CN110856371A

CN110856371A - COB board packaging method for testing and COB board

Info

Publication number: CN110856371A
Application number: CN201910982882.9A
Authority: CN
Inventors: 何桂港; 郑朝晖; 邵疆; 李晓龙; 刘兴辉; 包万双
Original assignee: Shanghai Ji Feng Electronic Ltd By Share Ltd
Current assignee: Shanghai Ji Feng Electronic Ltd By Share Ltd
Priority date: 2019-10-16
Filing date: 2019-10-16
Publication date: 2020-02-28

Abstract

The application provides a COB board packaging method for testing, which comprises the following steps: arranging pin through holes on the PCB, wherein the pin through holes are communicated with the front side and the back side of the PCB; customizing a steel mesh according to the position of the pin arrangement through hole, and printing the soldering paste on the pin arrangement through hole of the PCB in a 45-degree angle by using a scraper; sequentially inserting the test pin header into the pin header through hole of the PCB; placing the PCB board inserted with the test pin header into a reflow soldering furnace, and sequentially carrying out four stages of preheating, soaking, reflowing and cooling. The application also provides a COB board for testing. The COB board encapsulation needs manual welding to arrange the needle and the consuming time that causes, rosin joint and row needle out of plumb scheduling problem among the prior art has been solved to this application board, has greatly shortened the preparation time of the COB board of test usefulness simultaneously, has practiced thrift the human cost, has realized welded high efficiency, high density and high reliability.

Description

COB board packaging method for testing and COB board

Technical Field

The invention relates to the technical field of electronic products, in particular to a packaging method of a COB board for testing and the COB board.

Background

At present, the conventional COB test is to purchase the pin header before testing, and the pin header is welded behind the PCB board for testing through manual work.

The traditional COB packaging process is as follows: 1. horizontally placing a PCB to a workbench; 2. placing a pin header at the through hole of the PCB; 3. heating and melting the tin wire by using an electric iron; 4. manually spot-welding the row of needles; 5. and repeating the steps from 2 to 4, and welding the rest pin rows.

When pin bank quantity is many and intensive, the manual welding degree of difficulty is great, has that the welding is consuming time, rosin joint and pin bank not perpendicular scheduling problem, causes short circuit or open circuit phenomenon, the user test of being not convenient for.

Disclosure of Invention

In view of the above-mentioned not enough of present COB board existence, this application provides COB board's packaging method and COB board of test usefulness to COB board encapsulation needs manual welding pin gang and the consuming time that causes among the solution prior art, rosin joint and pin gang out of plumb scheduling problem.

In order to achieve the purpose, the invention adopts the following technical scheme:

the application provides, in a first aspect, a method for packaging a COB board for testing, including:

the PCB is provided with pin header through holes which are communicated with the front side and the back side of the PCB;

customizing a steel mesh according to the pin arrangement through holes of the PCB, and printing the soldering paste on the pin arrangement through holes of the PCB in a 45-degree angle by using a scraper;

inserting the test pin header into the pin header through hole of the PCB in sequence;

placing the PCB inserted with the test pin header into a reflow soldering furnace, and sequentially carrying out four stages of preheating, soaking, reflowing and cooling; wherein the content of the first and second substances,

a preheating stage: slowly raising the temperature of the reflow oven to a specified soaking or heat preservation temperature;

and (3) soaking: soaking for 60-120 seconds to enable the test pin header and the PCB to reach preset temperatures;

and (3) a reflux stage: heating the PCB to a reflow soldering temperature, keeping the temperature of the PCB constant, and melting solder paste attached to the PCB to perform reflow soldering;

and (3) a cooling stage: the PCB board is cooled to solidify the solder paste.

Preferably, the slow ramp-up slope of the pre-heating phase is 2 ℃/sec.

Preferably, the soaking stage heats the temperature to a preset temperature of 150-183 ℃.

Preferably, the temperature of the refluxing stage is kept between 183 ℃ and 230 ℃, and the duration of the refluxing stage is 30-60 seconds.

Preferably, the temperature drop slope of the cooling phase is 3 ℃/s

In a preferred embodiment, the packaging method further comprises, after the cooling stage:

and (5) checking after the furnace, and detecting whether the packaged PCB meets the quality requirement by using an automatic optical detection device.

More preferably, the packaging method further comprises, after the post-furnace inspection: and reworking the PCB detected to have faults.

In a preferred embodiment, the packaging method further includes, before placing the PCB board in a reflow oven:

and (5) performing furnace inspection, and detecting whether the PCB meets the quality requirement by using an amplification detection device.

More preferably, after the furnace front inspection, the packaging method further comprises: and reworking the PCB detected to have faults.

In a preferred embodiment, the packaging method requires that before the solder paste is printed, the PCB is cleaned by using a cleaning device to remove impurities and dust on the PCB.

In a preferred embodiment, in the packaging method, the solder paste is printed on the PCB board by a solder paste printer at the position where the test pin header needs to be installed.

In a preferred embodiment, the test pin header includes a first section, a second section and a third section which are fixedly connected in sequence, the diameter of the first section is smaller than that of the pin header through hole, the diameter of the second section is larger than that of the pin header through hole, in the packaging method, the test pin header is sequentially inserted into the pin header through hole of the PCB, and the method includes:

inserting the first section into the pin header through hole from the back side of the PCB, wherein one end of the first section, which is far away from the second section, extends out of the front side of the PCB;

and attaching the end face of the second section facing the first section to the back face of the PCB to ensure that the parts of the test pins inserted into the PCB have uniform depth.

The application provides a COB board in the second aspect. Preferably, the COB board is manufactured by the method according to the first aspect of the present application.

In a preferred embodiment, the COB board includes:

the PCB is provided with a region for placing the test chip in the center, and pin header through holes penetrating through the PCB are arranged at intervals at set distances around the region for placing the test chip;

the test pin header is welded and fixed to the pin header through hole, and one surface of the PCB, to which the test chip is attached, is provided with metal wires for correspondingly connecting the test pin header with pins of the test chip;

the test pin header includes:

the first section is inserted into the pin header through hole, and one end of the first section, which is far away from the second section, extends out of the front surface of the PCB; the diameter of the second section is larger than that of the pin header through hole, and the end face of the second section, facing the first section, is attached to the back face of the PCB.

Preferably, the first section, the second section and the third section of the test pin header have the same axial center.

Preferably, the front surface of the PCB board is marked with the number of the test pin header corresponding to the pin header through hole.

Preferably, the distance between every two adjacent test pins along the transverse direction or the longitudinal direction of the PCB board is 2.54 mm.

Preferably, the test pin header meets Socket requirements.

Preferably, the test pins are arranged in a concentric rectangular square array along the periphery of the test chip to the edge of the PCB, and 2-5 circles are enclosed.

Preferably, the test pin header has a length x width of 3.85mm x 0.45 mm.

Preferably, the test pin header and the welding surface of the PCB form a cross line groove.

Preferably, the first section of the test pin header is connected with the PCB by SMT automatic patch.

Preferably, the first section, the second section and the third section of the test pin header all adopt cylindrical copper bars with gold-plated surfaces.

Preferably, the diameter of the third section of the test pin header is the same as the diameter of the first section.

Preferably, the length of the third section of the test pin header is greater than the sum of the lengths of the first and second sections.

Preferably, the front side of the PCB is welded with a golden finger for testing the test chip, the golden finger is provided with a connecting end connected with the test chip, and the golden finger is distributed around the test chip.

More preferably, the number of the gold fingers is: 256 pins to 386 pins.

More preferably, the PCB at the connection position of the golden finger and the PCB is provided with scale marks.

Compared with the prior art, the technical scheme of the application has the following beneficial effects:

1) the packaging method of the COB board for testing is provided, the whole packaging process of the COB board with a large number of part pin headers can be realized without manual welding, time and labor are saved, short circuit and open circuit phenomena are not easy to occur, and high welding efficiency, high density and high reliability are realized;

2) the utility model provides a COB board for test, the last test contact pin of COB board is including fixed connection's first section in order, second section and third section, wherein, first section is used for inserting the pin header through-hole of PCB board, the second section is used for spacingly, it is the uniform depth to ensure to get into the test pin header of PCB board, the third section is used for the follow-up socket of inserting of user to test, this COB board has solved among the prior art COB board encapsulation and has needed manual welding pin header and the consuming time that causes, rosin joint and pin header out of plumb scheduling problem, the preparation time of the COB board of test has greatly been shortened simultaneously, the human cost is practiced thrift.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application. In the drawings:

fig. 1 is a flowchart illustrating a COB board for testing according to an exemplary embodiment;

FIG. 2 is a flowchart illustrating the packaging of a COB board for testing according to the second embodiment;

FIG. 3 is a schematic front view of a COB board according to a third embodiment;

fig. 4 is a schematic view of a back structure of the COB board of the third embodiment.

Illustration of the drawings:

1. a chip bonding area; 2. a golden finger; 3. a pin header through hole; 4. testing the pin header; 5. and (7) a PCB board.

Detailed Description

The invention provides a packaging method of a COB board for testing and the COB board, and in order to make the purpose, technical scheme and effect of the invention clearer and clearer, the invention is further described in detail by referring to the attached drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the above-described drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order, it being understood that the data so used may be interchanged under appropriate circumstances. Furthermore, the terms "comprises," "comprising," and any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The first embodiment is as follows:

fig. 1 is a flowchart illustrating a COB board packaging process for testing according to the present embodiment. As shown in fig. 1, a method for packaging a COB board for testing includes:

s01: arranging pin through holes on the PCB, wherein the pin through holes are communicated with the front side and the back side of the PCB;

s02: customizing a steel mesh according to the position of the pin arrangement through hole of the PCB, and printing soldering paste on the pin arrangement through hole of the PCB in a 45-degree angle by using a scraper in a leaking manner to prepare for welding elements;

s03: sequentially inserting the test pins into pin arranging through holes of the PCB;

s04: placing the PCB board inserted with the test pin header into a reflow soldering furnace, and sequentially carrying out four stages of preheating, soaking, reflowing and cooling; wherein the content of the first and second substances,

a preheating stage: slowly heating the reflow oven with a temperature rise slope of 2 ℃/second

And (3) soaking: soaking for 60-120 seconds to enable the test pin header and the PCB to reach 150-183 ℃;

and (3) a reflux stage: heating the PCB to a reflow soldering temperature to keep the temperature of the PCB constant, and melting soldering paste attached to the PCB to perform reflow soldering, wherein the temperature of a reflow stage is kept at 183-230 ℃, and the duration of the reflow stage is 30-60 seconds;

and (3) a cooling stage: the PCB board is cooled to solidify the solder paste, and the temperature drop slope at the cooling stage is 3 c/sec.

In this embodiment, preheat and to rise to appointed soaking or heat preservation temperature with the PCB board from ambient temperature, make the lower melting point solvent in the soldering paste volatilize to reduce the thermal shock to electronic components, prevent that the programming rate is too fast, can effectively avoid appearing the soldering paste in the soldering paste flux composition worsen, form defects such as tin ball, bridging, prevent that electronic components warp because of bearing too big thermal stress simultaneously. The purpose of the soak is to ensure that all components reach the desired temperature before entering the reflow stage, which typically lasts 60 to 120 seconds, the more efficient the heat transfer during the soak stage, the less time it takes. The reflowed soldering paste exists in a liquid state with the temperature higher than the melting point, and during the period, metal particles in the soldering paste are melted, diffused and dissolved to form an intermetallic compound joint under the action of liquid surface tension; the time the solder paste remains above its melting point (the time above the liquidus) is important to ensure that proper "wetting" occurs between the component and the PCB board, typically 30 to 60 seconds, and should not be exceeded to avoid brittle solder joint formation. The cooling can cool down the PCB to perform the next process, but it is important that the cooling time is controlled, the cooling time cannot be too fast or too slow, and the cooling speed is uniform, generally speaking, the temperature drop slope in the cooling stage is 3 ℃/s, and the uniform cooling speed can prevent the solder paste from edge tilting due to the non-uniform cooling speed.

Example two:

fig. 2 is a flowchart illustrating a COB board packaging process for testing according to the present embodiment. As shown in fig. 2, a method for packaging a COB board for test includes:

SS 01: arranging pin through holes on the PCB, wherein the pin through holes are communicated with the front side and the back side of the PCB;

SS 02: customizing a steel mesh according to the position of the pin arrangement through hole of the PCB, and printing soldering paste on the pin arrangement through hole of the PCB in a 45-degree angle by using a scraper in a leaking manner to prepare for welding elements;

SS 03: sequentially inserting the test pins into pin arranging through holes of the PCB;

SS 04: detecting whether the PCB meets the quality requirement by using an amplification detection device, and reworking the PCB detected to have a fault;

SS 05: placing the PCB board inserted with the test pin header into a reflow soldering furnace, and sequentially carrying out four stages of preheating, soaking, reflowing and cooling; wherein the content of the first and second substances,

a preheating stage: the reflow oven is slowly heated up with the temperature rising slope of 2 ℃/s, so that the condition that the reflow oven is not heated too fast is avoided

and (3) a cooling stage: the PCB board is cooled to solidify the solder paste, and the temperature drop slope of the cooling stage is 3C/sec.

SS 06: and detecting whether the packaged PCB meets the quality requirement by using an automatic optical detection device, and reworking the PCB detected to have a fault.

This embodiment adds two steps to the first embodiment, namely, pre-furnace inspection before placing the PCB board into the reflow oven, and post-furnace inspection after the cooling stage. Before reflow soldering is carried out, the PCB is amplified through the amplification detection device, so that the visual inspection capability of a person can be improved, and whether the polarity of an electronic component is reversed or not, whether mounting deviation occurs or not and the like can be clearly observed; after the reflow soldering is completed, the defects of the soldered PCB can be detected through an automatic optical detection device, such as few tin, many tin, no tin short circuit, tin balls, material leakage, reversed polarity of components, offset of mounting and the like, so that maintenance personnel can repair the PCB. By the aid of the amplification inspection device and the optical detection device, reliability and accuracy of detection results can be guaranteed, and inspection efficiency of products is effectively improved.

In a preferred embodiment, the packaging method needs to use a cleaning device to clean the PCB before printing the solder paste, so as to remove impurities and dust on the PCB, thereby preventing the impurities and dust remaining on the PCB from affecting the soldering quality of the test pin header.

In a preferred embodiment, in the packaging method, the solder paste is printed on the PCB board by a solder paste printer at the position where the test pin header needs to be installed. The efficiency of printing can be improved, the precision of printing is improved to the printing of carrying out the soldering paste through the soldering paste printing machine.

Example three:

as shown in fig. 3 to 4, a COB board for test includes: the PCB comprises a PCB (printed circuit board) 5, wherein a chip bonding area 1 for placing a test chip is arranged in the center of the PCB 5, and pin header through holes 3 penetrating through the PCB 5 are arranged at intervals of a set distance (for example, 2.54mm) around the chip bonding area 1; a test pin header 4 is welded and fixed in the pin header through hole 3, and one surface (front surface, as shown in figure 1) of the PCB 5, on which a test chip is stuck, is provided with a metal wire used for connecting the test pin header 4 with the pin of the test chip correspondingly.

In a preferred embodiment, the front surface of the PCB 5 corresponding to the pin header through hole 3 is marked with the number of the test pin header 4 corresponding to the pin header through hole 3. The test pin header 4 meets Socket requirements.

In a preferred embodiment, the test pins 4 are arranged in a concentric rectangular matrix along the periphery of the test chip to the edge of the PCB 5, and form 2-5 circles. The welding surfaces of the test pin header 4 and the PCB 5 form a cross line groove.

In a preferred embodiment, the front side of the PCB board 5 is welded with a gold finger 2 for testing the test chip, the gold finger 2 is provided with a connecting end connected with the test chip, and the gold finger 2 is distributed around the test chip. The number of the gold fingers 2 is as follows: 256 pins to 386 pins.

The test probe 4 in this embodiment is composed of three cylindrical copper rods with gold-plated surfaces, and specifically includes a first section, a second section, and a third section which are fixedly connected in sequence. Wherein the diameter of the third section of the test pin header 4 is the same as that of the first section, and the length of the third section is greater than the sum of the lengths of the first section and the second section.

The test pin header 4 is soldered to the back side of the PCB board 5 (as shown in fig. 4). The first section of the pin header is inserted into the pin header through hole 3 from the back side of the PCB 5 for welding, and the end of the pin header far away from the second section of the pin header extends out of the front side of the PCB 5. The first section of the test pin header 4 is connected with the PCB 5 in an SMT automatic patch mode. The second section of the pin header is used for limiting, the diameter of the second section is larger than that of the pin header through hole 3, and the second section faces the end face of the first section and is attached to the back face of the PCB 5. The limiting action of the second section ensures that the test pins 4 entering the PCB 5 are of uniform depth. The third section of the test pin header 4 has the longest length, and the section is used for a user to insert a socket for testing. In a preferred embodiment, the test pin header 4 has a length x width of 3.85mm x 0.45 mm.

When the COB board is processed, a preset pin header through hole 3 is formed in a PCB 5, and the pin header through hole 3 is communicated with the front and the back of the PCB 5; then printing the soldering paste on the pin arranging through holes 3 of the PCB 5 by a scraper in a 45-degree angle; sequentially inserting pre-designed test pins 4 into pin arranging through holes 3 of a PCB 5; and placing the PCB 5 with the inserted test pin header 4 into a reflow soldering furnace, and completing the soldering of the test pin header 4 through four stages of preheating, soaking, reflowing and cooling.

The application provides a COB board's that test was used encapsulation method and COB board can realize that the whole packaging process of the COB board that the needle quantity is many does not need manual welding partly to test, and labour saving and time saving has solved among the prior art COB board encapsulation and has need manual welding to arrange the needle and consuming time, rosin joint and row needle out of plumb scheduling problem that causes, has greatly shortened the preparation time of the COB board of test simultaneously, has practiced thrift the human cost.

The embodiments of the present invention have been described in detail, but the embodiments are merely examples, and the present invention is not limited to the embodiments described above. Any equivalent modifications and substitutions to those skilled in the art are also within the scope of the present invention. Accordingly, equivalent changes and modifications made without departing from the spirit and scope of the present invention should be covered by the present invention.

Claims

1. A packaging method of a COB board for testing is characterized by comprising the following steps:

the PCB is provided with pin header through holes which are communicated with the front side and the back side of the PCB; customizing a steel mesh according to the pin arrangement through holes of the PCB, and printing the soldering paste on the pin arrangement through holes of the PCB in a 45-degree angle by using a scraper;

and (3) a cooling stage: the PCB board is cooled to solidify the solder paste.

2. The method for packaging COB boards for testing according to claim 1, wherein: and in the preheating stage, the temperature is slowly increased, and the temperature increase slope is 2 ℃/second.

3. The method for packaging COB boards for testing according to claim 1, wherein: in the soaking stage, the temperature is heated to a preset temperature of 150-183 ℃.

4. The method for packaging COB boards for testing according to claim 1, wherein: the temperature of the reflux stage is kept at 183-230 ℃, and the duration of the reflux stage is 30-60 seconds.

5. The method for packaging COB boards for testing according to claim 1, wherein: the temperature ramp-down slope of the cooling phase was 3 deg.c/sec.

6. The method for packaging COB boards for testing according to claim 1, wherein: the packaging method further comprises the following steps after the cooling stage:

inspecting after the furnace, and detecting whether the packaged PCB meets the quality requirement by using an automatic optical detection device; and reworking the PCB detected to have faults.

7. The method of packaging COB boards for testing according to claim 1, wherein the method further comprises, before the PCB board is placed in the reflow oven:

8. The method for packaging COB boards for testing according to claim 1, wherein: before the soldering paste is printed, the PCB needs to be cleaned by using cleaning equipment, and impurities and dust on the PCB are cleaned.

9. The method for packaging COB boards for testing according to claim 1, wherein: the test pin header comprises a first section, a second section and a third section which are fixedly connected in sequence, the diameter of the first section is smaller than that of the pin header through hole, the diameter of the second section is larger than that of the pin header through hole, and in the packaging method, the test pin header is sequentially inserted into the pin header through hole of the PCB and comprises the following steps:

10. A COB board, comprising:

the test pin header includes: