A production method for improving the production efficiency of SOP type packaging products

Abstract

The present invention relates to a production method for improving the production efficiency of SOP type packaging products, comprising the following steps: S1: manufacturing a lead frame, using a lead frame of a large size of 100mm*300mm, and the lead frame units in the lead frame are arranged in an array of 48*16; S2: chip loading, fixing the chip on the lead frame; S3: bonding; S4: plastic encapsulation, using a plastic encapsulation mold to plastic encapsulate the lead frame, the plastic encapsulation mold includes 6 injection molding channels, each of which is provided with 16 main gates, and each main gate is used to inject 4 products on the left and right sides; S5: rib cutting. Since the number of design channels is greatly reduced, the space reserved for the channels on the lead frame is also reduced in width, so that the arrangement density of the lead frame units can be further increased, and the product density per unit area is the highest in the industry at present, which improves the production efficiency of the equipment and improves the material utilization rate of the plastic encapsulation material and the lead frame.

Description

Technical Field

[0001] The present invention relates to the technical field of chip packaging, and in particular to a production method for improving the production efficiency of SOP type packaging products. Background Art

[0002] The existing chip packaging technology mainly includes the following steps: first, a lead frame is made, and a plurality of lead frame units are arrayed on the lead frame. The lead frame unit includes a base island and pins. The pins also include inner pins and outer pins, which are generally completed by a stamping die; then there is a chip loading process, in which the chip is fixed on the base island of the lead frame unit; then there is a bonding process, in which the lead frame is fixed with a bonding fixture, and the chip is electrically connected to the inner pins of the lead frame unit with metal wires; then there is a plastic encapsulation process, in which the lead frame is plastic encapsulated with a plastic encapsulation mold, and the formed plastic encapsulation body wraps and protects the lead frame, chip and metal wires; finally there is a rib cutting process, in which the entire sheet of plastic encapsulated products is punched into individual products using a rib cutting forming mold.

[0003] In order to further improve the production efficiency of packaging, technicians in this field continue to increase the size of the lead frame, so that more lead frame units can be arrayed, and the arrangement density of the lead frame units can be increased as much as possible, so as to occupy market advantages in material cost, production efficiency and labor cost. For example, for the existing SOP8 / 7 products, the maximum size of the lead frame has reached 100mm*300mm, which is almost the limit that the injection mold can bear. The arrangement density of the lead frame unit reaches 15 rows*40 columns, and the number of products arranged in each lead frame reaches 600pcs. The plastic encapsulation mold needs to be provided with at least 10 runners, each runner is provided with 15 main gates, and each main gate is punched with two products on the left and right sides. Since the main gate needs to ensure a certain width, sufficient space needs to be reserved for the corresponding position on the lead frame. The lead frame unit on the lead frame cannot be further increased in density, and the existing arrangement density has almost reached its limit. Various manufacturers have gradually applied it to actual production, and the production efficiency tends to be the same. Only by continuously further improving product quality and production efficiency can we find a breakthrough in the fierce market competition. Summary of the invention

[0004] The object of the present invention is to provide a production method for improving the production efficiency of SOP type packaging products, so that the production efficiency is further improved on the basis of the existing technology.

[0005] The present invention is achieved by: a production method for improving the production efficiency of SOP type packaging products, comprising the following steps:

[0006] S1: manufacturing a lead frame, using a lead frame of a large size of 100 mm*300 mm, the lead frame units in the lead frame are arranged in an array of 48*16, and every 4 columns of lead frame units form a group, with spacing between groups;

[0007] S2: mounting the chip, fixing the chip on the lead frame;

[0008] S3: bonding, fixing the lead frame with a bonding fixture, and electrically connecting the chip to the pins of the lead frame unit with metal wires;

[0009] S4: Plastic encapsulation: The lead frame is encapsulated by a plastic encapsulation mold. The plastic encapsulation mold includes 6 injection molding channels, each of which is provided with 16 main gates. Each main gate is used to inject 4 products on each of the left and right sides.

[0010] S5: Rib cutting: using the rib cutting forming die to punch out the entire page of plastic-sealed products into individual products.

[0011] Wherein, both the upper and lower molds of the plastic encapsulation mold are provided with ejector pins at the positions of the outer pins of the lead frame unit, which are used to support the outer pins of the lead frame unit during demoulding to provide auxiliary demoulding force.

[0012] Wherein, the pressing width of the pressing strip of the plastic packaging mold is 0.13mm.

[0013] Among them, the demoulding angles of the upper mold cavity and the lower mold cavity of the plastic packaging mold are both 17 degrees, and the inner side surfaces of the upper mold cavity and the lower mold cavity are smooth.

[0014] There are two sets of stamping dies for making the lead frame, and they are processed by step-by-step stamping. The first set of stamping dies is used to process odd-numbered lead frame units, and the second set of stamping dies is used to process even-numbered lead frame units.

[0015] Among them, the pins of the lead frame units of the two adjacent upper and lower products in the same column adopt IDF design to form a cross structure.

[0016] Among them, a glue locking circular hole is designed on the inner pin of the lead frame unit, and a "V" groove structure is designed on the upper and lower surfaces of the inner pin near the edge of the plastic package body. A "U"-shaped groove structure is designed around the base island of the lead frame unit, all of which are used to increase the bonding strength with the plastic package material.

[0017] Among them, in step S5, the rib cutting and forming mold adopts a staggered feeding scheme, and a pre-positioning station is designed on the rib cutting and forming mold. The processing actions of the staggered feeding scheme are: the first step is to cut the connecting rods of the 1st and 3rd columns; the second step is to cut the connecting rods of the 2nd and 4th columns; the third step is to cut the connecting rods of the 5th and 7th columns, pre-form the 2nd and 4th columns, and form the pins of the 1st and 3rd columns; the fourth step is to cut the connecting rods of the 6th and 8th columns, pre-form the 5th and 7th columns, form the pins of the 2nd and 4th columns, and cut off the pins of the 1st and 3rd columns; the fifth step is to cut the connecting rods of the 9th and 11th columns, pre-form the 6th and 8th columns, form the pins of the 5th and 7th columns, cut off the pins of the 2nd and 4th columns, and separate the 1st and 3rd columns, and follow this order until all 16 columns of products are separated.

[0018] Wherein, in step S3, inclined surfaces are provided around the upper end of the boss on the heating block of the bonding fixture.

[0019] Wherein, the SOP type packaging product is a SOP8 or SOP7 type packaging product.

[0020] The beneficial effects of the present invention are as follows: the production method for improving the production efficiency of SOP type packaging products still uses a lead frame of a large size of 100mm*300mm, but the arrangement density of the lead frame unit is higher (the size of the lead frame unit itself has not been changed), and a 48*16 array arrangement is adopted, and every 4 columns of lead frame units form a group, and there is a spacing between the groups (the spacing is mainly used for the space reserved for the layout of the plastic encapsulation mold flow channel), and 768PCS products can be molded at one time, compared with the original 600PCS, the production efficiency is increased by 28%; The plastic encapsulation mold includes 6 injection runners, each of which is equipped with 16 main gates. Each main gate is used to inject 4 products on each side, which greatly reduces the number of runner designs. The space reserved for the runners on the lead frame is also reduced in width, which can further increase the layout density of the lead frame unit. The product density per unit area is the highest in the industry, which improves the production efficiency of the equipment, while improving the material utilization rate of the plastic encapsulation compound and the lead frame, and reducing the material cost. Since the packaging cost of a single product is reduced, the competitiveness of the company's products is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a top view of the SOP8 type package product to be produced by the production method of the present invention;

[0022] Figure 2 It is a side view of a SOP8 type package product to be produced by the production method of the present invention;

[0023] Figure 3 is a schematic structural diagram of a lead frame in the production method of the present invention;

[0024] Figure 4is a schematic diagram of the structure of the first 8 columns of the lead frame in the production method of the present invention;

[0025] Figure 5 It is a structural schematic diagram of a lead frame unit in the production method of the present invention;

[0026] Figure 6 yes Figure 5 Middle AA section view;

[0027] Figure 7 It is a schematic diagram of the matching relationship between the pressing strip of the plastic encapsulation mold and the lead frame in the production method of the present invention;

[0028] Figure 8 It is a cross-sectional schematic diagram of a feeding bottom rail for loading films in the production method of the present invention;

[0029] Fig. 9 It is a schematic diagram of the matching relationship between the upper pressing plate of the bonding fixture and the lead frame in the production method of the present invention;

[0030] Fig.10 is a half-section schematic diagram of an upper pressing plate of a bonding fixture in the production method of the present invention;

[0031] Fig.11 is a top view of a heating block of a bonding fixture in the production method of the present invention;

[0032] Fig.12 It is a schematic diagram of the matching relationship between the boss on the heating block of the bonding fixture and the lead frame in the production method of the present invention;

[0033] Fig.13 It is a schematic diagram of the local matching relationship between the ejector pin distribution of the plastic encapsulation mold and the lead frame in the production method of the present invention;

[0034] Fig.14 It is a partial schematic diagram of the flow channel structure of the plastic sealing mold in the production method of the present invention.

[0035] 1. Product; 11. Plastic package; 12. Pin; 2. Lead frame; 21. Lead frame unit; 211. Base island; 212. Inner pin; 213. Glue locking hole; 214. "V" groove; 215. "U" shaped groove; 3. Injection runner; 31. Main gate; 32. Ejector pin; 4. Press-fitting strip; 5. Feeding bottom rail; 51. Groove; 52. Chamfer; 6. Upper pressure plate; 61. Connecting rib; 7. Heating block; 71. Upper boss; 72. Inclined surface. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] As an embodiment of the production method for improving the production efficiency of SOP type packaging products according to the present invention, Figures 1 to 14 As shown, the following steps are included:

[0038] S1: manufacturing a lead frame 2, using a lead frame 2 of a large size of 100 mm*300 mm, the lead frame units 21 in the lead frame 2 are arranged in an array of 48*16, and every 4 columns of lead frame units 21 form a group, with spacing between groups;

[0039] S2: mounting the chip, fixing the chip on the lead frame;

[0040] S3: Bonding, fixing the lead frame with a bonding fixture, and electrically connecting the chip to the pins of the lead frame unit 21 with metal wires;

[0041] S4: Plastic encapsulation: the lead frame is plastic encapsulated by a plastic encapsulation mold, the plastic encapsulation mold includes 6 injection molding channels 3, each of which is provided with 16 main gates 31, and each main gate 31 is used for injecting 4 products 1 on the left and right sides;

[0042] S5: Rib cutting: using the rib cutting forming die to punch out the entire page of plastic-sealed products into individual products.

[0043] In the present invention, the SOP type packaging product may be a SOP8 or SOP7 type packaging product.

[0044] The production method for improving the production efficiency of SOP type packaging products still uses a lead frame 2 with a large size of 100mm*300mm, but the arrangement density of the lead frame unit 21 is higher (the size of the lead frame unit itself has not been changed), and a 48*16 array arrangement is adopted, and every 4 columns of lead frame units 21 form a group, and there is a spacing between the groups (the spacing is mainly used for the space reserved for the layout of the plastic encapsulation mold flow channel). 768PCS products can be molded at one time, and the production efficiency is increased by 28% compared with the original 600PCS; the plastic encapsulation mold includes 6 There are injection molding channels 3, each of which is provided with 16 main gates 31, and each main gate 31 is used to inject 4 products 1 on the left and right sides, which greatly reduces the number of designed channels. The space reserved for the channel on the lead frame 2 is also reduced in width, so that the layout density of the lead frame unit 21 can be further increased. The product density per unit area is the highest in the industry, which improves the production efficiency of the equipment, while improving the material utilization rate of the plastic packaging material and the lead frame, and reducing the material cost. Since the packaging cost of a single product is reduced, the competitiveness of the company's products is improved.

[0045] In this embodiment, if Fig.13 As shown, both the upper and lower molds of the plastic encapsulation mold are provided with ejector pins 32 at the positions of the outer pins of the lead frame unit, which are used to support the outer pins of the lead frame unit 21 during demoulding to provide auxiliary demoulding force.

[0046] In this embodiment, if Figure 7 As shown, the pressing width of the pressing strip 4 of the plastic encapsulation mold is 0.13mm. In the prior art, the pressing width of the pressing strip of the plastic encapsulation mold is 0.2mm. The present invention breaks the convention and adjusts the pressing width of the pressing strip 4 to 0.13mm to reduce the pressure requirements of the product and the lead frame on the plastic encapsulation system, so that the equipment can play the maximum performance without affecting the service life, and the production efficiency of the equipment is improved by about 30%.

[0047] In this embodiment, the demoulding angles of the upper and lower mold cavities of the plastic encapsulation mold are both 17 degrees, and the inner side surfaces of the upper and lower mold cavities are smooth, which can improve the separation of the product from the upper and lower mold cavities during injection molding, avoid product cracking and delamination, and improve product reliability.

[0048] In this embodiment, there are two sets of stamping dies for making the lead frame, and the stamping process is performed in a step-by-step manner. The first set of stamping dies is used to process odd-numbered lead frame units (1, 3, 5, 7...rows), and the second set of stamping dies is used to process even-numbered lead frame units (2, 4, 6, 8...rows). This method is used to solve the problems of high product density, difficult arrangement of mold tools, and deformation of the lead frame during processing. The material utilization rate of the lead frame is increased by about 28% compared to the current lead frame with a maximum of 15 rows.

[0049] In this embodiment, the pins of the lead frame units of the two adjacent upper and lower products in the same row of products adopt an IDF design to form a cross structure. This can increase the strength of the lead frame to a certain extent, so that it will not deform due to being too soft; at the same time, more lead frame units can be arranged, and 16 rows x 48 columns can be set, thereby improving the material utilization rate of the lead frame.

[0050] In this embodiment, if Figure 5 and Figure 6 As shown, the inner pin 212 of the lead frame unit 21 is designed with a glue locking circular hole 213, which can reduce the stamping and punching force of the stamping tool on the outer pin during the molding of the lead frame during processing, and is also beneficial to increase the bonding strength with the plastic packaging material. The upper and lower surfaces of the inner pin 212 are designed with a "V" groove structure 214 near the edge of the plastic packaging body to increase the bonding strength with the plastic packaging material and prevent delamination caused by punching and pulling; the base island 211 of the lead frame unit is designed with a "U"-shaped groove structure 215 around it to increase the bonding strength between the base island and the plastic packaging material and improve the reliability of the product.

[0051] In this embodiment, in step S5, the rib cutting and forming mold adopts a staggered feeding scheme, and a pre-positioning station is designed on the rib cutting and forming mold. The processing actions of the staggered feeding scheme are: the first step is to cut the connecting rods of the 1st and 3rd columns; the second step is to cut the connecting rods of the 2nd and 4th columns; the third step is to cut the connecting rods of the 5th and 7th columns, pre-form the 2nd and 4th columns, and form the pins of the 1st and 3rd columns; the fourth step is to cut the connecting rods of the 6th and 8th columns, pre-form the 5th and 7th columns, form the pins of the 2nd and 4th columns, and cut off the pins of the 1st and 3rd columns; the fifth step is to cut the connecting rods of the 9th and 11th columns, pre-form the 6th and 8th columns, form the pins of the 5th and 7th columns, cut off the pins of the 2nd and 4th columns, and separate the 1st and 3rd columns, and follow this order until all 16 columns of products are separated. By adopting the step-by-step feeding solution and designing pre-positioning stations on the rib cutting and forming mold, the problems of stepping and rib cutting and forming mold design caused by high product density were effectively solved. At the same time, the equipment efficiency was improved by 113% and the labor cost was saved by about 50%.

[0052] In this embodiment, in step S3, Fig. 9 and Fig.10 As shown, a connecting rib 61 is added to the upper pressing plate 6 of the bonding fixture, and the connecting rib 61 is used to press the four sides of each lead frame unit 21 and expose the middle part of each lead frame unit 21 to be welded (in the prior art, the upper pressing plate only presses the four sides of the part to be worked on the lead frame, and no connecting rib is set in the middle). The connecting rib 61 cooperates with the periphery of the upper pressing plate 6 to press the four sides of each lead frame unit 21, and the width of the connecting rib should be increased as much as possible to prevent and reduce poor pressing. Fig.11 and Fig.12As shown, the upper end of the upper boss 71 of the heating block 7 of the bonding fixture is provided with inclined surfaces 72 around it, and the height of the upper boss is appropriately increased, which can reduce and prevent poor pressing.

[0053] In this embodiment, in step S2, during the chip loading process, a chamfer design is added to the upper edge of the feeding bottom rail groove for loading the chips to prevent the lead frame from being deformed during transportation.

[0054] The above-mentioned embodiment has made corresponding improvements from the lead frame design, the chip mounting process, the bonding process, the plastic packaging process to the rib cutting process. Through the innovative design in these five aspects, the design scheme is extremely innovative, breaking through the bottleneck of the existing technology, and providing solutions for the expected risks, ensuring the stable mass production of the lead frame, and the stable mass production of SOP8 / 7 packaging using the lead frame.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A production method for improving the production efficiency of SOP type packaging products, characterized in that: The following steps are involved: S1: manufacturing a lead frame, using a lead frame of a large size of 100 mm*300 mm, the lead frame units in the lead frame are arranged in an array of 48*16, and every 4 columns of lead frame units form a group, with spacing between groups; S2: mounting the chip, fixing the chip on the lead frame; S3: bonding, fixing the lead frame with a bonding fixture, and electrically connecting the chip to the pins of the lead frame unit with metal wires; S4: Plastic encapsulation: The lead frame is encapsulated by a plastic encapsulation mold. The plastic encapsulation mold includes 6 injection molding channels, each of which is provided with 16 main gates. Each main gate is used to inject 4 products on each of the left and right sides. S5: Rib cutting: using the rib cutting forming die to punch out the entire plastic-sealed product into individual products; In step S5, the rib cutting and forming mold adopts a staggered feeding scheme, and a pre-positioning station is designed on the rib cutting and forming mold. The processing actions of the staggered feeding scheme are: the first step is to cut the connecting rods of the 1st and 3rd columns; the second step is to cut the connecting rods of the 2nd and 4th columns; the third step is to cut the connecting rods of the 5th and 7th columns, pre-form the 2nd and 4th columns, and form the pins of the 1st and 3rd columns; the fourth step is to cut the connecting rods of the 6th and 8th columns, pre-form the 5th and 7th columns, form the pins of the 2nd and 4th columns, and cut off the pins of the 1st and 3rd columns; the fifth step is to cut the connecting rods of the 9th and 11th columns, pre-form the 6th and 8th columns, form the pins of the 5th and 7th columns, cut off the pins of the 2nd and 4th columns, and separate the 1st and 3rd columns, and follow this order until all 16 columns of products are separated.

2. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that, The upper and lower molds of the plastic encapsulation mold are both provided with ejector pins at the positions of the outer pins of the lead frame unit, which are used to support the outer pins of the lead frame unit during demoulding to provide auxiliary demoulding force.

3. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that, The pressing width of the pressing strip of the plastic packaging mold is 0.13mm.

4. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that: The demoulding angles of the upper mold cavity and the lower mold cavity of the plastic packaging mold are both 17 degrees, and the inner side surfaces of the upper mold cavity and the lower mold cavity are smooth.

5. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that: There are two sets of stamping dies for making the lead frame, and the stamping process is performed in a step-by-step manner. The first set of stamping dies is used for processing odd-numbered lead frame units, and the second set of stamping dies is used for processing even-numbered lead frame units.

6. The production method for improving the production efficiency of SOP type packaging products according to claim 5, characterized in that: The pins of the lead frame units of the two adjacent products in the same row are designed with IDF to form a cross structure.

7. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that: The inner pins of the lead frame unit are designed with glue locking circular holes, and the upper and lower surfaces of the inner pins are designed with "V" groove structures near the edge of the plastic package body. The base island of the lead frame unit is designed with "U" shaped groove structures around it, all of which are used to increase the bonding strength with the plastic package material.

8. The production method for improving the production efficiency of SOP type packaging products according to claim 1, characterized in that: In step S3, inclined surfaces are provided around the upper end of the boss on the heating block of the bonding fixture.

9. The production method for improving the production efficiency of SOP type packaging products according to any one of claims 1 to 8, characterized in that: The SOP type packaging product is a SOP8 or SOP7 type packaging product.

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