Disclosure of Invention
The application aims to provide a micro-electromechanical sensor packaging structure and a manufacturing method thereof, which are used for solving the problems of high production cost, complex process flow, low product yield, poor consistency and low production efficiency in the prior art. The production efficiency and the product yield of the micro-electromechanical sensor packaging structure are improved, the process flow is simplified, and the production cost is reduced.
In one aspect, the present application provides a mems package structure, including:
a first substrate;
a second substrate disposed on one side of the first substrate;
the shell is arranged on the other side of the first substrate, and a cavity is formed between the shell and the first substrate;
the chip is arranged on the inner side of the shell, is positioned in the cavity and is electrically connected with the first substrate through a metal wire;
the first substrate is provided with a first through hole, the area of the first through hole is larger than that of the chip, and the position of the first through hole corresponds to the position of the chip.
Preferably, the chip includes a MEMS chip and an ASIC chip, and the MEMS chip, the ASIC chip, and the first substrate are electrically connected through the metal line.
Preferably, the housing is provided with a second through hole, which is located inside the MEMS chip.
Preferably, a first metal layer is disposed on a side surface of the first through hole in the first substrate and at least a partial area on one side of the first substrate, and a second metal layer is disposed on the other side of the first substrate.
Preferably, at least part of the area of the side of the second substrate adjacent to the first substrate is provided with a third metal layer.
Preferably, a first solder mask layer is arranged on a part of the area of the first metal layer, a second solder mask layer is arranged on a part of the area of the third metal layer, and the position of at least part of the second solder mask layer corresponds to the position of the first solder mask layer.
Preferably, the sum of the thicknesses of the first solder mask layer, the second solder mask layer and the third metal layer is not smaller than the wire arc height of the metal wire.
On the other hand, the application also provides a manufacturing method of the micro-electromechanical sensor packaging structure, which is characterized by comprising the following steps:
connecting the plurality of shells with the first substrate;
chips are respectively attached to the plurality of shells;
electrically connecting the chip with the first substrate;
connecting the second substrate with the first substrate to form a semi-finished product;
cutting and separating the semi-finished product to obtain a plurality of independent micro-electromechanical sensor packaging structures;
the first substrate and the second substrate are respectively provided with a plurality of micro-electromechanical sensor units, a plurality of cavities are formed between the first substrate and the shell, the chip is positioned in the cavities, the first substrate corresponds to the second substrate, and the first substrate and the second substrate respectively comprise a plurality of micro-electromechanical sensor units.
Preferably, the chip comprises a MEMS chip and an ASIC chip, which are disposed on the housing by a surface mount technology, and the MEMS chip, the ASIC chip and the first substrate are connected by a metal wire.
Preferably, a first metal layer is arranged in a partial area of one side of the first substrate adjacent to the second substrate, and a first solder mask layer is arranged in a partial area of the first metal layer; a third metal layer is arranged on one side of the second substrate adjacent to the first substrate, and a second solder mask layer is arranged on a partial area of the third metal layer; and the sum of the thicknesses of the first solder mask layer, the second solder mask layer and the third metal layer is not smaller than the wire arc height of the metal wire.
Preferably, the shell and the first substrate and the second substrate are connected through a connecting material, and the connecting material comprises at least one of solder paste, conductive adhesive and insulating adhesive.
Preferably, the electrical connection is provided while the mechanical connection is made, depending on whether an electrically conductive connection material is used as required.
Preferably, the first substrate and the second substrate are connected by single press-fit alignment, so as to reduce errors.
According to the micro-electromechanical sensor packaging structure and the manufacturing method provided by the embodiment of the application, through adopting the packaging structure design, under the condition of using a conventional process method and materials, the micro-electromechanical sensor packaging structure which is originally required to be produced one by one is subjected to mass production, so that the consistency of produced products is controlled, the production efficiency and the product yield are improved, and furthermore, the first substrate and the second substrate are connected in a single-press-fit alignment mode, so that the error is reduced, the process flow is simplified, and the production cost is reduced.
Furthermore, in the design of the packaging structure, no special requirement for matching longitudinal dimensions exists among all the components, materials of the parts to be cut and separated are similar, a certain height difference exists between the parts to be cut and separated and the bottom surface of the shell, and the parts to be cut and separated can be cut in a targeted manner by setting the feeding amount of the cutter. Meanwhile, positioning marks can be arranged on the edges of the first substrate and the second substrate, and alignment precision between the substrates can be remarkably improved. The thickness and uniformity of the connecting material can be effectively controlled by coating the connecting material (solder paste) through the screen plate, and the connecting quality of the product is ensured.
Detailed Description
The application will be described in more detail below with reference to the accompanying drawings. Like elements are denoted by like reference numerals throughout the various figures. For clarity, the various features of the drawings are not drawn to scale. Furthermore, some well-known portions may not be shown. The semiconductor structure obtained after several steps may be depicted in one figure for simplicity.
It will be understood that when an architecture is described as being "on" or "over" another layer, another region, it can be referred to as being directly on the other layer, another region, or further layers or regions can be included between the architecture and the other layer, another region. And if the device is flipped, the one layer, one region, will be "under" or "beneath" the other layer, another region.
If, for the purposes of describing a situation directly overlying another layer, another region, the expression "directly overlying … …" or "overlying … … and adjoining" will be used herein.
Numerous specific details of some embodiments of the application, such as device structures, materials, dimensions, processing and techniques, are set forth below in order to provide a more thorough understanding of the application. However, as will be understood by those skilled in the art, the present application may be practiced without these specific details.
The application may be embodied in various forms, some examples of which are described below.
Fig. 1 shows a schematic diagram of a mems package structure according to an embodiment of the present application, and the mems package structure 100 includes: the first substrate 110, the second substrate 120, the housing 130, and the chip 140. The upper surface of the first substrate 110 is adjacent to the lower surface of the second substrate 120, the lower surface of the first substrate 110 is adjacent to the housing 130, a cavity is formed between the housing 130 and the first substrate 110, and the chip 140 is disposed inside the housing 130 and is located in the cavity.
Of course, the first substrate 110 is provided with a first through hole 111, the first through hole 111 is located above the chip 140, and the area of the first through hole 111 is larger than the area of the chip 140, so as to facilitate the mounting of the chip 140. The first metal layer 112 is disposed on a partial area of the upper surface of the first substrate, and further, the first metal layer 112 may be further disposed on a sidewall of the first through hole 111 in an extending manner, and a first solder mask 1121 is further disposed on a portion of the first metal layer 112. The first substrate 110 is further provided on a lower surface thereof with a second metal layer 113 for connection with the case 130 through a connection material 150.
The lower surface of the second substrate 120 is provided with a third metal layer 121, a second solder mask 1211 is further provided on a portion of the third metal layer 121, a portion of the second solder mask 1211 corresponds to the first solder mask 1121, and the second substrate 120 is connected to the first metal layer on the first substrate 110 through the connection material 150 on a portion of the third metal layer 121 not covered by the second solder mask 1211.
The housing 130 is, for example, in a bottle cap shape, and includes a second through hole 131, wherein an upper surface of an edge of the housing 130 is connected to a second metal layer on a lower surface of the first substrate 110 through a connecting material 150, so that a cavity is formed between the housing 130 and the first substrate 110, and the chip 140 is disposed inside the housing 130 and is located in the cavity. The chip 140 includes, for example, a MEMS chip 141 and an ASIC chip 142, wherein the MEMS chip 141, the ASIC chip 142, and the first metal layer 112 of the first substrate 110 are electrically connected in sequence by a metal line 143, and the second through hole 131 is located inside the MEMS chip 141.
The connection material 150 includes solder, solder paste, conductive paste, insulating paste, etc., and corresponding mechanical connection is provided between the components to be connected through the connection material 150, and whether or not to use the conductive connection material 150 can be determined as required, and corresponding electrical connection is provided while mechanical connection is provided.
Further, since the chip 140 is electrically connected to the first metal layer 112 on the first substrate 110 through the metal lines 143, the sum of the thicknesses of the first solder mask 1121, the second solder mask 1211 and the third metal layer 121 should be not less than the wire arc height of the metal lines 143 to reserve enough space for the arrangement of the metal lines 143.
The housing 130 is connected to the second metal layer 113 on the lower surface of the first substrate 110, for example, by soldering, and the second substrate 120 is connected to the first substrate 110 by applying solder paste on the third metal layer, performing lamination alignment with the upper surface of the first substrate 110, and performing reflow soldering to cure the solder paste, thereby completing the connection between the first substrate 120 and the first substrate 110.
Fig. 2 is a schematic diagram of a manufacturing method of a mems package structure according to an embodiment of the present application, where specific steps include:
s10, connecting a plurality of shells with a first substrate; the first substrate 110 is a jigsaw design, and includes a plurality of mems units, a second metal layer 113 connected to the housing 130 is disposed at a corresponding position of each mems unit, each housing 130 is connected to one mems unit on the first substrate 110, and a connecting material 150, such as solder, connects the plurality of housings 130 to the corresponding mems units in the first substrate 110 by soldering.
S20, respectively attaching chips to the plurality of shells; the chip 140 includes, for example, a MEMS chip 141 and an ASIC chip 142, and the first substrate 110 is provided with a first through hole 111, where the first through hole 111 corresponds to the position of the chip 140, for example, is located above the chip 140, and the area of the first through hole 111 is larger than the area of the chip 140, so as to facilitate mounting of the chip 140. Taking one micro-electro-mechanical sensor unit as an example, a chip 140 is disposed on the inner side of the case 130 through the first through hole 111, and the MEMS chip 141 and the ASIC chip 142 are mounted on the inner side of the case 130 by SMT (surface mounting technology: surface mount technology), for example. Of course, the housing 130 is provided with a second through hole 131, and the second through hole 131 is located inside the MEMS chip 141.
S30, forming a metal wire between the chip and the surface of the first substrate; specifically, metal wires may be disposed between the MEMS chip 141 and the ASIC chip 142, and between the ASIC chip 142 and the first metal layer 112 on the surface of the first substrate 110, and the chip 140 is electrically connected to the first metal layer 112 on the surface of the first substrate 110 through the metal wire 143 to form corresponding conductive channels.
S40, connecting the second substrate with the first substrate to prepare a semi-finished product; the second substrate 120 is, for example, a tile design similar to that of the first substrate 110, and the second substrate 120 corresponds to the first substrate 110 and has a plurality of micro-electromechanical sensor units. Of course, components such as a capacitor and resistor may be provided on the second substrate in advance, and then connected to the first substrate 110. The second substrate 120 and the first substrate 110 are connected by reflow soldering after the second substrate 120 and the first substrate 110 are aligned and pressed together, for example, by solder paste.
S50, cutting and separating the semi-finished product to obtain a plurality of independent micro-electromechanical sensor packaging structures. Since the first substrate 110 and the second substrate 120 are both designed in a jigsaw manner, the semi-finished product obtained after the connection between the second substrate and the first substrate in the previous step needs to be cut and separated to obtain an independent mems packaging structure. Since the materials of the first substrate 110 and the second substrate 120 are substantially the same, the semi-finished product can be cut by one feeding with the corresponding cutter.
The manufacturing of the mems package structure is not necessarily performed according to the sequence of steps S10 to S50, for example, the sequence of steps S10 and S20 may be interchanged, and the manufacturing of the mems package structure is not affected.
The manufacturing method enables the micro-electromechanical sensor packaging structure which is originally required to be produced one by one to realize the mass production of the whole board, is beneficial to controlling the consistency of produced products, improves the yield of the products, and has strong production stability and practicability because the related size matching is also a problem which can be solved by the conventional reflow soldering process.
Fig. 3 shows a partial schematic view of the first substrate and the housing according to an embodiment of the application. The first substrate 110 is formed by processing raw materials, for example, a PCB board, and the edge area of the first substrate 110 is similar to the process edge, and corresponding positioning marks can be set to ensure the alignment accuracy between the first substrate and the rest components.
The figure shows a partial cross-section of a first substrate 110, which comprises 3 micro-electro-mechanical sensor units in the lateral direction, and takes one micro-electro-mechanical sensor unit as an example, a first through hole 111 is provided on the first substrate 110, a first metal layer 112 is provided on a partial area on one side of the first substrate, and a first solder mask layer 1121 is further provided on the first metal layer 112, and a second metal layer 113 is provided on a partial area on the other side of the first substrate 110, as a bonding pad connected to the housing 130. The first substrate 110 is faced down with the first metal layer 112, the inner surface of the housing 130 faces the second metal layer 113 of the first substrate 110, and the edge of the housing 130 is aligned with the second metal layer 113, the housing 130 is connected to the first substrate 110 by the connecting material 150, such as solder, and the edge of the housing 130 is welded to the second metal layer 113, so that a cavity is formed between the housing 130 and the first substrate 110. The housing 130 is provided with a second through hole 131, the second through hole 131 is located above the first through hole 111, and the area of the second through hole 131 is smaller than that of the first through hole 111.
Fig. 4a shows a partial schematic view of a mounted chip according to an embodiment of the application. The connected housing 130 and the first substrate 110 are turned over, so that the outside of the housing 130 faces downward, the first metal layer 112 of the first substrate 110 faces upward, and the chip 140 is mounted on the inside of the housing 130. Also, taking one MEMS unit as an example, the housing 130 is already connected to the first substrate 110, and a corresponding cavity is formed between the two, and the chip 140 is mounted through the first through hole 111 on the first substrate 110 at a position on the inner side of the housing 130 opposite to the first through hole 111, where, of course, the (projected) area of the chip 140 is smaller than the (projected) area of the first through hole 111, and the chip 140 includes, for example, the MEMS chip 141 and the ASIC chip 142, and is mounted by SMT, and cured by reflow soldering. The SMT mounting mode is more efficient than other mounting modes such as Diebond and the like, and is also more beneficial to controlling the consistency of production. The case 130 includes a second through hole 131, and the second through hole 131 is located inside the MEMS chip 141 when the MEMS chip 141 is mounted.
After the chip 140 is mounted, a metal line 143 is provided to electrically connect the MEMS chip 141, the ASIC chip 142, and the first electrode layer 112 on the surface of the first substrate 110 in this order. The first metal layer 112 may include a plurality of bonding pads connected or independent, and since the second substrate 120 is disposed above the first substrate 110 in the subsequent steps, the metal line 143 between the ASIC chip 142 and the first electrode layer 112 on the surface of the first substrate 110 is at risk of being crushed (by the second substrate 120), so that it contacts the first metal layer 112 on the sidewall of the first through hole 111, resulting in a short circuit. Preferably, as shown in fig. 4b, the longitudinal dimension of the first metal layer 112 disposed on the sidewall of the first through hole 111 is reduced to have a certain distance from the surface of the first substrate 110, so as to avoid the risk of short-circuiting and the occurrence of crush damage to the metal line 143.
Fig. 5 is a schematic partial view of a second substrate connected to a first substrate according to an embodiment of the present application, and the above-described parts are not repeated here. The third metal layer 121 is disposed in a partial area of one side surface of the second substrate, the second solder mask 1211 is disposed on a part of the third metal layer 121, and solder paste is selected as the connecting material 150 between the second substrate and the first substrate, and the solder paste is coated at the position, which is not covered by the second solder mask 1211, in a part of the third metal layer 121. Similarly, the edge region of the second substrate 120 is also provided with a structure similar to the process edge, which corresponds to the edge region of the first substrate 110.
The third metal layer 121 is disposed on the second substrate 120, and is aligned with and pressed against the first substrate 110 with the first metal layer 112, and the solder paste is cured by reflow soldering, so that the second substrate 120 is connected with the first substrate 110. The first substrate 110 and the second substrate 120 are connected by single lamination alignment and reflow soldering, so as to reduce the accumulated error caused by multiple lamination alignments, and improve the product yield.
Of course, before the second substrate 120 is connected to the first substrate 110, the required electrical components or chips such as capacitors, resistors, diodes, etc. may be provided on the second substrate 120 in advance, and the electrical components or chips may be subjected to operations such as encapsulation, etc. after the devices on the second substrate 120 are provided, the devices may be combined and connected to the first substrate 110.
Further, the spatial dimensions of the region where the chip 140 is located are ensured by the first and second solder resists 1121 and 1211 and the third metal layer 121. Specifically, the sum of the thicknesses of the first solder resist layer 1121, the second solder resist layer 1211, and the third metal layer 121 is not less than the wire arc height of the metal wire 143.
Fig. 6 shows a partial schematic view of a cut separation performed by an embodiment of the present application. When the semi-finished product is cut and separated, the outer surface of the shell 130 is downward and is directly attached to the lower film 210, and impurities are prevented from entering the second through holes 131 by the film 210. The plurality of micro-electromechanical sensor units in the semi-finished product are cut and separated by the cutter 220 to obtain the independent micro-electromechanical sensor packaging structure 100.
The first substrate 110 and the second substrate 120 are generally made of PCB materials, the cutter 220 may be a steel cutter or other hard cutters, and specifically, since a certain distance is provided between the first substrate 110 and the second substrate 120 and the film 210, the feeding depth of the cutter 220 can be set, and under the condition of not damaging the film 210, the cutting of the first substrate 110 and the second substrate 120 is completed, so that the plurality of mems packaging structures in the semi-finished product are separated from each other.
In the above description, technical details of patterning, dicing, and the like of each device are not described in detail. Those skilled in the art will appreciate that layers, regions, etc. of the desired shape may be formed by a variety of techniques. In addition, to form the same structure, those skilled in the art can also devise methods that are not exactly the same as those described above. In addition, although the embodiments are described above separately, this does not mean that the measures in the embodiments cannot be used advantageously in combination.
The embodiments of the present application are described above. However, these examples are for illustrative purposes only and are not intended to limit the scope of the present application. The scope of the application is defined by the appended claims and equivalents thereof. Various alternatives and modifications can be made by those skilled in the art without departing from the scope of the application, and such alternatives and modifications are intended to fall within the scope of the application.