CN211387270U - Press fit jig - Google Patents

Abstract

The utility model relates to a micro-electromechanical system encapsulates the field, especially relates to a pressing fixture, including the buckle of the fixed plate that two symmetries set up, fixed plate and the spring of evenly fixing on the fixed plate, the symmetry is equipped with a plurality of fixed spring's standing groove on the fixed plate, the standing groove is 5X 11 array distribution on two fixed plate correspond the terminal surface, still evenly be equipped with the bleeder vent that runs through the fixed plate on the fixed plate, the bleeder vent is 4X 8 array distribution on two fixed plates, two still the symmetry is equipped with the fixed orifices of fixed column on the fixed plate. The force of the press fit is controlled through the spring, so that the stress of the welding surface is more uniform, the flatness and the welding quality of the welding surface can be improved, and the welding effect of the upper PCB, the lower PCB and the middle PCB is basically consistent.

Description

Press fit jig

[ technical field ] A method for producing a semiconductor device

The invention relates to the field of micro-electro-mechanical system packaging, in particular to a pressing fixture.

[ background of the invention ]

MEMS is a Micro-electro-mechanical System, which is called Micro-electro-mechanical System in English, and refers to a sensor device with a size of several millimeters or even smaller, and the internal structure of the sensor device is generally in the micrometer or even nanometer level, and the sensor device is an independent intelligent System. Briefly, the MEMS is a silicon-based sensor formed by miniaturizing mechanical components of a conventional sensor, fixing a device on a silicon wafer (wafer) by a three-dimensional stacking technique, for example, a three-dimensional through-silicon via (TSV) technique, and finally cutting and assembling the device in a specially-customized packaging form according to different application occasions. The MEMS has the advantages of miniaturization and high integration degree which cannot be achieved by the common sensor simultaneously due to the cost advantage brought by the IC silicon chip processing batch production which cannot be achieved by the common sensor.

The MEMS microphone can be divided into a top sound inlet mode and a bottom sound inlet mode according to the sound inlet mode, wherein the bottom sound inlet mode has a larger acoustic back cavity, so the signal-to-noise ratio and the frequency response characteristic are better, in order to improve the MEMS microphone with the top sound inlet mode, an improvement process through PCB plate pressing is provided, the top sound inlet mode is changed into a mode of soldering three layers of PCBs together after being pressed, soldering tin layers are arranged on the upper end surface and the lower end surface of the middle layer PCB plate, so that a product has an effect almost equal to the bottom sound inlet mode on the premise of the top sound inlet mode, but the packaging mode has a plurality of problems in the PCB plate pressing process, the problems need to be optimized, the reliability of the product is improved, the bad phenomenon is avoided, the alignment pressing precision and the stress requirements of the MEMS microphone on the PCBs are high, and the welding reliability and the welding quality are influenced by the heat absorption of a jig in the reflow process, the problems of cracking and air leakage of a welding layer, overflow and short circuit of solder paste and the like often occur in the actual production process, and serious hidden danger of product quality exists in the pressing process, so that how to improve the reliability and quality of the reflow soldering pressing process becomes a difficult problem to be solved urgently in manufacturing of the MEMS microphone.

The invention is provided for overcoming the defects of the prior art.

[ summary of the invention ]

The invention aims to overcome the defects of the prior art and provides a pressing jig which presses three layers of PCBs through uniformly distributed springs on a fixing plate and uniformly heats the PCBs through hot air entering between the three layers of PCBs.

The invention can be realized by the following technical scheme:

the utility model provides a press fit jig, includes the fixed plate that two symmetries set up, fixed plate's buckle and evenly fix the spring on the fixed plate, the symmetry is equipped with a plurality of fixed spring's standing groove on the fixed plate, the standing groove is 5X 11 array distribution on two fixed plate correspond the terminal surface, still evenly be equipped with the bleeder vent that runs through the fixed plate on the fixed plate, the bleeder vent is 4X 8 array distribution on two fixed plates, two still the symmetry is equipped with the fixed orifices of fixed column on the fixed plate. The PCB comprises an upper PCB, a lower PCB and a middle PCB, wherein solder paste is printed on the lower end surface of the upper PCB and the upper end surface of the lower PCB through silk screens, the three layers of PCBs are placed between two fixed plates after being fixed, the fixed columns are fixed on the fixed holes of the two PCBs after penetrating through the positioning holes on the PCBs through the fixed columns, the two end surfaces of the PCBs are mutually extruded through springs on the two fixed plates, the side edges of the two fixed plates are fixed through buckles, after the fixed plates and the PCBs are fixed through the buckles, a pressing jig is placed into a hot air soldering machine, the hot air soldering machine blows hot air to the two fixed plates, the hot air uniformly enters the PCBs after passing through the air holes on the fixed plates, the solder paste on the welding layer on the PCBs is heated, the upper PCB, the lower PCB and the middle PCB are fixed, the upper PCB, the lower PCB and the middle PCB pass through the fixed columns, and the alignment accuracy of welding can be ensured, also be favorable to welded stability, and evenly extrude upper PCB board and lower floor PCB board through the spring of evenly fixing on two fixed plates, it is even to have guaranteed that each position atress on upper PCB board and the lower floor PCB board is even, the quality after the soldering tin has been guaranteed, can effectively avoid the problem of tin layer fracture after the soldering tin, and hot-blast bleeder vent that evenly distributes on two upper and lower fixed plates enters into the pressfitting tool inside and heats the PCB board, can effectively guarantee to heat evenly, the quality of soldering tin has further been guaranteed, avoid the problem that the tin cream can not completely melt to produce, and through the fixed PCB board of spring array, the spring realizes cavity with PCB board fixed position, allow hot-blast passing through, thereby further guaranteed that the PCB board is heated evenly and guaranteed the quality of soldering tin.

Preferably, the fixing plate is made of a metal material. The metal material has better heat-conducting property.

Compared with the prior art, the invention has the following advantages:

1. the force of the press fit is controlled through the spring, so that the stress of the welding surface is more uniform, the flatness and the welding quality of the welding surface can be improved, and the welding effect of the upper PCB, the lower PCB and the middle PCB is basically consistent.

2. The spring is fixed regional and other face regions adopt the fretwork design, realize maximize heated air circulation efficiency, can guarantee that the face remains constant temperature throughout, is favorable to promoting the welding quality of face of weld, avoids appearing bad phenomena such as local welding harmfully or cold welding.

3. The hot-blast bleeder vent that enters into the pressfitting tool through evenly distributed on two upper and lower fixed plates is inside to the PCB board heating, can effectively guarantee to heat evenly, has further guaranteed the quality of soldering tin, avoids the problem production that the tin cream can not the complete melting.

[ description of the drawings ]

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

FIG. 1 is a schematic view of a fixing plate according to the present invention;

FIG. 2 is a schematic view of an assembly structure of the fixing plate and the spring according to the present invention;

FIG. 3 is a schematic diagram of a PCB structure of the present invention;

FIG. 4 is a schematic structural view of the present invention;

FIG. 5 is a schematic view of the upper fixing plate and the spring of the present invention;

FIG. 6 is a schematic view of the structure of the lower fixing plate, the spring and the fixing post of the present invention;

FIG. 7 is a view showing the effect of flowing hot air in reflow soldering according to the present invention;

in the figure: 1. a fixing plate; 2. a placement groove; 3. air holes are formed; 4. a fixing hole; 5. a spring; 6. fixing a column; 7. buckling; 8. a PCB board; 801. an upper PCB board; 802. a middle layer PCB board; 803. a lower PCB board; 804. welding the layers;

[ detailed description ] embodiments

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

as shown in fig. 1 to 7, a pressing fixture, including two fixed plate 1 that the symmetry set up, buckle 7 of fixed plate 1 and the spring 5 of evenly fixing on fixed plate 1, the symmetry is equipped with standing groove 2 of a plurality of fixed spring 5 on fixed plate 1, standing groove 2 is 5 × 11 array distribution on two fixed plate 1 correspond the terminal surface, still evenly be equipped with bleeder vent 3 that runs through fixed plate 1 on fixed plate 1, bleeder vent 3 is 4 × 8 array distribution on two fixed plates 1, still the symmetry is equipped with fixed orifices 4 of fixed column 6 on two fixed plates 1. The PCB 8 is composed of an upper PCB 801, a lower PCB 803 and a middle PCB 802, wherein solder paste is printed on the lower end surface of the upper PCB 801 and the upper end surface of the lower PCB 803 by silk screen printing, the three layers of PCBs 8 are placed between the two fixing plates 1 after being fixed, the fixing columns 6 are fixed on the fixing holes 4 of the two PCBs 8 after the fixing columns 6 pass through the positioning holes on the PCBs 8, the two end surfaces of the PCBs 8 are mutually extruded by the springs 5 on the two fixing plates 1, the side edges of the two fixing plates 1 are fixed by the buckles 7, after the fixing plates 1 and the PCBs 8 are fixed by the buckles 7, the pressing jig is put into a hot air soldering machine, the hot air soldering machine blows hot air to the two fixing plates 1, the hot air uniformly enters the PCBs 8 after passing through the air holes 3 on the fixing plates 1, the solder paste of the welding layer 804 on the PCBs 8 is heated, the upper PCB 801, the lower PCB 803 and the middle PCB 802 are fixed, the fixing column 6 penetrates through the upper layer PCB 801, the lower layer PCB 803 and the middle layer PCB 802, so that the alignment accuracy of welding can be ensured, the welding stability is also facilitated, and the springs 5 uniformly fixed on the two fixing plates 1 uniformly extrude the upper PCB 801 and the lower PCB 803, thereby ensuring that all positions on the upper PCB 801 and the lower PCB 803 are uniformly stressed, ensuring the quality after soldering, effectively avoiding the problem of tin layer cracking after soldering, and hot air enters the pressing jig through the air holes 3 uniformly distributed on the upper fixing plate 1 and the lower fixing plate 1 to heat the PCB 8, can effectively ensure even heating, further ensure the quality of soldering tin, avoid the problem that the solder paste can not be completely melted, and fix PCB board 8 through spring 5 array, spring 5 and PCB board 8 fixed position realize the cavity, allow hot-blast passing through, thereby further guaranteed that PCB board 8 is heated evenly and guaranteed the quality of soldering tin.

Wherein, the fixed plate 1 is made of magnesium-aluminum alloy. The metal material has better heat-conducting property.

The above description is only a preferred embodiment of the present invention, and it should be noted that a person skilled in the art can make various changes, modifications, substitutions and alterations to the embodiments without departing from the technical principles of the present invention, and such changes, modifications, substitutions and alterations should also be regarded as the protection scope of the present invention.

Claims (2)

1. A pressing jig is characterized in that: the fixing device comprises two symmetrically arranged fixing plates, buckles for fixing the fixing plates and springs uniformly fixed on the fixing plates, wherein the fixing plates are symmetrically provided with placing grooves for the plurality of fixing springs, the placing grooves are distributed on the corresponding end surfaces of the two fixing plates in a 5 x 11 array mode, air holes penetrating through the fixing plates are further uniformly formed in the fixing plates, the air holes are distributed on the two fixing plates in a 4 x 8 array mode, and the fixing holes for fixing the fixing columns are further symmetrically formed in the fixing plates.

2. The pressing jig according to claim 1, wherein: the fixing plate is made of metal materials.

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