SOT packaging structure and unpackaging method thereof

Abstract

The invention discloses an SOT packaging structure and an unsealing method thereof, and the method comprises the following steps: 1), carrying out the etching of a plastic package body of a region, which needs to be unsealed, of the SOT packaging structure, and forming a plurality of pits; (2) a watch glass is used for containing chemical acid liquor for unsealing, and the watch glass is placed on a heating table; (3) the product obtained in the step (1) is placed in a watch glass, chemical acid liquor does not immerse the product and only makes contact with the lower surface of the product, and the chemical acid liquor is absorbed through the capillary action of the pits in the chemical acid liquor to corrode and unseal the area needing to be unsealed; (4) after the corrosion is completed, cleaning residues of the corroded plastic package body by using a cleaning agent; and (5) observing the unsealing effect under a microscope, and if the unsealing effect does not meet the requirement, repeating the steps (3) to (5). According to the method, chip surface unsealing can be effectively and rapidly carried out on small SOT products, the unsealing quality is good, the overall operation process is simple, universality is good, and the method is suitable for SOT packaging products of different sizes.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a SOT packaging structure and an unsealing method thereof. Background Art

[0002] SOT (Small Outline Transistor) package is a surface mount package for low-power devices. This package is usually used for SMD low-power transistors. It has a rectangular or square plastic package body with pins extending from both sides or one side. It is a common packaging mode for consumer products. However, due to the small size of the product, it is usually difficult to open the package at a fixed point during the failure analysis process. In addition, since the acid is dripped on the cover of the product, the acid will corrode the overall plastic package structure, which can easily cause the product to fall apart during the analysis process and cannot be further analyzed. Summary of the invention

[0003] In order to solve the technical problems existing in the prior art, the object of the present invention is to provide a SOT packaging structure and an unpacking method thereof.

[0004] In order to achieve the above purpose and the above technical effect, the technical solution adopted by the present invention is:

[0005] A SOT packaging structure comprises a chip, a carrier and a plastic package body, wherein the chip is arranged on the carrier and is plastic-packaged by the plastic package body, the chip is connected to the carrier via welding wires, a plurality of pits are etched on the chip, and a plurality of pins are led out of the chip.

[0006] Furthermore, the pit is located in the area of ​​the chip that needs to be unsealed, and is obtained by laser etching the plastic package body in the area of ​​the chip that needs to be unsealed. The size of the pit is slightly larger than the size of the chip.

[0007] The present invention also discloses a method for unsealing a SOT packaging structure, comprising the following steps:

[0008] 1) Etching the plastic package body in the area to be unsealed of the SOT package structure to form a number of pits;

[0009] 2) Use a watch glass to hold the chemical acid solution for opening the package and place it on the heating table;

[0010] 3) placing the product obtained in step 1) in a watch glass, the chemical acid solution does not immerse the product but only contacts the lower surface of the product, and utilizes the capillary action of the pits in the chemical acid solution to absorb the chemical acid solution to corrode and unseal the area to be unsealed;

[0011] 4) After the corrosion is completed, use a cleaning agent to clean the plastic seal residue after corrosion;

[0012] 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

[0013] Furthermore, in step 1, a laser desealing machine is used to etch the plastic package in the area to be desealed on the chip to form a pit.

[0014] Furthermore, in step 2), the temperature of the heating stage is 110-130°C.

[0015] Furthermore, in step 2), the chemical acid solution is fuming nitric acid or a mixture of concentrated sulfuric acid and fuming nitric acid.

[0016] Furthermore, in step 2), the mass ratio of concentrated sulfuric acid to fuming nitric acid is 2:1 or 3:2.

[0017] Furthermore, in step 3), the corrosion unsealing time is 3 to 5 seconds.

[0018] Furthermore, in step 4), the cleaning agent is acetone.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The invention discloses a SOT packaging structure and an unsealing method thereof, which can effectively and quickly unseal the chip surface of a SOT small-particle product, with intact unsealing quality, a simple overall operation process, good versatility, and is applicable to SOT packaging products of different sizes, thereby solving the problems in the prior art of being unable to normally uncap the chip surface of a SOT packaging product by conventional means, corroding plastic sealing materials at other positions during the uncapping process, easily causing the product structure to fall apart, and affecting result analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the SOT packaging structure of the present invention;

[0022] Figure 2 It is a schematic diagram of placing the SOT packaging structure of the present invention in a watch glass. DETAILED DESCRIPTION

[0023] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0024] A brief summary of one or more aspects is given below to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its only purpose is to give some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be given later.

[0025] like Figure 1 As shown, the present invention discloses a SOT packaging structure, including: a chip 1, a carrier 2 and a plastic package 3, wherein the chip 1 is arranged on the carrier 2 and is plastic-sealed by the plastic package 3, the chip 1 is connected to the carrier 2 through a welding wire 5, and the chip 1 leads to a plurality of pins 6. A laser unsealing machine is used on the chip 1 to etch the plastic package in the area to be unsealed, and a plurality of pits 4 are formed in the area to be unsealed, and the size of the pits is the size of the position where the chip needs to be unsealed. Generally, only the surface of the chip is unsealed, and the size of the pits is slightly larger than the size of the chip.

[0026] The present invention also discloses a method for unsealing a SOT packaging structure, comprising the following steps:

[0027] 1) For the SOT packaging structure, a laser desealing machine is first used to etch the plastic package body in the area to be desealed on the chip 1 to form a plurality of pits 4;

[0028] 2) Use a watch glass 7 to hold an appropriate amount of chemical acid solution 8 for opening, and place it on a heating table at 120° C. In this step, the type of chemical acid solution is selected according to the wire material. If it is a gold wire or silver wire product, fuming nitric acid is used for opening, and if it is a copper wire product, concentrated sulfuric acid + fuming nitric acid is used for opening, and the mass ratio of concentrated sulfuric acid to fuming nitric acid is 2:1 or 3:2;

[0029] 3) Place the product obtained in step 1) in the chemical acid solution in the watch glass 7. The chemical acid solution does not directly immerse the product, but only contacts the lower surface of the product. Figure 2 As shown;

[0030] The pits etched by the laser desealing machine are used to absorb the chemical acid 8 by capillary action in the chemical acid 8 to corrode and deseal the area to be laser desealed, and the processing time is 3 to 5 seconds;

[0031] 4) After the corrosion is completed, the remaining plastic package is cleaned in acetone;

[0032] 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

[0033] Example 1

[0034] like Figure 1-2 As shown, a SOT packaging structure includes: a chip 1, a carrier 2 and a plastic package 3. The chip 1 is arranged on the carrier 2 and is plastic-sealed by the plastic package 3. The chip 1 is connected to the carrier 2 through a welding wire 5. The chip 1 leads to a plurality of pins 6. A laser desealing machine is used on the chip 1 to etch the plastic package in the area to be desealed, and a plurality of pits 4 are formed in the area to be desealed. The size of the pits is slightly larger than the chip size.

[0035] A method for unsealing a SOT package structure, comprising the following steps:

[0036] 1) For the SOT packaging structure, a laser desealing machine is first used to etch the plastic package body in the area to be desealed on the chip 1 to form a plurality of pits 4;

[0037] 2) Select fuming nitric acid as the chemical acid type according to the wire material, use a watch glass 7 to hold an appropriate amount of fuming nitric acid, and place it on a heating table at 120° C.;

[0038] 3) placing the product obtained in step 1) in the chemical acid solution 8 in the watch glass 7, the chemical acid solution 8 does not directly immerse the product, the chemical acid solution 8 only contacts the lower surface of the product, such as Figure 2 As shown;

[0039] The pits etched by the laser desealing machine are used to absorb the chemical acid in the chemical acid solution 8 through capillary action to corrode and deseal the area to be laser desealed. The processing time is 3s.

[0040] 4) After the corrosion is completed, the remaining plastic package is cleaned in acetone;

[0041] 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

[0042] Example 2

[0043] like Figure 1-2 As shown, a SOT packaging structure includes: a chip 1, a carrier 2 and a plastic package 3, wherein the chip 1 is arranged on the carrier 2 and is plastic-sealed by the plastic package 3, the chip 1 is connected to the carrier 2 through a welding wire 5, and the chip 1 leads to a plurality of pins 6. A laser decapsulating machine is used on the chip 1 to etch the plastic package in the area to be decapsulated, and a plurality of pits 4 are formed in the area to be decapsulated, and the size of the pits is slightly larger than the chip size.

[0044] A method for unsealing a SOT package structure, comprising the following steps:

[0045] 1) For the SOT packaging structure, a laser desealing machine is first used to etch the plastic package body in the area to be desealed on the chip 1 to form a plurality of pits 4;

[0046] 2) Select a chemical acid solution of a mixture of concentrated sulfuric acid and fuming nitric acid according to the wire material, the mass ratio of concentrated sulfuric acid to fuming nitric acid is 2:1, use a watch glass 7 to hold an appropriate amount of the mixture of concentrated sulfuric acid and fuming nitric acid, and place it on a heating table at 120° C.;

[0047] 3) The product obtained in step 1) is placed in the chemical acid solution in the watch glass 7. The chemical acid solution 8 does not directly immerse the product, but only contacts the lower surface of the product. Figure 2As shown;

[0048] The pits etched by the laser desealing machine are used to absorb the chemical acid 8 by capillary action in the chemical acid 8 to corrode and deseal the area to be laser desealed, and the processing time is 5s;

[0049] 4) After the corrosion is completed, the remaining plastic package is cleaned in acetone;

[0050] 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

[0051] The rest is the same as in Example 1.

[0052] Example 3

[0053] like Figure 1-2 As shown, a SOT packaging structure includes: a chip 1, a carrier 2 and a plastic package 3, wherein the chip 1 is arranged on the carrier 2 and is plastic-sealed by the plastic package 3, the chip 1 is connected to the carrier 2 through a welding wire 5, and the chip 1 leads to a plurality of pins 6. A laser decapsulating machine is used on the chip 1 to etch the plastic package in the area to be decapsulated, and a plurality of pits 4 are formed in the area to be decapsulated, and the size of the pits is slightly larger than the chip size.

[0054] A method for unsealing a SOT package structure, comprising the following steps:

[0055] 1) For the SOT packaging structure, a laser desealing machine is first used to etch the plastic package body in the area to be desealed on the chip 1 to form a plurality of pits 4;

[0056] 2) Select the type of chemical acid solution as a mixture of concentrated sulfuric acid + fuming nitric acid according to the wire material, the mass ratio of concentrated sulfuric acid to fuming nitric acid is 3:2, use a watch glass 7 to hold an appropriate amount of the mixture of concentrated sulfuric acid + fuming nitric acid, and place it on a heating table at 120° C.;

[0057] 3) placing the product obtained in step 1) in the chemical acid solution 8 in the watch glass 7, the chemical acid solution 8 does not directly immerse the product, the chemical acid solution 8 only contacts the lower surface of the product, such as Figure 2 As shown;

[0058] The pits etched by the laser desealing machine are used to absorb the chemical acid 8 by capillary action in the chemical acid 8 to corrode and deseal the area to be laser desealed, and the processing time is 4s;

[0059] 4) After the corrosion is completed, the remaining plastic package is cleaned in acetone;

[0060] 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

[0061] The rest is the same as in Example 1.

[0062] Parts or structures not specifically described in the present invention may adopt existing technologies or existing products and will not be described in detail here.

[0063] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A SOT packaging structure, characterized in that: The invention comprises a chip, a carrier and a plastic package. The chip is arranged on the carrier and is plastic packaged by the plastic package. The chip is connected to the carrier through welding wires. A plurality of pits are etched on the chip, and a plurality of pins are led out from the chip.

2. A SOT packaging structure according to claim 1, characterized in that: The pit is located in the area of ​​the chip that needs to be unsealed, and is obtained by laser etching the plastic package body in the area of ​​the chip that needs to be unsealed. The size of the pit is slightly larger than the size of the chip.

3. A method for unsealing a SOT package structure according to claim 1 or 2, characterized in that: The following steps are involved: 1) Etching the plastic package body in the area to be unsealed of the SOT package structure to form a number of pits; 2) Use a watch glass to hold the chemical acid solution for opening the package and place it on the heating table; 3) placing the product obtained in step 1) in a watch glass, the chemical acid solution does not immerse the product but only contacts the lower surface of the product, and utilizes the capillary action of the pits in the chemical acid solution to absorb the chemical acid solution to corrode and unseal the area to be unsealed; 4) After the corrosion is completed, use a cleaning agent to clean the plastic seal residue after corrosion; 5) Place the container under a microscope to observe the unsealing effect. If the unsealing effect does not meet the requirements, repeat steps 3) to 5).

4. The method for unsealing a SOT package structure according to claim 3, characterized in that: In step 1, a laser desealing machine is used to etch the plastic package in the area to be desealed on the chip to form a pit.

5. The method for unsealing a SOT package structure according to claim 3, characterized in that: In step 2), the temperature of the heating stage is 110-130°C.

6. The method for unsealing a SOT package structure according to claim 3, characterized in that: In step 2), the chemical acid solution is fuming nitric acid or a mixture of concentrated sulfuric acid and fuming nitric acid.

7. The method for unsealing a SOT package structure according to claim 6, characterized in that: In step 2), the mass ratio of concentrated sulfuric acid to fuming nitric acid is 2:1 or 3:

2.

8. The method for unsealing a SOT package structure according to claim 3, characterized in that: In step 3), the corrosion unsealing time is 3 to 5 seconds.

9. The method for unsealing a SOT package structure according to claim 3, characterized in that: In step 4), the cleaning agent is acetone.

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