A semiconductor packaging structure, device and packaging process thereof

Abstract

The invention discloses a semiconductor packaging structure, a device and a packaging process thereof, comprising the following steps: a resonator packaging step: providing a substrate, on which a plurality of ceramic resonators are evenly inverted, the bottom surface of the resonator is exposed, a conductive block is mounted at the position of the exposed bottom surface electrode pad, the resonator is plastic-sealed, and the packaging surface is horizontally ground until the top surface of the conductive block is exposed; a thermistor packaging step: mounting a thermistor at the corresponding position of each resonator on the ground packaging surface, the thermistor is electrically connected to the conductive block through an electroplated circuit, thereby achieving electrical connection with the resonator; a control chip packaging step: mounting a control chip at the corresponding position of the packaging surface, the control chip is directly electrically connected to the conductive block of the resonator through an electroplated column on the one hand, and is electrically connected to the circuit of the thermistor through an interconnection layer on the other hand. The invention stacks the ceramic resonator and the plastic package body to form a crystal oscillator heterogeneous stacking structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor packaging, and in particular relates to a semiconductor packaging structure, a device and a packaging process thereof. Background Art

[0002] Semiconductor packaging refers to the entire process of assembling qualified semiconductor chips, components, etc. onto a carrier, using appropriate connection technology to form electrical connections, installing the casing, etc., to ultimately form an effective component. The crystal oscillator (referred to as the crystal body) also requires the use of packaging technology during the production process.

[0003] Crystal oscillators can be divided into many types according to their materials. Quartz crystal oscillators are a kind of high-efficiency and high-stability oscillator, which is widely used in various oscillation circuits such as color TVs, computers, remote controls, and communication systems. They are used for frequency generators, generate clock signals for data processing equipment, and provide reference signals for specific systems. Crystal oscillators are formed by packaging a crystal resonator and a control chip together and electrically connecting them. The crystal oscillator can be packaged in ceramic or metal packaging methods. Different types of crystal oscillators are required in different circuit systems.

[0004] The existing crystal oscillator packaging uses the same packaging material for the resonator part and the control chip part (i.e. homogeneous packaging), and ceramic packaging is more widely used than metal packaging because the ceramic base has excellent mechanical properties and stability, can support the crystal, protect the crystal, and reduce vibration attenuation. The cost is lower than that of metal packaging. The current crystal oscillator ceramic base can be an integrally formed special-shaped ceramic, such as H-shaped. The resonator wafer and the control chip are respectively mounted on the corresponding areas of the ceramic base to finally form a ceramic crystal oscillator. There is also a base formed by stacking and sintering multiple layers of ceramic plates. Circuit routing and electrodes need to be arranged inside the ceramic, and the production cost of the ceramic base is higher than that of ordinary packaging. The ceramic wall thickness needs to be set to a certain level to meet the requirements of stable mechanical properties. Otherwise, the ceramic base is easily damaged, resulting in a larger overall volume of the crystal oscillator. The wall thickness limits space utilization and causes space waste. The airtightness of the crystal oscillator is crucial, but the existing crystal oscillator is covered with a metal cover on the crystal chamber. After the crystal oscillator is sealed and welded, the interior is evacuated and filled with nitrogen. The metal cover has no other protection and is easily corroded by long-term exposure, which affects the airtightness and causes the crystal oscillator to fail. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a semiconductor packaging structure, a device and a packaging process thereof.

[0006] To achieve the above object, the present invention provides a semiconductor packaging process, comprising the following steps:

[0007] Resonator packaging step: providing a substrate, on which a plurality of ceramic resonators are evenly inverted, the bottom surface of the resonator is exposed, the front surface of the resonator is completely encapsulated to ensure airtightness, mounting a conductive block at the exposed bottom electrode pad position, plastic-sealing the resonator, and horizontally grinding the packaging surface until the top surface of the conductive block is exposed;

[0008] Thermistor packaging step: mounting a thermistor at the corresponding position of each resonator on the polished packaging surface, and the thermistor is electrically connected to the conductive block through the electroplated circuit, thereby achieving electrical connection with the resonator;

[0009] Control chip packaging step: mounting the control chip at the corresponding position of the packaging surface, the control chip is electrically connected to the conductive block of the resonator directly through the electroplated pillars on one hand, and is electrically connected to the circuit of the thermistor through the interconnection layer on the other hand, and the lead-out terminals are electroplated, and the electrically connected redistribution layer is electroplated on the lead-out terminals to adjust the layout of the lead-out terminals, and at the same time increase the distance from the control chip to the package surface, and the top surface of the redistribution layer is exposed by plastic sealing and grinding;

[0010] Product unitization steps: peel off the substrate and vertically cut in the cutting area to form product units. Each product unit is a crystal oscillator with a ceramic resonator and a plastic package. The resonator, thermistor and control chip are stacked in sequence with plastic packaging materials and electrically connected. The control chip controls the resonator and thermistor to form a temperature-compensated semiconductor packaging structure.

[0011] Furthermore, in the resonator packaging step, the resonator includes a base, a crystal plate is arranged in the middle cavity of the base, the crystal plate is electrically connected to the bottom electrode pad of the resonator through the line in the base wall, the top of the base is covered with a metal cover, and the metal cover and the base body are welded together through a seam sealing.

[0012] Furthermore, in the resonator packaging step, a plurality of resonators are evenly arranged on the upper surface of the substrate and encapsulated as a whole, and after the encapsulation material is peeled off, it is turned upside down on the substrate, at which time the bottom electrode pads of the plurality of resonators are flush with the encapsulation material and exposed.

[0013] Furthermore, in the thermistor packaging step, a first connecting column for electrical interconnection is electroplated on a portion of the top surface of the conductive block exposed on the packaging surface, and a film block A is adhered to the top surface of another portion of the conductive block. After the thermistor is mounted, the thermistor, the first connecting column and the top surface of the film block A are exposed by grinding after plastic sealing.

[0014] Furthermore, in the thermistor packaging step, the circuit is electroplated and connected between the exposed thermistor and the first connecting column, the exposed top surface of the film block A continues to adhere to the film block B of the same height as the circuit, and the packaging surface is further plastic-sealed and ground to expose the top surface of the circuit and the film block B that is coplanar.

[0015] Furthermore, in the control chip packaging step, a second connecting column is electroplated on the top surface of the circuit exposed by grinding, and a film block C is adhered to the top surface of the film block B. After the control chip is mounted, the control chip, the second connecting column and the film block C are plastic-sealed and ground to expose the coplanar top surface of the three.

[0016] Furthermore, the control chip packaging step also includes a film stripping and electroplating step, etching and removing film block A, film block B and film block C to form a plating tank, forming a column by electroplating in the plating tank, and electrically connecting the column to the control chip by electroplating, and the electroplated interconnect layer electrically connects the second connecting column and the control chip, thereby realizing the electrical connection of the control chip and the thermistor circuit.

[0017] Furthermore, in the product unitization step, before cutting into product units, external solder pins electrically connected to the redistribution layer are electroplated on the packaging surface.

[0018] A semiconductor packaging structure, comprising:

[0019] A resonator, wherein the resonator is a ceramic package, a conductive block is mounted on the electrode pad at the bottom of the resonator, and the front side of the resonator is completely encapsulated to ensure airtightness;

[0020] A plastic package, wherein a thermistor and a control chip are encapsulated in the plastic package, and the thermistor is electrically connected to the conductive block through a circuit electroplated in the plastic package, thereby achieving electrical connection with the resonator;

[0021] The control chip is electrically connected to the conductive block of the resonator directly through the electroplated pillars on the one hand, and is electrically connected to the circuit of the thermistor through the interconnection layer on the other hand. On the other hand, the layout of the lead-out terminals is adjusted by electroplating the lead-out terminals and the redistribution layer electrically connected is electroplated on the lead-out terminals, so as to increase the distance between the control chip and the package surface;

[0022] The plastic package body and the ceramic resonator form a heterogeneous stacked crystal oscillator. The resonator, thermistor and control chip are stacked in sequence with plastic package materials in between and are electrically connected. The control chip controls the resonator and thermistor to form a temperature-compensated semiconductor packaging structure.

[0023] Furthermore, the resonator includes a base, a crystal plate is arranged in the middle cavity of the base, the crystal plate is electrically connected to the electrode pad at the bottom of the resonator through the line in the base wall, the top of the base is covered with a metal cover, and the metal cover and the base body are welded together through a seam sealing.

[0024] Furthermore, a first connecting column for electrical interconnection is electroplated on a portion of the top surface of the conductive block, and a film block A is adhered on another portion of the top surface of the conductive block, and the top surfaces of the thermistor, the first connecting column and the film block A are coplanar.

[0025] Furthermore, the circuit is connected between the thermistor and the first connection column by electroplating, and a film block B having the same height as the circuit is continuously adhered to the top surface of the film block A.

[0026] Furthermore, the top surface of the circuit is plated with a second connecting column, and a film block C is adhered to the top surface of the film block B, and the top surfaces of the control chip, the second connecting column and the film block C are coplanar.

[0027] Furthermore, membrane block A, membrane block B and membrane block C are etched away to form an electroplating tank, and pillars are formed by electroplating in the electroplating tank. The pillars are electrically connected to the control chip by electroplating, and the interconnection layer electrically connects the second connecting pillar and the control chip, thereby realizing the electrical connection of the control chip and the thermistor circuit.

[0028] Furthermore, one surface of the plastic package body is electroplated with an external soldering foot electrically connected to the redistribution layer.

[0029] The present invention: 1. The ceramic resonator and the plastic package are heterogeneously stacked to form a crystal oscillator structure, which replaces the existing homogeneous crystal oscillator body, effectively avoiding the occurrence of damage to the product appearance due to stress concentration, and extending the service life of the product;

[0030] 2. The method of making a crystal oscillator body by performing advanced packaging technology on a ceramic base to form a heterogeneous stack can greatly save costs, improve the qualified rate and efficiency of product production, simplify the process and improve the product performance, break through the limitation of the ceramic base wall thickness on space utilization, and can mount a larger size and a stronger processing power control chip;

[0031] 3. The resonator is placed forward on the substrate and then encapsulated, peeled off, and inverted. After the process is completed, the metal cover is also encapsulated with plastic. The metal cover is protected by the encapsulation material and is not easily corroded even after long-term exposure, thereby ensuring the overall airtightness and preventing the crystal oscillator from failing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 One of the cross-sectional views of a resonator packaging step of a semiconductor packaging process of the present invention;

[0033] Figure 2 The second cross-sectional view of a resonator packaging step of a semiconductor packaging process of the present invention;

[0034] Figure 3 The third cross-sectional view of a resonator packaging step of a semiconductor packaging process of the present invention;

[0035] Figure 4 The fourth cross-sectional view of a resonator packaging step of a semiconductor packaging process of the present invention;

[0036] Figure 5 One of the cross-sectional views of a thermistor packaging step of a semiconductor packaging process of the present invention;

[0037] Figure 6 The second cross-sectional view of the thermistor packaging step of a semiconductor packaging process of the present invention;

[0038] Figure 7 The third cross-sectional view of the thermistor packaging step of a semiconductor packaging process of the present invention;

[0039] Figure 8 The fourth cross-sectional view of the thermistor packaging step of a semiconductor packaging process of the present invention;

[0040] Fig. 9 One of the cross-sectional views of a control chip packaging step of a semiconductor packaging process of the present invention;

[0041] Fig.10 The second cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0042] Fig.11 The third cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0043] Fig.12 The fourth cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0044] Fig.13 The fifth cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0045] Fig.14 The sixth cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0046] Fig.15 The seventh cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0047] Fig.16 The eighth cross-sectional view of a control chip packaging step of a semiconductor packaging process of the present invention;

[0048] Fig.17 One of the cross-sectional views of a product unitization step of a semiconductor packaging process of the present invention;

[0049] Fig.18 The second cross-sectional view of a product unitization step of a semiconductor packaging process of the present invention;

[0050] Fig.19The third cross-sectional view of a product unitization step of a semiconductor packaging process of the present invention;

[0051] Fig. 20 The fourth cross-sectional view of a product unitization step of a semiconductor packaging process of the present invention;

[0052] Fig.21 It is a schematic diagram of a semiconductor packaging structure of the present invention.

[0053] In the figure: 1. resonator; 2. thermistor; 3. first connecting column; 4. membrane block A; 5. circuit; 6. membrane block B; 7. control chip; 8. membrane block C; 9. second connecting column; 10. electroplating tank; 11. column; 12. interconnect layer; 13. lead end; 14. redistribution layer; 15. plastic package. DETAILED DESCRIPTION

[0054] The content of the present invention will be explained below in conjunction with specific embodiments, examples of which are shown in the accompanying drawings, wherein the same or similar numbers throughout represent the same or similar components or components with the same or similar functions.

[0055] The directional terms mentioned in the present invention, such as: up, down, left, right, front, back, inside, outside, front, back, side, etc., are only reference directions of the drawings. The embodiments described below with reference to the drawings and the directional terms used are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention. In addition, the various specific process and material examples provided in the present invention are all those skilled in the art who can recognize the application of other processes and / or the use of other materials.

[0056] The resonator 1 of the crystal refers to a thin slice (referred to as a wafer or crystal slice) cut from a crystal at a certain azimuth angle, and a metal layer is coated on its two corresponding surfaces as electrodes. A lead is welded on each electrode and connected to the pin of the base to form the resonator 1 part. Then the chip is installed on the base. The chip is electrically connected to the resonator 1 through the pins. The electrical properties of the chip also extend to the outside of the base. The base constitutes a homogeneous packaging shell and finally becomes a crystal oscillator. The crystal oscillator uses a crystal that can convert electrical energy and mechanical energy into each other and works in a resonant state to provide stable and accurate single-frequency oscillation. There are many types of crystal oscillators, such as clock crystal oscillators.

[0057] In order to better understand the purpose, structure and function of the present invention, the following Figure 1 -Attached Fig.21 , a semiconductor packaging structure, device and packaging process proposed by the present invention are further described in detail.

[0058] Please see attached Figure 1 -Attached Fig. 20 The semiconductor packaging process comprises the following steps:

[0059] Resonator 1 packaging step: providing a substrate, on which a plurality of ceramic resonators 1 are evenly inverted, the bottom surface of the resonator 1 is exposed, the front surface of the resonator 1 is completely encapsulated to ensure airtightness, mounting a conductive block at the exposed bottom electrode pad position, plastic-sealing the resonator 1, and horizontally grinding the packaging surface until the top surface of the conductive block is exposed;

[0060] Thermistor 2 packaging step: mounting thermistor 2 at the corresponding position of each resonator 1 on the polished packaging surface, thermistor 2 is electrically connected to the conductive block through the electroplated circuit, thereby achieving electrical connection with the resonator 1;

[0061] Control chip 7 packaging step: mounting control chip 7 at the corresponding position of the packaging surface, the control chip 7 is electrically connected to the conductive block of the resonator 1 directly through the electroplated pillar 11 on the one hand, and is electrically connected to the circuit 5 of the thermistor 2 through the interconnection layer 12 on the other hand, and the lead-out terminal 13 is electroplated, and the electrically connected redistribution layer 14 is electroplated on the lead-out terminal 13 to adjust the layout of the lead-out terminal 13, and at the same time increase the distance between the control chip 7 and the package surface, and the top surface of the redistribution layer 14 is exposed by plastic sealing and grinding;

[0062] Product unitization step: peel off the substrate and vertically cut in the cutting area to form product units. Each product unit is a heterogeneously stacked crystal oscillator consisting of a ceramic resonator 1 and a plastic package 15. The resonator 1, thermistor 2 and control chip 7 are stacked in sequence with plastic packaging materials and electrically connected. The control chip 7 controls the resonator 1 and thermistor 2 to form a temperature-compensated semiconductor packaging structure.

[0063] Please see the attached Figure 1 -Attached Figure 4 In the steps of packaging the resonator 1, a substrate is provided. The substrate is a commonly used substrate type in the art, and can be a glass substrate, a resin plate, or other suitable materials. The substrate provides a support platform for each process step. First, a plurality of resonators 1 (such as the attached) are evenly placed on the upper surface of the substrate. Figure 1 As shown), the resonator 1 is encapsulated as a whole and cured (as shown in the attached Figure 2As shown), after stripping off the encapsulation material, it is turned upside down on the substrate. At this time, the bottom electrode pads of multiple resonators 1 are flush with the encapsulation material and exposed, that is, multiple ceramic resonators 1 are evenly inverted on the substrate. Resonator 1 is the simplest oscillation circuit without any compensation. Resonator 1 needs to be electrically connected to a semiconductor chip with a built-in oscillation circuit that matches its specifications and functions to form a loop, thereby forming a crystal oscillator with a control function (referred to as crystal body or crystal oscillator). Resonator 1 is a ceramic package, and its structure is a common structure in the technical field. The structure includes a base, a crystal piece is arranged in the cavity in the middle of the base, and the crystal piece is electrically connected to the bottom electrode pad of the resonator 1 (the pin of the base) through a line in the base wall. The top of the base is covered with a metal cover, and the metal cover and the base body are welded together through a seam seal, and the metal cover is brought into contact with the substrate to invert the resonator 1 on the substrate (as shown in the attached Figure 2 As shown in FIG. 1 ), after being inverted, the bottom surface of the resonator 1 is exposed, and there is an electrode pad on the bottom surface, and a conductive block (as shown in FIG. 1 ) is mounted on the electrode pad. Figure 3 As shown in the figure, the conductive block is not marked in the figure), the electrode pad is raised to prevent grinding from damaging the base of the ceramic package resonator 1, the plastic package resonator 1 is polished by horizontal mechanical grinding until the top surface of the conductive block is exposed (as shown in the attached figure). Figure 4 as shown).

[0064] Please see the attached Figure 5 -Attached Figure 8 The step of packaging thermistor 2 includes mounting thermistor 2 on the ground packaging surface, mounting a thermistor 2 on the corresponding position of each resonator 1, electroplating the first connecting column 3 for electrical interconnection on the top surface of a portion of the conductive block exposed on the packaging surface, and adhering the film block A4 (such as the attached film) on the top surface of the other portion of the conductive block. Figure 5 As shown in the figure, after the thermistor 2 is mounted, the thermistor 2, the first connecting column 3 and the top surface of the film block A4 are on the same horizontal plane. After the thermistor 2 is mounted, the top surface of the thermistor 2, the first connecting column 3 and the film block A4 are exposed by horizontal mechanical grinding (as shown in the figure). Figure 6 As shown in FIG. 1 ), a circuit 5 is electroplated between the exposed thermistor 2 and the first connecting column 3, and the thermistor 2 is electrically connected to the conductive block through the electroplated circuit 5, thereby achieving electrical connection with the resonator 1, and a film block B6 (as shown in FIG. 1 ) having the same height as the circuit is continuously adhered to the top surface of the exposed film block A4. Figure 7 As shown in the figure), continue to plastic encapsulate and horizontally mechanically grind the package surface until the top surface coplanar with the circuit 5 and the film block B6 is exposed (as shown in the figure). Figure 8 As shown in FIG. 1 ), the thermistor 2 is electrically connected to the resonator 1 through the circuit 5 and the conductive block, and provides a temperature compensation function according to changes in ambient temperature.

[0065] Please see the attached Fig. 9 -Attached Fig.16In the step of packaging the control chip 7, the control chip 7 is mounted on the corresponding position of the top surface where the circuit 5 and the film block B6 are coplanar with each other after horizontal mechanical grinding. The front side of the control chip 7 can be mounted upward (that is, the output end of the control chip 7 faces upward, and the back side of the control chip 7 is mounted on the packaging surface) (see the attached figure). Fig. 9 As shown) or mounted with the front side facing down (that is, the output end of the control chip 7 is mounted on the packaging surface with the output end facing down, and the back side of the control chip 7 is facing up). The present invention takes the mounting of the control chip 7 with the front side facing up as an example. The control chip 7 is mounted above the thermistor 2. After the mounting is completed, a second connecting column 9 is electroplated on the exposed top surface of the circuit 5. The second connecting column 9 and the first connecting column 3 are stacked and connected with each other through one end of the circuit 5, and the bottom area of ​​the second connecting column 9 is smaller than the bottom area of ​​the first connecting column 3. The bottom area of ​​the first connecting column 3 is smaller than the bottom area of ​​the conductive block of the resonator 1. The first connecting column 3, the second connecting column 9, the circuit 5 and the conductive block constitute the temperature compensation control connection circuit of the resonator 1, the thermistor 2 and the control chip 7. The contact area between the two connecting columns and the encapsulation material is increased, and a card connection is formed between the connecting columns of different sizes and the encapsulation material to avoid the occurrence of a disconnection or short circuit caused by a fault caused by multi-layer electroplating, and the structure is stable.

[0066] Continue to adhere film block C8 (such as attached) to the top surface of film block B6 exposed by grinding. Fig.10 As shown in the figure, the top surface of the film block C8 is coplanar with the top surface of the second connecting pillar 9. The film blocks A4, B6 and C8 stacked and adhered to each other have the same shape and structure, and only have different heights. After being adhered and stacked, they are integrated. After further encapsulation and curing, horizontal mechanical grinding is performed to expose the top surface of the film block C8 and the top surface of the second connecting pillar 9 (as shown in the figure). Fig.11 As shown), at this time, the output end of the control chip 7 is also exposed by grinding. The membrane block A4, the membrane block B6 and the membrane block C8 are made of materials that can be peeled off or dissolved in a simple way, such as photocurable hydrogel and pyrolysis adhesive. The hydrogel is a water-soluble polymer with a network cross-linked structure. A part of hydrophobic groups and hydrophilic residues are introduced into the hydrogel. The hydrophilic residues combine with water molecules to connect the water molecules inside the network, and the hydrophobic residues swell in water. The cross-linked polymer, add a photoinitiator to the hydrogel stock solution, the photoinitiator is an important component, and fully stir to make the photoinitiator uniformly dispersed in the hydrogel stock solution. Turn on the ultraviolet light irradiation, control the irradiation intensity and time, and initiate the curing reaction of the hydrogel to form the membrane block A4, the membrane block B6 and the membrane block C8. The hydrogel can be removed by placing it in water and heating it, and there is less residue; the pyrolysis adhesive is a solvent-based adhesive, which has a certain adhesive force at room temperature and can play a role in positioning and supporting. As long as the temperature is heated to the set temperature, the adhesive force will disappear, and it can be simply peeled off, with less residue and no pollution to the adherend.

[0067] According to the selected materials of the film block A4, the film block B6 and the film block C8, the peeling and removing method is selected accordingly. If the light-curing hydrogel is selected, the plastic package is placed in water and heated to remove; if the thermal decomposition glue is selected, the adhesive force of the plastic package disappears after the plastic package is heated to the set temperature, and the electroplating tank 10 (such as the attached Fig.12 As shown in the figure, since the shapes and structures of the stacked and adhered film blocks A4, B6 and C8 are the same, only the heights are different, and there is less residue after peeling, the inner wall of the electroplating tank 10 is smooth and continuous, which is convenient for the electroplating process. Fig.13 As shown in the figure), by repeatedly adhering the film blocks and then peeling them off and electroplating them, the electroplating becomes a continuous whole, replacing the process of multiple direct electroplating stacking. It effectively prevents the grinding stress caused by the grinding of the package surface during the grinding stage, which causes the electroplating part to fall off. At the same time, it also prevents the multi-layer electroplating stack from breaking and disconnecting. The structure and performance of the product are stable.

[0068] While electroplating the pillar 11, an interconnection layer 12 is electroplated between the top surface of the second connection pillar 9 and a portion of the output end exposed by the control chip 7 to achieve electrical connection. Another portion of the output end of the control chip 7 is directly electrically connected to the conductive block of the resonator 1 through the electroplated pillar 11, and a lead-out terminal 13 (as shown in the attached figure) is electroplated on another portion of the output end of the control chip 7. Fig.13 As shown in FIG. 1 ), the lead-out terminal 13 is encapsulated, the interconnection layer 12 and the pillar 11 are also encapsulated, and the top surface of the lead-out terminal 13 is exposed by horizontal mechanical grinding on the encapsulation surface (as shown in FIG. 1 ). Fig.14 and electroplating an electrically connected redistribution layer 14 on the top surface of the lead-out terminal 13 (as shown in the attached Fig.15 ), to adjust the layout of the lead-out terminals 13, keep the adjacent lead-out terminals 13 at an appropriate distance, prevent the lead-out terminals 13 from being too small or too large to cause short circuit or disconnection during subsequent line connection, and encapsulate and grind the top of the exposed redistribution layer 14 (as shown in the attached Fig.16 As shown), at the same time, by electroplating the redistribution layer 14 on the lead-out terminal 13, and then further encapsulating and grinding the redistribution layer 14 to expose the top of the redistribution layer 14, the distance from the control chip 7 to the package surface is increased. The plastic encapsulation layer there can strengthen the mechanical buffer layer, buffer the concentrated stress, and avoid damage to the product appearance; it also increases the thermal resistance and isolates the ambient heat in the welding area from being directly transferred to the control chip 7, thereby ensuring the normal operation of the control chip 7. The top serves as an electrical port for the crystal oscillator packaging structure to be connected to the outside.

[0069] Please see the attached Fig.17 -Attached Fig. 20In the product unitization step, the substrate can be removed by mechanical stripping. At this time, the packaging process has been completed, and it only needs to be cut into product units. The resonator 1 is placed forward on the substrate and then encapsulated, stripped, and inverted. After the process is completed, the metal cover is also encapsulated with plastic. The metal cover is protected by the encapsulation material and is not easily corroded by long-term exposure, thereby ensuring the overall airtightness, preventing the crystal oscillator from failing, and ensuring the formation of a heterogeneous stack of the ceramic base resonator 1 and the plastic encapsulation body 15 of the crystal oscillator structure. In the initial stage of product design, the position and size of each structure are set, and a suitable safety area is reserved between adjacent product units. The safety area extends vertically to the encapsulation surface. The position and size of each structure in the process step do not exceed the safety area. Regarding the setting of cutting paths in the safety area (such as the attached Fig.17 As shown by the vertical line in the middle, all the attached drawings are cross-sectional views, showing only part of the cutting path in one direction, i.e., the horizontal cutting path, while the vertical cutting path and other parts of the horizontal cutting path are blocked), and the whole package is cut horizontally and vertically along the cutting path to form a product unit (such as the attached Fig.18 As shown), each product unit is a heterogeneously stacked crystal oscillator of a ceramic resonator 1 and a plastic package 15. The resonator 1, thermistor 2 and control chip 7 are stacked in sequence with plastic packaging materials in between and are electrically connected. The spatial stacking is reasonable, space is saved, and the size is small. The control chip 7 controls the resonator 1 and thermistor 2 to form a temperature-compensated semiconductor packaging structure.

[0070] In order to realize the specific functions and design purposes of the product unit, the product unit needs to be welded to the corresponding external circuit system. Typically, it is connected to the printed circuit board (PCB) using welding technology. The reliability of welding has an important impact on the performance of the product unit, so it is necessary to detect and analyze the welding effect. Automatic optical inspection (AOI) is often used to detect the welding effect. The appearance contour of the product unit after welding, such as tin creeping, is used to determine whether there are problems such as cold soldering, warping, and broken soldering. Tin creeping refers to the coating of solder paste on the electrical port of the product. After inverted welding, the tin paste climbs a certain height from the side of the product. However, in the crystal oscillator packaging structure of the present invention, its externally connected electrical port is flush with the package cover, and the exposed area is limited. Moreover, the port is located in the middle of the package cover. After the solder is coated, the tin paste is difficult to extend to the edge of the product, and it is even more difficult to climb along the side of the product. Tin creeping is not obvious, and it is difficult to judge the welding effect. Therefore, further, before the product unitization step, the present invention can electroplate the external solder feet (such as attached) on the top of the exposed redistribution layer 14. Fig.19 As shown), the product unit is welded in the working area through the external welding feet. The external welding feet have a height set according to the actual product needs, and the shape and size can be flexibly set by electroplating. After welding through the external welding feet, tin creep is obvious.

[0071] The side of the plastic package 15 can be further cut so that the side of the resonator 1 is coplanar with the side of the plastic package 15 (as shown in the attached figure). Fig. 20 As shown), the heterogeneous stacked structure of the crystal oscillator is more prominent, and the product volume is further reduced. Alternatively, in the cutting step, a wider cutting knife is used to directly cut along the side edge of the resonator 1 at one time. To avoid cutting and damaging the resonator 1 on the ceramic base, a thinner plastic packaging material is still required to be retained on the side of the resonator 1, and the plastic packaging material is still retained at the metal cover position on the top surface of the resonator 1.

[0072] In order to further simplify the packaging process and improve the production efficiency of crystal oscillator products, the entire continuous packaging process can be divided into the packaging of the resonator 1 and the packaging of the lower plastic package 15. The two parts are then mounted and electrically connected together to form the heterogeneous stacked crystal oscillator structure of the present invention.

[0073] The heterogeneous stacking of the ceramic resonator 1 and the plastic package 15 forms a crystal oscillator structure, replacing the existing homogeneous crystal oscillator body. The ceramic base has excellent mechanical properties and stability, can support the crystal and reduce vibration attenuation, and the resonator 1 is the core of the vibration. In order to ensure its normal working state, the ceramic base package is still used, but the control chip 7 is partially packaged with plastic package. After the product is welded to the working area, it replaces the rigid package, which can buffer the mechanical stress transmitted by the surrounding environmental factors and the mechanical stress transmitted back by the resonator frequency vibration, effectively avoiding the occurrence of stress concentration causing damage to the product appearance, and extending the service life of the product. In addition, the method of forming a crystal oscillator body by performing advanced packaging technology on the ceramic base to form a heterogeneous stack, compared with the existing crystal oscillator body made by homogeneous sintering processing, greatly saves costs, improves the qualified rate and efficiency of product production, simplifies the process and is efficient, and has excellent product performance. It breaks through the limitation of the ceramic base wall thickness on space utilization and can mount a larger size and more powerful control chip 7.

[0074] The resonator 1, thermistor 2 and control chip 7 are stacked in sequence with plastic packaging materials and electrically connected. The control chip 7 controls the resonator 1 and thermistor 2 to form a temperature-compensated semiconductor packaging structure (crystal oscillator). Thermistor 2 senses the ambient temperature, and the resistance value changes with the temperature. The signal is transmitted to the control chip 7. The control chip 7 controls the output frequency of the resonator 1 after appropriate transformation of the temperature information, and adjusts the deviation of the compensation oscillation frequency to achieve the effect of stabilizing the output frequency. Through the connection control of thermistor 2, control chip 7 and resonator 1, the traditional analog temperature compensation (TCXO) and single-chip temperature compensation are replaced. The temperature compensation network of the compensation (MCXO) further reduces the production cost of the product and meets the general use requirements. Analog temperature compensation is achieved by using analog devices, that is, by changing analog devices such as the load capacitor in the oscillation circuit to make it change with temperature to compensate for the frequency drift of the crystal resonator due to changes in ambient temperature. The structure and compensation circuit are complex and the cost is high. The microcontroller temperature compensation can realize automatic temperature compensation of the crystal oscillator, so that the frequency stability of the crystal oscillator is very high and can adapt to a wider operating temperature range, but the specific compensation circuit is more complex and the cost is higher. It is only suitable for base stations and radio stations that require high precision.

[0075] Through the above semiconductor packaging process, a semiconductor packaging structure (such as the attached Fig.21 As shown), the structure includes:

[0076] Resonator 1, resonator 1 comprises a base, a crystal plate is arranged in a cavity in the middle of the base, the crystal plate is electrically connected to the electrode pad at the bottom of resonator 1 through a line in the base wall, the top of the base is covered with a metal cover, the metal cover and the base body are welded together through a seam sealing, resonator 1 is a ceramic package, a conductive block is mounted on the electrode pad at the bottom of resonator 1, and the front of resonator 1 is completely encapsulated to ensure airtightness;

[0077] The plastic package 15 contains a thermistor 2 and a control chip 7. The thermistor 2 is electrically connected to the conductive block through a circuit 5 electroplated inside the plastic package 15, thereby realizing electrical connection with the resonator 1. That is, a first connecting column 3 electrically interconnected is electroplated on the top surface of a portion of the conductive block, and a film block A4 is adhered to the top surface of another portion of the conductive block. The thermistor 2, the first connecting column 3 and the top surface of the film block A4 are coplanar. The circuit 5 is electroplated and connected between the thermistor 2 and the first connecting column 3. The film block A4 is further adhered to the top surface of the conductive block A4. The circuit 5 has a membrane block B6 of the same height, the second connecting pillar 9 is electroplated on the top surface of the circuit 5, the membrane block C8 is adhered to the top surface of the membrane block B6, the control chip 7, the second connecting pillar 9 and the top surface of the membrane block C8 are coplanar, the membrane block A4, the membrane block B6 and the membrane block C8 are etched away to form an electroplating tank 10, and the pillar 11 is formed by electroplating in the electroplating tank 10, and the pillar 11 is electrically connected to the control chip 7 by electroplating, and the interconnection layer 12 electrically connects the second connecting pillar 9 and the control chip 7, so as to realize the electrical connection between the control chip 7 and the circuit 5 of the thermistor 2;

[0078] The control chip 7 is electrically connected to the conductive block of the resonator 1 directly through the electroplated pillars 11, and is electrically connected to the circuit 5 of the thermistor 2 through the interconnection layer 12. The lead-out terminals 13 are electroplated, and the electrically connected redistribution layer 14 is electroplated on the lead-out terminals 13 to adjust the layout of the lead-out terminals 13 and increase the distance between the control chip 7 and the package surface.

[0079] The plastic package 15 and the ceramic resonator 1 form a heterogeneous stacked crystal oscillator. The resonator 1, thermistor 2 and control chip 7 are stacked in sequence with plastic package material in between and are electrically connected. The control chip 7 controls the resonator 1 and thermistor 2 to form a temperature-compensated semiconductor packaging structure.

[0080] An external soldering pin electrically connected to the redistribution layer 14 is plated on one surface of the plastic package body 15 .

[0081] In the present invention, a ceramic resonator 1 and a plastic package body 15 are heterogeneously stacked to form a crystal oscillator structure, which replaces the existing homogeneous crystal oscillator body, effectively avoiding the occurrence of damage to the product appearance due to stress concentration, and extending the service life of the product. In addition, the method of forming a crystal oscillator body by performing an advanced packaging process on a ceramic base to form a heterogeneous stack can greatly save costs, improve the qualified rate and efficiency of product production, and simplify the process. The process is efficient and the product performance is excellent. The limitation of the wall thickness of the ceramic base on space utilization has been broken through, and a control chip 7 with a larger size and stronger processing capability can be mounted. The resonator 1 is placed forward on the substrate and then encapsulated, peeled off, and inverted. After the process is completed, the metal cover is also encapsulated by the plastic package material. The metal cover is protected by the encapsulation material and is not easily corroded by long-term exposure, thereby ensuring the overall airtightness and preventing the crystal oscillator from failing.

[0082] All the steps of the electroplating process of the present invention are to first form electroplating protection on the surface through exposure and development photolithography technology, and then form a metal seed layer in the area to be electroplated by sputtering or copper deposition or other appropriate methods. The metal seed layer is made of copper or other metal materials. The metal seed layer is to ensure the bonding force between the subsequent electroplated metal and the encapsulation material, and at the same time provide a surface for the electroplating to attach conductive ions to ensure the electroplating effect. The entire steps in the electroplating process and the materials used are also technical common sense in this field.

[0083] All steps of the packaging process of the present invention are to form a package by injection molding of plastic packaging materials in combination with other reasonable packaging methods such as molding. The packaging materials used in the present invention can be epoxy resin (expoxyresin), cyanate (cyanate ester), polyimide (Polyimide), etc., which have low cost and good curing performance. The packaging process plays an important role in the field of semiconductor manufacturing, mainly in terms of protection, connection, support, reliability and promotion of technological progress. The protection function refers to the ability of the packaging to protect the internal components of the packaging material from mechanical damage, moisture, dust and other external environmental factors, ensuring the normal operation of the internal components of the packaging material under extreme environments; the connection function refers to the ability of the packaging to connect the internal components of the packaging material with other electronic components, so that the internal components of the packaging material can be installed and used on the circuit board; the support function refers to the ability of the packaging to fix the internal components of the packaging material while supporting the internal components of the packaging material to prevent damage; reliability refers to the increasingly high reliability requirements for packaging materials and processes, so as to ensure that the internal components of the packaging material can operate normally under various extreme environments.

[0084] After the package cutting, a series of operations need to be carried out, such as finished product testing after the package is completed. Usually, it goes through the processes of incoming inspection, testing and packaging, and finally it is put into storage and shipped.

[0085] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are within the scope of protection of the present invention.

Claims

1. A semiconductor packaging process, characterized in that: The following steps are involved: Resonator packaging step: providing a substrate, on which a plurality of ceramic resonators are evenly inverted, the bottom surface of the resonator is exposed, the front surface of the resonator is completely encapsulated to ensure airtightness, mounting a conductive block at the exposed bottom electrode pad position, plastic-sealing the resonator, and horizontally grinding the packaging surface until the top surface of the conductive block is exposed; Thermistor packaging steps: electroplating a first connecting column for electrical interconnection on a portion of the top surface of the conductive block exposed on the packaging surface, and adhering a film block A on another portion of the top surface of the conductive block, and mounting a thermistor at a corresponding position of each resonator on the ground packaging surface at the same time, and after mounting the thermistor, plastic-sealing and grinding to expose the top surface of the thermistor, the first connecting column and the film block A, electroplating and connecting the circuit between the exposed thermistor and the first connecting column, and adhering a film block B of the same height as the circuit to the exposed top surface of the film block A, and continuing to plastic-seale and grind the packaging surface to expose the top surface of the circuit and the film block B, and the thermistor is electrically connected to the conductive block through the electroplated circuit, thereby achieving electrical connection with the resonator; Control chip packaging step: mounting the control chip at the corresponding position of the packaging surface where the circuit and the top surface of the film block B are exposed by grinding, electroplating the second connecting column on the top surface of the circuit exposed by grinding, adhering the film block C on the top surface of the film block B, and after mounting the control chip, plastic-sealing the control chip, the second connecting column and the film block C and grinding to expose the top surface of the three being coplanar; This step also includes a film stripping and electroplating step, wherein the film block A, the film block B and the film block C are etched and removed to form an electroplating tank, a column is formed by electroplating in the electroplating tank, and the column is electrically connected to the control chip by electroplating, and the electroplated interconnection layer electrically connects the second connection column and the control chip, thereby realizing the electrical connection of the control chip and the thermistor circuit. On the one hand, the control chip is directly electrically connected to the conductive block of the resonator through the electroplated column, and on the other hand, it is electrically connected to the thermistor circuit through the interconnection layer, and on the other hand, the lead-out terminal is electroplated, and the electrically connected redistribution layer is electroplated on the lead-out terminal, and the top surface of the redistribution layer is exposed by plastic sealing and grinding to adjust the layout of the lead-out terminal, and at the same time, the distance from the control chip to the package surface that exposes the top surface of the redistribution layer is increased; Product unitization steps: peel off the substrate and vertically cut in the cutting area to form product units. Each product unit is a crystal oscillator with a ceramic resonator and a plastic package. The resonator, thermistor and control chip are stacked in sequence with plastic packaging materials and electrically connected. The control chip controls the resonator and thermistor to form a temperature-compensated semiconductor packaging structure.

2. The semiconductor packaging process according to claim 1, characterized in that: In the resonator packaging step, the resonator includes a base, a crystal plate is arranged in the middle cavity of the base, the crystal plate is electrically connected to the electrode pad at the bottom of the resonator through the line in the base wall, the top of the base is covered with a metal cover, and the metal cover and the base body are welded together through a seam sealing.

3. The semiconductor packaging process according to claim 2, characterized in that: In the resonator packaging step, a plurality of resonators are evenly arranged on the upper surface of the substrate and encapsulated as a whole, and after the encapsulation material is peeled off, it is turned upside down on the substrate, at which time the bottom electrode pads of the plurality of resonators are flush with the encapsulation material and exposed.

4. The semiconductor packaging process according to claim 1, characterized in that: In the product unitization step, before being cut into product units, external solder pins electrically connected to the redistribution layer are electroplated on the packaging surface.

5. A semiconductor packaging structure, characterized in that: Included are: A resonator, wherein the resonator is a ceramic package, a conductive block is mounted on the electrode pad at the bottom of the resonator, and the front side of the resonator is completely encapsulated to ensure airtightness; A plastic package body, wherein a thermistor and a control chip are encapsulated in the plastic package body, a first connecting column electrically interconnected is electroplated on the top surface of a portion of the conductive block, and a film block A is adhered to the top surface of another portion of the conductive block, the thermistor, the first connecting column and the top surface of the film block A are coplanar, a circuit is electroplated and connected between the thermistor and the first connecting column, and a film block B with the same height as the circuit is further adhered to the top surface of the film block A, the thermistor is electrically connected to the conductive block through the circuit electroplated inside the plastic package body, thereby achieving electrical connection with the resonator; The top surface of the circuit is plated with a second connecting column, and a film block C is adhered to the top surface of the film block B. The top surfaces of the control chip, the second connecting column and the film block C are coplanar. The film blocks A, B and C are etched and removed to form an electroplating tank. A column is formed by electroplating in the electroplating tank, and the column is electrically connected to the control chip by electroplating. The interconnection layer electrically connects the second connecting column and the control chip, thereby realizing the circuit electrical connection between the control chip and the thermistor. On the one hand, the control chip is directly electrically connected to the conductive block of the resonator through the electroplated column, and on the other hand, it is electrically connected to the circuit of the thermistor through the interconnection layer. On the other hand, the lead-out terminal is electroplated, and an electrically connected rewiring layer is electroplated on the lead-out terminal to adjust the layout of the lead-out terminal, and at the same time, increase the distance from the control chip to the top surface of the plastic package body; The plastic package body and the ceramic resonator form a heterogeneous stacked crystal oscillator. The resonator, thermistor and control chip are stacked in sequence with plastic package materials in between and are electrically connected. The control chip controls the resonator and thermistor to form a temperature-compensated semiconductor packaging structure.

6. The semiconductor package structure according to claim 5, characterized in that: The resonator comprises a base, a crystal plate is arranged in a cavity in the middle of the base, the crystal plate is electrically connected to the electrode pad at the bottom of the resonator through a line in the base wall, a metal cover is covered on the top of the base, and the metal cover and the base body are welded together through a seam sealing.

7. The semiconductor package structure according to claim 5, characterized in that: An external soldering foot electrically connected to the redistribution layer is electroplated on one surface of the plastic package body.

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