Reworking method of plastic package sheet

Abstract

The invention relates to a reworking method of a plastic package sheet, and relates to the technical field of semiconductors, in the reworking method of the plastic package sheet, the plastic package sheet to be reworked comprises a substrate, a chip and a first plastic package layer, and because the first plastic package layer only covers part of the chip, package is damaged. Therefore, the first plastic package layer is thinned to form the first plastic package middle layer, the surface, far away from the substrate, of the first plastic package middle layer is flat, then the first plastic package middle layer between the adjacent chips is removed, the second plastic package middle layer with the groove is formed, and at the moment, due to the fact that most of the damaged first plastic package layer is removed, the first plastic package middle layer is not damaged. The defect of incomplete filling is reduced, and packaging can be better realized when the second plastic packaging layer is formed on the chip, the substrate and the second plastic packaging middle layer. The first plastic package layer is reworked, and the plastic package sheet is subjected to plastic package again, so that the reliability is improved, and meanwhile, the product yield is improved.

Description

Technical Field

[0001] The present application relates to the field of packaging technology, and in particular to a reworking method for a plastic packaging sheet. Background Art

[0002] Packaging technology is a key link in the semiconductor industry chain. When plastic-sealing wafers, the wafers need to be placed in the packaging mold cavity to complete the packaging process.

[0003] During this process, if the wafer encounters insufficient adsorption, it must be removed from the encapsulation mold cavity and re-adsorbed. However, due to the high temperature of the chassis inside the encapsulation mold cavity, the encapsulation material will undergo an irreversible curing reaction when exposed to high temperature. Even if the wafer is readjusted and encapsulated again, the cured encapsulation material will not re-melt and flow. This will result in defects such as incomplete filling in the final encapsulated product, resulting in zero product yield. Summary of the Invention

[0004] Based on this, it is necessary to provide a rework method for plastic packaging sheets to address the problem of zero product yield and improve product yield.

[0005] In order to achieve the above object, the present invention provides a method for reworking a plastic packaging sheet, comprising:

[0006] Providing a plastic packaging sheet to be reworked, the plastic packaging sheet to be reworked comprising a substrate, chips and a first plastic packaging layer, wherein a plurality of the chips are located on one side of the substrate, and the first plastic packaging layer covers a portion of the chips;

[0007] Performing a thinning process on the first plastic encapsulation layer to form a first plastic encapsulation intermediate layer, wherein a surface of the first plastic encapsulation intermediate layer away from the substrate is flat;

[0008] removing the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer having a groove;

[0009] A second plastic packaging layer is formed on the chip, the substrate and the second plastic packaging intermediate layer.

[0010] In one embodiment, the distance between the surface of the first molding intermediate layer away from the substrate and the substrate is H, the distance between the surface of the chip away from the substrate and the substrate is h, and H is greater than h.

[0011] In one embodiment, the second plastic encapsulation intermediate layer covers the surface of the substrate and the sidewalls of the chip.

[0012] In one embodiment, the thinning process of the first plastic encapsulation layer to form a first plastic encapsulation intermediate layer includes:

[0013] The first plastic encapsulation layer is scraped off with a first scraper to form the first plastic encapsulation intermediate layer.

[0014] In one embodiment, scraping the first plastic encapsulation layer with a first scraper to form the first plastic encapsulation intermediate layer includes:

[0015] Determining a cutting position according to a boundary of the first plastic sealing layer;

[0016] Moving the first scraper along a first direction to scrape off the first plastic sealing layer, wherein the first direction is parallel to the substrate;

[0017] moving the first scraper a first distance along a second direction, wherein the second direction is parallel to the substrate and perpendicular to the first direction;

[0018] Return to the step of moving the first scraper along the first direction to scrape the first plastic encapsulation layer until the first plastic encapsulation intermediate layer is formed.

[0019] In one embodiment, the first scraper is a circular cutter; the value of the first distance is half of the width of the circular cutter in the second direction.

[0020] In one embodiment, removing the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer having a groove includes:

[0021] A second scraper is used to remove the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer with a groove. The width of the first scraper in the second direction is greater than the width of the second scraper in the second direction.

[0022] In one embodiment, the second scraper is a hard blade.

[0023] In one embodiment, before thinning the first plastic encapsulation layer to form the first plastic encapsulation intermediate layer, the method includes:

[0024] measuring a maximum value of a third distance between a first surface of the first plastic encapsulation layer and a second surface of the chip in a direction perpendicular to the substrate, where the first surface is a surface of the first plastic encapsulation layer away from the substrate, and the second surface is a surface of the chip away from the substrate;

[0025] When the maximum value of the third interval is less than a preset height value, performing a thinning process on the first plastic encapsulation layer to form the first plastic encapsulation intermediate layer;

[0026] When the maximum value of the third interval is greater than the preset height value, the first plastic encapsulation layer is thinned multiple times to form the first plastic encapsulation intermediate layer.

[0027] In one embodiment, before forming the second plastic encapsulation layer on the chip, the substrate, and the second plastic encapsulation intermediate layer, the method includes:

[0028] Plasma treatment is performed on the chip, the substrate and the second plastic packaging intermediate layer.

[0029] Compared with the existing technology, the above technical solution has the following advantages:

[0030] In this plastic encapsulation sheet rework method, the plastic encapsulation sheet to be reworked includes a substrate, a chip, and a first plastic encapsulation layer. Since the first plastic encapsulation layer only covers a portion of the chip, the encapsulation is damaged. Therefore, the first plastic encapsulation layer is first thinned to form a first plastic encapsulation intermediate layer, the surface of which is away from the substrate and is flat. Then, the first plastic encapsulation intermediate layer between adjacent chips is removed to form a second plastic encapsulation intermediate layer with grooves. At this time, since most of the damaged first plastic encapsulation layer has been removed, the defect of incomplete filling is reduced. When the second plastic encapsulation layer is then formed on the chip, substrate, and second plastic encapsulation intermediate layer, better encapsulation can be achieved. Since the first plastic encapsulation layer is reworked and the plastic encapsulation sheet is re-encapsulated, reliability is improved while the product yield is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 A schematic diagram of a rework process of a plastic packaging sheet is provided for an embodiment of the present application;

[0033] Figure 2 A schematic top view of a plastic packaging sheet to be reworked is provided for an embodiment of the present application;

[0034] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure along the AA' plane;

[0035] Figure 4 A schematic diagram of a cross-sectional structure after forming a first plastic encapsulation intermediate layer is provided for an embodiment of the present application;

[0036] Figure 5A schematic diagram of a cross-sectional structure after forming a second plastic encapsulation intermediate layer is provided for an embodiment of the present application;

[0037] Figure 6 A schematic diagram of the cross-sectional structure after forming a second plastic sealing layer is provided for an embodiment of the present application.

[0038] Description of the accompanying drawings: 11 - substrate; 12 - chip; 13 - first plastic packaging layer; 131 - first plastic packaging middle layer; 132 - second plastic packaging middle layer; 14 - second plastic packaging layer. DETAILED DESCRIPTION

[0039] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0041] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to, or coupled to" another element or layer, it can be directly on, adjacent to, connected to, or coupled to the other element or layer, or there can be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to, or directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion.

[0042] Spatially relative terms such as "under," "beneath," "beneath," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the drawings is turned over, the element or feature described as "under" or "beneath" or "beneath" the other elements will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" can include both upper and lower orientations. In addition, the device can also include alternative orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0043] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Also, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0044] In order to make the purpose, features and advantages of this application more obvious and easy to understand, this application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0045] In one embodiment, please refer to Figure 1 , Figure 1 A schematic diagram of a reworking process of a plastic packaging sheet is provided for an embodiment of the present application. The reworking method of the plastic packaging sheet includes the following steps:

[0046] Step S01: providing a plastic package sheet to be reworked, the plastic package sheet to be reworked includes a substrate 11, a chip 12 and a first plastic package layer 13, a plurality of chips 12 are located on one side of the substrate 11, and the first plastic package layer 13 covers part of the chips 12 (refer to Figure 2 And reference Figure 3 ).

[0047] In this step, the plastic encapsulation sheet to be reworked is one that was damaged due to a previous packaging error. Substrate 11 can be a glass substrate, and multiple chips 12 can be arranged in an array on one side of substrate 11. Because the first plastic encapsulation layer 13 solidifies before the plastic encapsulation adhesive is spread, it only covers a portion of substrate 11 and chips 12. At this point, because the amount of plastic encapsulation adhesive is pre-calculated, the maximum thickness of first plastic encapsulation layer 13 from the surface of substrate 11 in a direction perpendicular to substrate 11 is greater than a predetermined thickness. This results in an irregular raised structure.

[0048] Step S02: Thinning the first plastic encapsulation layer 13 to form a first plastic encapsulation intermediate layer 131. The surface of the first plastic encapsulation intermediate layer 131 away from the substrate 11 is flat (refer to Figure 4 ).

[0049] In this step, the first plastic encapsulation layer 13 on the side of the chip 12 away from the substrate 11 is thinned to remove part of the first plastic encapsulation layer 13, so that the surface of the formed first plastic encapsulation intermediate layer 131 away from the substrate 11 is flat, so as to facilitate the calculation of the glue amount during subsequent repackaging.

[0050] Step S03: removing the first plastic encapsulation intermediate layer 131 between two adjacent chips 12 to form a second plastic encapsulation intermediate layer 132 with a groove (refer to Figure 5 ).

[0051] In this step, in the cutting lanes between the covered chips 12, problems such as bubbles or uneven filling caused by improper packaging will reduce the reliability of subsequent packaging. Therefore, the first plastic encapsulation intermediate layer 131 between two adjacent chips 12 can be removed, and the second plastic encapsulation intermediate layer 132 formed at this time has a groove.

[0052] Step S04: forming a second plastic encapsulation layer 14 on the chip 12, the substrate 11 and the second plastic encapsulation intermediate layer 132 (refer to Figure 6 ).

[0053] In this step, since the damaged first plastic encapsulation layer 13 is thinned and removed, the amount of plastic encapsulation adhesive can be more easily calculated during repackaging. This facilitates repackaging of the chips 12, substrate 11, and second plastic encapsulation intermediate layer 132. The repackaging-formed second plastic encapsulation layer 14 can evenly cover all chips 12, providing higher reliability. At this point, the second plastic encapsulation layer 14 has a first height, which is equal to a predetermined height.

[0054] In this embodiment, the plastic encapsulation sheet to be reworked includes a substrate 11, a chip 12, and a first plastic encapsulation layer 13. Since the first plastic encapsulation layer 13 only covers a portion of the chip 12, the package is damaged. Therefore, the first plastic encapsulation layer 13 is first thinned to form a first plastic encapsulation intermediate layer 131. The surface of the first plastic encapsulation intermediate layer 131 away from the substrate 11 is flat. Then, the first plastic encapsulation intermediate layer 131 between adjacent chips 12 is removed to form a second plastic encapsulation intermediate layer 132 with a groove. At this time, since most of the damaged first plastic encapsulation layer 13 has been removed, the defect of incomplete filling is reduced. Then, when the second plastic encapsulation layer 14 is formed on the chip 12, the substrate 11, and the second plastic encapsulation intermediate layer 132, better packaging can be achieved. Since the first plastic encapsulation layer 13 is reworked and the plastic encapsulation sheet is re-molded, reliability is improved while improving product yield.

[0055] In another embodiment of the present application, the distance between the surface of the first plastic encapsulation intermediate layer 131 away from the substrate 11 and the substrate 11 is H, and the distance between the surface of the chip 12 away from the substrate 11 and the substrate 11 is h, and H is greater than h (refer to Figure 4 ).

[0056] Specifically, when the first plastic encapsulation layer 13 is thinned, in order to protect the chip 12 covered by the first plastic encapsulation layer 13 from being damaged, the thinned first plastic encapsulation intermediate layer 131 is set to cover the chip 12. That is, the distance between the surface of the first plastic encapsulation intermediate layer 131 away from the substrate 11 and the substrate 11 is greater than the distance between the surface of the chip 12 away from the substrate 11 and the substrate 11, that is, H is greater than h.

[0057] It should be noted that the difference of H minus h may range from 50 μm to 100 μm, including endpoint values. For example, the difference of H minus h may range from 50 μm, 70 μm, or 87 μm, etc., and is not specifically limited.

[0058] In this embodiment, the distance between the surface of the first plastic encapsulation intermediate layer 131 away from the substrate 11 and the substrate 11 is set to be greater than the distance between the surface of the chip 12 away from the substrate 11 and the substrate 11, which can protect the chip 12 from damage and improve the reliability of subsequent packaging.

[0059] In another embodiment of the present application, the second plastic encapsulation intermediate layer 132 covers the surface of the substrate 11 and the sidewalls of the chip 12 (refer to Figure 5 ).

[0060] Specifically, the second plastic encapsulation intermediate layer 132 is obtained by removing the first plastic encapsulation intermediate layer 131 between adjacent chips 12. When removing the first plastic encapsulation intermediate layer 131 between adjacent chips 12, in order to protect the side walls of the chip 12 and the substrate 11 from being damaged, part of the first plastic encapsulation intermediate layer 131 on the side walls of the chip 12 and the surface of the substrate 11 can be retained when forming the groove.

[0061] In an embodiment, a second plastic encapsulation intermediate layer 132 is provided to cover the surface of the substrate 11 and the sidewalls of the chip 12 , which can protect the chip 12 and substrate 11 covered by the first plastic encapsulation layer 13 from being damaged, thereby improving the reliability of subsequent packaging.

[0062] In another embodiment of the present application, the first plastic encapsulation layer 13 is thinned to form a first plastic encapsulation intermediate layer 131, including:

[0063] The first plastic encapsulation layer 13 is scraped off with a first scraper to form a first plastic encapsulation intermediate layer 131 .

[0064] Specifically, since some chips 12 on the substrate 11 have not been packaged, the first scraper is used to scrape the first plastic packaging layer 13, which can prevent damage to other chips 12 and improve the reliability of subsequent packaging.

[0065] In another embodiment of the present application, the first plastic encapsulation layer 13 is scraped off with a first scraper to form a first plastic encapsulation intermediate layer 131, including:

[0066] Step S021 : determining a cutting position according to the boundary of the first plastic packaging layer 13 .

[0067] In this step, since the edge of the first plastic sealing layer 13 is irregular, it is necessary to first determine the boundary of the first plastic sealing layer 13 and then determine the blade entry position according to the boundary, which can improve the scraping efficiency.

[0068] Step S022: Move the first scraper along the first direction X to scrape off the first plastic layer 13. The first direction X is parallel to the substrate 11 (refer to Figure 2 ).

[0069] Step S023: Move the first scraper along the second direction Y by a first distance, wherein the second direction Y is parallel to the substrate 11 and perpendicular to the first direction X (reference Figure 2 ).

[0070] Step S024 : returning to the step of moving the first scraper along the first direction X to scrape the first plastic encapsulation layer 13 until the first plastic encapsulation intermediate layer 131 is formed.

[0071] Specifically, when scraping the first plastic encapsulation layer 13, due to the limited width of the first scraper, multiple scraping operations are required to flatten the surface of the first plastic encapsulation layer 13 away from the substrate 11. The first scraper first moves along a first direction X. After completing one scraping operation, the first scraper is lifted in a direction perpendicular to the substrate 11 and then returned to its original position. The scraper is then moved a first distance in a second direction Y perpendicular to the first direction X and then moved again in the first direction X until a flat first plastic encapsulation intermediate layer 131 is formed.

[0072] In this embodiment, the first scraper moves multiple times to scrape off part of the first plastic packaging layer 13 without affecting other chips 12 , thereby further improving the yield rate of the final product.

[0073] In another embodiment of the present application, the first scraper is a circular cutter; the value of the first distance is half of the width of the circular cutter in the second direction Y.

[0074] Specifically, the first scraper may be a circular cutter. It should be noted that the width of the circular cutter in the second direction Y may be 1 mm, and there is no specific limitation on the width of the circular cutter. To avoid incomplete scraping, each time the circular cutter moves in the second direction Y, it may only move half of the width of the circular cutter. That is, when the width of the circular cutter in the second direction Y is 1 mm, the first distance moved by the circular cutter may be 0.5 mm.

[0075] In this embodiment, each time the circular cutting blade moves the first distance in the second direction Y, not only can the problem of blade chipping during scraping be reduced, but also a first plastic encapsulation intermediate layer 131 with better quality can be formed.

[0076] In another embodiment of the present application, the first plastic encapsulation intermediate layer 131 between two adjacent chips 12 is removed to form a second plastic encapsulation intermediate layer 132 having a groove, including:

[0077] A second scraper is used to remove the first molding intermediate layer 131 between two adjacent chips 12 to form a second molding intermediate layer 132 with a groove. The width of the first scraper in the second direction Y is greater than the width of the second scraper in the second direction Y.

[0078] Specifically, the premature curing of the encapsulant during the formation of the first encapsulation layer 13 results in a high number of bubbles and gaps in the encapsulation material between adjacent chips 12, leading to insufficient reliability in the subsequent encapsulation. Therefore, a second scraper is used to remove the first encapsulation intermediate layer 131 between two adjacent chips 12, allowing the encapsulant to flow more easily during subsequent re-encapsulation, thereby improving product reliability. In one embodiment, the groove area is smaller than the area between two adjacent chips 12 to prevent damage to the chips 12.

[0079] It should be noted that the width of the first scraper in the second direction Y is greater than the width of the second scraper in the second direction Y. Since there are more first plastic encapsulation layers 13 on the surface, a first scraper with a larger width is used, and the spacing between the chips 12 is smaller, so a second scraper with a smaller width is used.

[0080] In this step, the first scraper has a wider width in the second direction Y to increase the scraping rate, and the second scraper has a narrower width to better adapt to the spacing between the chips 12, making the scraping more precise.

[0081] In this embodiment, the second scraper can be used to scrape only the first plastic packaging intermediate layer 131 between adjacent chips 12 without damaging other areas, thereby ensuring the reliability of subsequent packaging.

[0082] In another embodiment of the present application, the second scraper is a hard blade.

[0083] Specifically, the second scraper can be a hard blade. Since the spacing between adjacent chips 12 is small, a hard blade with a smaller width in the second direction Y is required for scraping. In this case, if the spacing between chips 12 is 160 μm, the width of the hard blade in the second direction Y can be 50 μm, and multiple scraping operations can be performed.

[0084] For example, a second scraper is used to remove the first plastic encapsulation intermediate layer 131 between two adjacent chips 12 to form a second plastic encapsulation intermediate layer 132 having a groove, including:

[0085] Step S031 : determining a cutting position according to the spacing between adjacent chips 12 .

[0086] In this step, in order not to damage the chip 12, it is necessary to first determine the position of the spacing between adjacent chips 12, and then determine the knife entry position according to the position of the spacing between adjacent chips 12, which can improve the scraping efficiency.

[0087] Step S032 : moving the second scraper along a first direction X to scrape off the first plastic encapsulation intermediate layer 131 , where the first direction X is parallel to the substrate 11 .

[0088] Step S033 : moving the second scraper a second distance along a second direction Y, where the second direction Y is parallel to the substrate 11 and perpendicular to the first direction X.

[0089] Step S034 : returning to the step of moving the second scraper along the first direction X to scrape off the first molding intermediate layer 131 until the second molding intermediate layer 132 is formed.

[0090] When scraping the first plastic encapsulation interlayer 131, due to the limited width of the second scraper, multiple scraping operations are required to evenly remove the first plastic encapsulation interlayer 131 between adjacent chips 12. The second scraper first moves along a first direction X, then retracts and then moves a second distance in a second direction Y perpendicular to the first direction X. The second scraper is then moved again in the first direction X until the second plastic encapsulation interlayer 132 is formed. The multiple scraping operations of the second scraper to remove the first plastic encapsulation interlayer 131 between adjacent chips 12 do not affect other chips 12, further improving the yield rate of the final product.

[0091] It should be noted that the value of the second distance can be half of the width of the hard knife in the second direction Y. Such a setting can reduce the problem of knife chipping during scraping.

[0092] In another embodiment of the present application, before the first plastic encapsulation layer 13 is thinned to form the first plastic encapsulation intermediate layer 131, the following steps are included:

[0093] Step S12: Measure the maximum value of the third distance between the first surface of the first plastic encapsulation layer 13 and the second surface of the chip 12 in a direction perpendicular to the substrate 11, where the first surface is the surface of the first plastic encapsulation layer 13 away from the substrate 11, and the second surface is the surface of the chip 12 away from the substrate 11.

[0094] In this step, if the thickness of the first plastic encapsulation layer 13 is too high, it may not be able to enter the circular cutting mold cavity. Therefore, the maximum value of the third distance between the first surface of the first plastic encapsulation layer 13 and the second surface of the chip 12 in the direction perpendicular to the substrate 11 can be measured to calculate whether the total height of the substrate 11, chip 12, and first plastic encapsulation layer 13 can enter the circular cutting mold cavity. If it cannot enter, some of the first plastic encapsulation layer 13 can be manually ground off without damaging other chips 12 to allow the plastic encapsulation sheet to enter the circular cutting mold cavity.

[0095] Step S22 : when the maximum value of the third interval is smaller than the preset height value, performing a thinning process on the first plastic packaging layer 13 to form a first plastic packaging intermediate layer 131 .

[0096] In this step, since the height of the cutting edge of the circular cutter is fixed in the direction perpendicular to the substrate 11, the height of the cutting edge of the circular cutter is given a higher priority, and the height value of the cutting edge of the circular cutter is used as the preset height value. After measuring the maximum value of the third spacing, the maximum value of the third spacing can be compared with the height value of the cutting edge of the circular cutter. If the maximum value of the third spacing is less than the preset height value, only one thinning process is performed.

[0097] Step S32 : when the maximum value of the third interval is greater than the preset height value, performing multiple thinning processes on the first plastic packaging layer 13 to form a first plastic packaging intermediate layer 131 .

[0098] If the maximum value of the third distance is greater than the preset height, a single scraping operation can still produce a flat surface, but the first plastic encapsulation layer 13 on the surface of the chip 12 away from the substrate 11 will be thicker. Because the previously formed first plastic encapsulation layer 13 is uneven, it is prone to forming voids and bubbles, resulting in low reliability of the final product. Therefore, the first plastic encapsulation layer 13 can be thinned multiple times to ensure a higher yield rate for the subsequent repackaged product.

[0099] In another embodiment of the present application, before forming the second plastic encapsulation layer 14 on the chip 12 , the substrate 11 and the second plastic encapsulation intermediate layer 132 , the following steps are included:

[0100] The chip 12 , the substrate 11 and the second plastic packaging intermediate layer 132 are subjected to plasma treatment.

[0101] Specifically, after forming the second molding intermediate layer 132, the chip 12, substrate 11, and second molding intermediate layer 132 may be subjected to a plasma treatment. The plasma treatment may use an inert gas such as oxygen or argon, which not only cleans the molding sheet but also increases the surface roughness of the second molding intermediate layer 132, thereby improving the bonding strength between the subsequently formed second molding intermediate layer 14 and the second molding intermediate layer 132.

[0102] When forming the second plastic encapsulation layer 14 on the chip 12, the substrate 11 and the second plastic encapsulation intermediate layer 132, the volume of the second plastic encapsulation intermediate layer 132 can be estimated first, and then the required amount of plastic encapsulation glue can be calculated. The calculation formula can be: glue amount in grams = (total volume of the plastic encapsulation sheet - chip volume - volume of the second plastic encapsulation intermediate layer) × density of the plastic encapsulation glue. Then, in the plastic encapsulation mold cavity, the plastic encapsulation glue is evenly spread and cured to form the second plastic encapsulation layer 14.

[0103] In this step, the plasma treatment not only cleans the plastic packaging sheet to prevent pollutants from affecting reliability, but also increases the bonding force between the second plastic packaging layer 14 and the second plastic packaging intermediate layer 132, thereby improving product reliability.

[0104] In the description of this specification, reference to the terms "some embodiments" or "another embodiment" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0105] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features of the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for reworking a plastic sheet, characterized in that: include: Providing a plastic packaging sheet to be reworked, the plastic packaging sheet to be reworked comprising a substrate, chips and a first plastic packaging layer, wherein a plurality of the chips are located on one side of the substrate, and the first plastic packaging layer covers a portion of the chips; Performing a thinning process on the first plastic encapsulation layer to form a first plastic encapsulation intermediate layer, wherein a surface of the first plastic encapsulation intermediate layer away from the substrate is flat; removing the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer having a groove; A second plastic packaging layer is formed on the chip, the substrate and the second plastic packaging intermediate layer.

2. The reworking method of the plastic packaging sheet according to claim 1, characterized in that: The distance between the surface of the first plastic encapsulation intermediate layer away from the substrate and the substrate is H, the distance between the surface of the chip away from the substrate and the substrate is h, and H is greater than h.

3. The reworking method of the plastic packaging sheet according to claim 1, characterized in that: The second plastic packaging intermediate layer covers the surface of the substrate and the sidewalls of the chip.

4. The reworking method of the plastic packaging sheet according to claim 1, characterized in that: The thinning process of the first plastic encapsulation layer to form a first plastic encapsulation intermediate layer includes: The first plastic encapsulation layer is scraped off with a first scraper to form the first plastic encapsulation intermediate layer.

5. The reworking method of the plastic packaging sheet according to claim 4, characterized in that: The step of scraping the first plastic encapsulation layer with a first scraper to form the first plastic encapsulation intermediate layer includes: Determining a cutting position according to a boundary of the first plastic sealing layer; Moving the first scraper along a first direction to scrape off the first plastic sealing layer, wherein the first direction is parallel to the substrate; moving the first scraper a first distance along a second direction, wherein the second direction is parallel to the substrate and perpendicular to the first direction; Return to the step of moving the first scraper along the first direction to scrape the first plastic encapsulation layer until the first plastic encapsulation intermediate layer is formed.

6. The method for reworking a plastic packaging sheet according to claim 5, wherein: The first scraper is a circular cutter; the value of the first distance is half of the width of the circular cutter in the second direction.

7. The method for reworking a plastic packaging sheet according to claim 4, wherein: The step of removing the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer having a groove includes: A second scraper is used to remove the first plastic encapsulation intermediate layer between two adjacent chips to form a second plastic encapsulation intermediate layer with a groove. The width of the first scraper in the second direction is greater than the width of the second scraper in the second direction.

8. The method for reworking a plastic packaging sheet according to claim 7, wherein: The second scraper is a hard blade.

9. The method for reworking a plastic packaging sheet according to claim 1, wherein: Before thinning the first plastic encapsulation layer to form a first plastic encapsulation intermediate layer, the method includes: measuring a maximum value of a third distance between a first surface of the first plastic encapsulation layer and a second surface of the chip in a direction perpendicular to the substrate, where the first surface is a surface of the first plastic encapsulation layer away from the substrate, and the second surface is a surface of the chip away from the substrate; When the maximum value of the third interval is less than a preset height value, performing a thinning process on the first plastic encapsulation layer to form the first plastic encapsulation intermediate layer; When the maximum value of the third interval is greater than the preset height value, the first plastic encapsulation layer is thinned multiple times to form the first plastic encapsulation intermediate layer.

10. The method for reworking a plastic packaging sheet according to claim 1, wherein: Before forming the second plastic encapsulation layer on the chip, the substrate and the second plastic encapsulation intermediate layer, the method includes: Plasma treatment is performed on the chip, the substrate and the second plastic packaging intermediate layer.

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