the positioning post 108b of the connector 100 is aligned with the positioning hole 308 of the printed circuit board 300, and then the positioning post 108b is passed through the positioning hole 308 to connect the connector 100 with the printed circuit board 300. The conductive terminals 103 of the connector 100 and the pads 302 of the printed circuit board 300 are disposed at positions corresponding to each other. After the connector 100 is connected to the printed circuit board 300, the conductive terminals 103 and the pads 302 are electrically and physically in contact with each other. In some embodiments, the positioning post 108b and the positioning hole 308 are engaged with each other to fix the connector 100 to the printed circuit board 300. In some embodiments, after the connector 100 is secured to the printed circuit board 300, the free portion 103b of the conductive terminal 103 is pressed into physical contact with the bottom surface of the second surface 101b of the substrate 101 and the perforations 104. In other embodiments, after the connector 100 is secured to the printed circuit board 300, the free portion 103b of the conductive terminal 103 is pressed into proximity to, but not in contact with, or partially in contact with the bottom surface of the second surface 101b and the through hole 104 of the substrate 101. . Although the entire free portion 103b of the conductive terminal 103 is shown to be fully contacted with the substrate 101 and the through hole 104, the present disclosure is not limited thereto. Depending on the product requirements and design, after the connector 100 is secured to the printed circuit board 300, the free portion 103b of the conductive terminal 103 can be in full, partial or non-contact with the substrate 101 and/or the perforations 104. Although two connectors 100 are shown in the figures, the disclosure is not limited thereto.

Referring to FIGS. 1, 2C, and 3C, the protective frame 150 is disposed on the top surface 301a of the printed circuit board 300. In some embodiments, the protective frame 150 is soldered to the top surface 301a of the printed circuit board 300, and the soldering surface 350 for the soldering is provided on the top surface 301a of the printed circuit board 300, but the disclosure is not limit. In an alternative embodiment, the protective frame 150 can also be mounted on the printed circuit board 300 using a detachable assembly. The detachable assembly method includes, for example, connection using a snap element, a positioning member, the like, screw fastening with a screw element or the like, or a combination thereof.

The protective frame 150 includes a metal, a metal alloy, or the like, such as copper or an alloy thereof. The protective frame 150 has a hollow annular frame structure. The contour of the protective frame 150 is set corresponding to the contour of the solder joint 350. In some embodiments, the protective frame 150 includes an annular frame 151, and the annular region R' enclosed by the inner sidewall S1 of the frame 151 corresponds to the annular region R' surrounded by the solder joints 350 of the printed circuit board 300. . In some embodiments, the protective frame 150 further includes a snap member (or locator) 152 located on the frame 151. The engaging member 152 is coupled to the frame 151 and protrudes from the top surface of the frame 151, and may also be referred to as a snap projection. The engaging member 152 is for engaging with the printed circuit board 200.

In some embodiments, the connector 100 is disposed outside of the annular region R' of the protective frame 150. In other words, the connector 100 is located outside the outer side wall S2 of the protective frame 150. The outer side wall S2 of the protective frame 150 may or may not be in contact with the connector 100. For example, a portion of the protective frame 150 can be laterally disposed between the two connectors 100 such that the connectors 100 are spaced apart from one another. In some embodiments, a portion of the outer sidewall S2 of the protective frame 150 can be in contact with a sidewall of the substrate 101 of the connector 100. The component 305 of the printed circuit board 300 is located within the annular region R' of the protective frame 150 and is laterally surrounded by the protective frame 150. The protective frame 150 can have any suitable shape and contour depending on product design and needs.

Referring to FIGS. 1 , 2D, 3B, and 3C, the printed circuit board 200 is disposed on and connected to the connector 100 and the protective frame 150. The shape of the printed circuit board 200 may be a regular shape such as a square, a rectangle, a polygon, or the like, or other irregular shape. Printed circuit board 200 can have any suitable shape depending on product design and needs. Printed circuit board 200 and printed circuit board 300 can have the same or different shapes and sizes. In some embodiments, the size (eg, width, length, area, etc.) of the printed circuit board 200 is less than the size of the printed circuit board 300.

Referring to FIGS. 1 , 3B and 3C , in some embodiments, the printed circuit board 200 includes pads 202 , positioning holes 208 , snap grooves 252 , and a plurality of components 205 and 210 . The pad 202 is disposed on the bottom surface 201b of the printed circuit board 200 opposite to the connector 100, and is disposed at a position corresponding to the conductive terminal 102 of the connector 100 for electrically connecting to the connector 100. The pad 202 includes a conductor material such as a metal or a metal alloy. For example, the pads 202 can comprise copper, aluminum, alloys thereof, or the like.

The positioning hole 208 passes through the printed circuit board 300 and is disposed at a position corresponding to the positioning post 108a of the connector 100. The engagement groove 252 (FIG. 1) is disposed at a position corresponding to the engaging member 152 of the protection frame 150. In some embodiments, the engaging groove 252 passes through the printed circuit board 200, but the disclosure is not limited thereto. In an alternate embodiment, the snap groove 252 is recessed from the bottom surface 201b of the printed circuit board 200 without passing through the printed circuit board 200.

Referring to Figures 1 and 3C, in some embodiments, printed circuit board 200 includes a plurality of components 205 and 210, such as integrated circuit wafers and the like. Elements 205 and 210 can include active elements, passive elements, or a combination thereof. The active element includes, for example, a transistor, a diode, or the like. Passive components include, for example, capacitors, resistors, inductors, and the like. The dimensions of the plurality of elements 205 and 210 may be the same or different from one another and may be the same type or different types of elements. In some embodiments, the component 205 is disposed on the bottom surface 201b of the printed circuit board 200 opposite the top surface 101a of the connector 100 and is located within the annular region R' of the protective frame 150, laterally surrounded by the protective frame 150. Element 210 is disposed on top surface 201a of printed circuit board 200. In some embodiments, elements 205 and 210 are electrically connected to printed circuit board 200, for example, by solder balls. It should be understood that the number and positions of the elements 205 and 210 in the drawings are merely illustrative, and the disclosure is not limited thereto. Depending on product requirements and design, various components may be placed at any suitable location on top surface 201a, bottom surface 201b, or both top surface 201a and bottom surface 201b of printed circuit board 200.

1, 2D, 3B, and 3C, the positioning post 108a of the connector 100 passes through the positioning hole 208 of the printed circuit board 200, and the engaging member 152 of the protection frame 150 and the engaging groove 252 of the printed circuit board 200. The printed circuit board 200, the connector 100, the protective frame 150, and the printed circuit board 300 are connected and fixed together. In some embodiments, after the printed circuit board 200 is coupled to the connector 100, the free portion 102b of the conductive terminal 102 of the connector 100 is pressed into physical contact with the top surface 101a of the substrate 101 and the top surface of the via 104. In other embodiments, after the printed circuit board 200 is connected to the connector 100, the free portion 102b of the conductive terminal 102 of the connector 100 is pressed to be close to but not in contact with the top surface 101a of the substrate 101 and the top surface of the through hole 104. Or partial contact. Although the entire free portion 102b of the conductive terminal 102 is shown to be fully contacted with the substrate 101 and the through hole 104, the present disclosure is not limited thereto. Depending on product requirements and design, after the printed circuit board 200 is coupled to the connector 100, the free portion 102b of the conductive terminal 102 can be in full, partial or non-contact with the substrate 101 and/or the via 104.

Referring to FIG. 3C, the inner side wall S1 of the protective frame 150, the partial bottom surface 201b of the printed circuit board 200, and the top surface 301a of the printed circuit board 300 enclose a closed area ER. The component 205 and the component 305 are disposed in the enclosed area ER, and are laterally surrounded and protected by the protective frame 150. In some embodiments, element 205 and element 305 are elements that require electromagnetic interference protection, and protection frame 150 can be used to shield electromagnetic interference generated by element 205 and element 305 located within the enclosed area ER. Although both the printed circuit board 200 and the printed circuit board 300 are shown in FIG. 3C as including components located in the enclosed area ER, the disclosure is not limited thereto. Depending on the design and needs of the product, the enclosed area ER may also include only components disposed on the bottom surface of the printed circuit board 200 or only components disposed on the top surface of the printed circuit board 300.

Referring to FIGS. 1 and 2D , in some embodiments, the printed circuit board stack structure 500 can further include a build-up board 400 disposed over the printed circuit board 200 . The fixing plate 400 is soldered to the printed circuit board 200, for example, and the printed circuit board 200 includes the solder joints 240 for the soldering, but the disclosure is not limited thereto. In an alternate embodiment, the gusset plate is attached to the printed circuit board 200. The gusset plate comprises a rigid material such as a metal. The build-up plate 400 can be used to prevent warpage of the printed circuit board 200. In the disclosed embodiment, the mounting plate 400 is optionally disposed on the printed circuit board 200. For the sake of brevity, the build-up plate 400 is not shown in Figures 3B and 3C.

In the above embodiment, the printed circuit board 200 and the printed circuit board 300 and the connector 100 are connected and fixed to each other by a positioning member (separable fastener) 510. The positioning member 510 includes positioning posts 108a and 108b on the connector 100, and positioning holes 208 and 308 on the printed circuit boards 200 and 300, respectively. However, the disclosure is not limited thereto. Other types of separable fasteners can also be used in alternative embodiments. For example, the printed circuit board 200, the printed circuit board 300, and the connector 100 can be locked together by screwing by means of screwing elements. Alternatively, the printed circuit board 200 and the printed circuit board 300 and the connector 100 are first positioned by the positioning member 510, and the three are locked together by the screwing elements.

In the above embodiment, the protective frame 150 is soldered to the printed circuit board 300 and is engaged with the printed circuit board 200, but the disclosure is not limited thereto. The protective frame 150 and the printed circuit boards 200 and 300 can be connected by suitable means such as welding, snapping, screw locking, and the like.

In summary, the present invention electrically connects different printed circuit boards to each other by a connector having conductive springs, and uses a detachable fastener to secure the printed circuit board and the connector together. In this way, compared with the traditional way of using BGA/BGA interposer to solder the printed circuit board, the new creation omits two SMT processes, avoiding or reducing the soldered parts on the printed circuit board caused by the high temperature tin furnace. Damage or warpage of the printed circuit board. In addition, since the printed circuit board and the connector created by the present invention are detachably assembled by separable fasteners, the printed circuit board can be easily replaced if some components in the printed circuit board stack fail. The stack structure is disassembled for repair and the printed circuit board stack can be reattached together by separable fasteners after repair is complete.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the novel creation, and any person skilled in the art can make some changes without departing from the spirit and scope of the novel creation. Retouching, the scope of protection of this new creation is subject to the definition of the scope of the patent application attached.

100‧‧‧Connector  101‧‧‧Substrate  101a‧‧‧ first surface  101b‧‧‧ second surface  102, 103‧‧‧ conductive terminals  102a, 103a‧‧‧Fixed Department  102b, 103b‧‧ Free Department  104‧‧‧Perforation  107‧‧‧Connecting parts  108a, 108b‧‧‧ positioning column  150‧‧‧protection frame  151‧‧‧ frame  152‧‧‧Clamps  200, 300‧‧‧ Printed circuit boards  201a, 301a‧‧‧ top  201b, 301b‧‧‧ bottom  202, 302‧‧‧ pads  205, 210, 305‧‧‧ components  208, 308‧‧‧ positioning holes  252‧‧‧ snap groove  350‧‧‧ solder joints  400‧‧‧Fixed plate  500‧‧‧Printed circuit board stack structure  510‧‧‧ Positioning parts  ER‧‧‧closed area  R, R’‧‧‧ ring zone  A-A’, B-B’, I-I’‧‧‧ lines  S1‧‧‧ inner side wall  S2‧‧‧ outer side wall  

1 is a perspective exploded view of a printed circuit board stack structure in accordance with some embodiments of the present invention.  2A-2D are assembled schematic views of a printed circuit board stack structure in accordance with some embodiments of the present invention.  3A is a cross-sectional view of a connector in accordance with the present invention, and FIG. 3A is, for example, a cross-sectional view taken along line I-I' of connector 100 of FIG.  3B and FIG. 3C are cross-sectional views showing a printed circuit board stack structure according to some embodiments of the present invention, wherein FIG. 3B is a cross-sectional view taken along line AA' of FIG. 2D, and FIG. 3C is a line B-B along FIG. 2D. 'Cross section view'.  4 is a partial schematic view of a connector in accordance with some embodiments of the present invention.  

Claims (11)

A printed circuit board stack structure comprising:  a first printed circuit board comprising a first pad;  a second printed circuit board comprising a second pad;  a connector disposed between the first printed circuit board and the second printed circuit board and connected to the first printed circuit board and the second printed circuit board by a detachable fastener Connectors include:  a substrate having first and second surfaces opposite to each other;  a first conductive elastic piece on the first surface and in contact with the first pad;  a second conductive elastic piece on the second surface and in contact with the second pad;  A protective frame is disposed side by side with the connector between the first printed circuit board and the second printed circuit board.   The printed circuit board stack structure of claim 1, wherein the first conductive elastic piece includes a first fixing portion and a first free portion connected to each other, and the second conductive elastic piece includes a second fixing connected to each other Ministry and the second free department. The printed circuit board stack structure of claim 1, wherein the connector further comprises a through hole in the substrate and passing through the substrate to electrically connect the first conductive elastic piece with the The second conductive elastic piece. The printed circuit board stack structure of claim 1, wherein the separable fastener comprises:  a first positioning post and a second positioning post respectively located on the first surface and the second surface of the substrate of the connector;  a first positioning hole located in the first printed circuit board;  a second positioning hole located in the second printed circuit board,  The first positioning post and the second positioning post respectively pass through the first positioning hole and the second positioning hole to connect the first printed circuit board, the connector, and the second The printed circuit boards are connected and fixed together.   The printed circuit board stack structure of claim 1, wherein the first printed circuit board further comprises a first component that is laterally surrounded by the protective frame. The printed circuit board stack structure of claim 5, wherein the second printed circuit board further comprises a second component laterally surrounded by the protective frame. The printed circuit board stack structure of claim 1, wherein the protection frame comprises an annular frame body and a snap member protruding from a top surface of the frame body, and the bottom surface of the protection frame is soldered to In the second printed circuit board, the engaging member is engaged with the engaging groove of the first printed circuit board. The printed circuit board stack structure of claim 1, wherein the connector is disposed outside an outer sidewall of the protective frame. The printed circuit board stack structure of claim 8, wherein the outer sidewall of the protective frame is spaced apart from a sidewall of the substrate of the connector. The printed circuit board stack structure of claim 1, wherein the connector comprises a plurality of connectors, and the protective frame is located between the plurality of connectors. The printed circuit board stack structure of claim 1, further comprising a fixing plate disposed on the first printed circuit board.