Semiconductor wafer positive pressure packaging method

Abstract

This invention discloses a positive pressure packaging method for semiconductor wafers, relating to the field of semiconductor packaging technology, comprising the following steps: S1: placing the wafer into an inner bag; S2: ventilating the glove box; S3: placing the inner bag into the glove box and allowing it to stand; S4: sealing with pulse heating to complete the packaging. This invention avoids negative pressure treatment on the inner bag containing the wafer, preventing particle shedding from the wafer surface, wafer deformation under stress, wrinkling and air leakage at the seal, and serious wafer contamination problems caused by Outgas seeping from the carrier and the inner and outer bags of the packaging. This ensures that the wafer is unaffected by the external environment when opened for use. The pulse heating sealing method ensures good fusion quality of the inner bag seal plastic, and the process is simple and achieves a high level of cleanliness.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to a positive pressure packaging method for semiconductor wafers. Background Technology

[0002] Semiconductor wafers, including Si wafers, Ge wafers, GaAs wafers, InP wafers, and GaN wafers, undergo polishing and cleaning to remove all particles, metal ions, and organic contaminants from their surfaces, resulting in excellent roughness, flatness, and cleanliness. As ready-to-use semiconductor substrate materials for subsequent epitaxial growth, they must be packaged and transported to the next-stage customer for storage within a specified shelf life. The semiconductor wafers are first carried in rigid carriers such as round boxes or cassettes, then packaged in clean plastic inner bags (PE / NYLON) and aluminum foil outer bags before being provided to the customer for epitaxial growth and processing into semiconductor devices within a specified timeframe.

[0003] In existing technology, vacuum packaging machines are commonly used for negative pressure packaging of semiconductor wafers. The process involves placing the cleaned, polished wafers into a clean round box or cassette after inspection, then into a clean inner bag. The inner bag is then repeatedly vacuum-filled with nitrogen until the oxygen content meets requirements before sealing. To prevent leakage and protect against light, the packaged inner bag is placed in an outer aluminum foil bag, which is then repeatedly vacuum-filled with nitrogen until the oxygen content meets requirements before sealing. However, this packaging method has the following problems:

[0004] 1. During the vacuum packaging of semiconductor wafers, the wafers are subjected to multiple vacuuming and nitrogen filling processes. Each time, the wafers are subjected to stress, and friction occurs between the carrier and the wafers, which can easily cause particles to fall off the wafer surface. Secondly, the internal stress of the wafers increases after being subjected to stress, which reduces the strength of the wafers and increases the risk of wafer breakage during packaging and transportation.

[0005] 2. When storing wafers in negative pressure packaging, the negative pressure causes the outgas in the wafer cassette or Cassette carrier and the inner and outer bags of the packaging to seep out more quickly, and this outgas can seriously contaminate the wafers.

[0006] 3. When the wafers are opened after being packaged under negative pressure, external air and particles can easily enter the wafer packaging box due to the negative pressure inside the packaging bag and contaminate the wafers.

[0007] 4. For wafers in negative pressure packaging, the inner and outer bags are tightly sealed, which can easily cause wrinkles at the seal, leading to air leakage. Summary of the Invention

[0008] In view of this, the present invention provides a positive pressure packaging method for semiconductor wafers to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A method for positive pressure packaging of semiconductor wafers includes the following steps:

[0011] S1: The wafers are placed into the inner bag. After polishing and cleaning, the wafers are inspected and placed into a clean carrier after passing inspection. The carrier containing the wafers is then placed into the clean inner bag.

[0012] S2: Ventilate the glove box by introducing nitrogen or argon into the glove box cavity and ensuring that the concentration of nitrogen or argon in the glove box cavity is greater than 99.95%.

[0013] S3: Place the inner bag into the glove box and let it stand. Then, place the inner bag from S1 into the glove box cavity through a clean transition chamber and let it stand. This allows the oxygen in the inner bag to be replaced by the nitrogen or argon in the glove box cavity, ensuring that the oxygen content in the inner bag is less than 0.5%.

[0014] S4: Pulse heat sealing. A pulse sealing machine is used inside the glove box to heat and seal the inner bag, completing the packaging.

[0015] Furthermore, the cleanliness level of the inner bag into which the wafers are placed in S1 is Class 100.

[0016] Furthermore, the inner bag in S1 is a plastic open bag for packaging 2-inch to 8-inch wafers.

[0017] Furthermore, the settling time in S3 is 10 min to 20 min.

[0018] Furthermore, the cleanliness level of the glove box cavity in S2 and S3 is Class 10, and the humidity is less than 1.0% RH.

[0019] Furthermore, the pressure of nitrogen or argon gas inside the glove box cavity in S3 and S4 is 5 to 10 mbar.

[0020] Furthermore, in S4, the pulse sealing machine heats and seals the inner bag for 0.5s to 1s.

[0021] The beneficial effects of this invention are as follows:

[0022] This invention does not apply negative pressure to the inner bag containing the wafers, thus avoiding issues such as wafer surface particle shedding, wafer deformation due to stress, sealing wrinkles and air leakage, and serious wafer contamination caused by Outgas seeping from the carrier and packaging bags. This invention uses pulse heating for sealing, resulting in good fusion quality of the inner bag sealing plastic. Furthermore, this invention has a simple process and a high cleanliness level. In S3 and S4, the pressure of nitrogen or argon in the glove box cavity is 5-10 mbar. When the sealed inner bag needs to be opened, the pressure of the inner bag is greater than the external atmospheric pressure, resulting in a small amount of nitrogen or argon being released, thus preventing the wafers from being contaminated by the external environment. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a flowchart of a positive pressure packaging method for semiconductor wafers according to the present invention. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0028] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0029] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0030] See appendix Figure 1 This invention discloses a positive pressure packaging method for semiconductor wafers, comprising the following steps:

[0031] S1: The wafers are placed into the inner bag. After polishing and cleaning, the wafers are inspected and placed into a clean carrier after passing inspection. The carrier containing the wafers is then placed into the clean inner bag.

[0032] S2: Ventilate the glove box by introducing nitrogen or argon into the glove box cavity and ensuring that the concentration of nitrogen or argon in the glove box cavity is greater than 99.95%.

[0033] S3: Place the inner bag into the glove box and let it stand. Then, place the inner bag from S1 into the glove box cavity through a clean transition chamber and let it stand. This allows the oxygen in the inner bag to be replaced by the nitrogen or argon in the glove box cavity, ensuring that the oxygen content in the inner bag is less than 0.5%.

[0034] This invention utilizes the theory of gas diffusion to replace vacuuming and nitrogen filling to achieve an oxygen content of less than 0.5% during semiconductor wafer packaging;

[0035] ①According to the diffusion theory of gases, all substances are constantly in irregular motion (kinetic theory of molecules); diffusion refers to the process by which molecules of a certain substance enter other substances through irregular motion and diffusion. Gas diffusion refers to the process by which molecules of a certain gas enter other gases through diffusion. Because the irregular motion of gas molecules is relatively intense, diffusion is relatively obvious.

[0036] ② When there is a high concentration of nitrogen or argon gas greater than 99.95% in the glove box cavity, and the oxygen content in the inner bag of S1 is 20% to 21% (equivalent to the oxygen content in the air), the inner bag is placed in the glove box cavity through the transition chamber. The high concentration of nitrogen or argon gas greater than 99.95% in the glove box cavity will undergo gas diffusion with the 20% to 21% oxygen in the inner bag.

[0037] S4: Pulse heating sealing. A pulse sealing machine is used inside the glove box cavity to heat and seal the inner bag, completing the packaging. This invention does not apply negative pressure to the inner bag containing the wafers, avoiding issues such as wafer surface particle shedding, wafer deformation due to stress, sealing wrinkles and air leakage, and serious wafer contamination from Outgas seeping from the carrier and packaging bags. This invention uses pulse heating sealing to ensure good plastic fusion quality at the inner bag seal, and the process is simple and has a high cleanliness level.

[0038] The cleanliness level of the wafers in S1 when they are placed into the inner bag is Class 100.

[0039] The inner bag in S1 is a plastic open bag for packaging 2-inch to 8-inch chips.

[0040] The settling time in S3 is 10 min to 20 min.

[0041] Through experiments, this invention has shown that plastic open bags containing 2-inch to 8-inch wafers are placed in the glove box cavity and left to stand for 10 to 20 minutes, with the oxygen content inside the plastic open bags being less than 0.5%.

[0042] The cleanliness level of the glove box cavity in S2 and S3 is Class 10, with a humidity of less than 1.0% RH. In this invention, the inner bag is placed inside the glove box cavity for gas replacement. Employees operate inside the glove box cavity while wearing clean, dust-free rubber gloves, reducing the oxygen content of the inner bag and sealing it. This avoids the cleanliness being affected by the materials and airflow ducts inside the packaging machine during negative pressure packaging. The cleanliness level during packaging with this invention can reach Class 10, and the risk of particles falling off the wafer surface is greatly reduced.

[0043] In S3 and S4, the pressure of nitrogen or argon in the glove box cavity is 5-10 mbar. When the sealed inner bag needs to be opened, the pressure of the inner bag is greater than the external atmospheric pressure, and a small amount of nitrogen or argon will be released to prevent the wafer from being contaminated by the external environment. In addition, the positive pressure of nitrogen or argon in the inner bag will inhibit the leakage of outgas, which can greatly reduce the risk of serious outgas contamination of the wafer.

[0044] The S4 pulse sealing machine heats and seals the inner bag in 0.5s to 1s, a very short heating time, resulting in good plastic fusion quality. Furthermore, this invention does not vacuum or fill the inner bag with nitrogen during packaging, preventing wrinkles and thus avoiding air leakage at the seal.

[0045] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for positive pressure packaging of semiconductor wafers, characterized in that, Includes the following steps: S1: The wafers are placed into the inner bag. After polishing and cleaning, the wafers are inspected and placed into a clean carrier after passing inspection. The carrier containing the wafers is then placed into the clean inner bag. S2: Ventilate the glove box by introducing nitrogen or argon into the glove box cavity and ensuring that the concentration of nitrogen or argon in the glove box cavity is greater than 99.95%. S3: Place the inner bag into the glove box and let it stand. Then, place the inner bag from S1 into the glove box cavity through a clean transition chamber and let it stand. This allows the oxygen in the inner bag to be replaced by the nitrogen or argon in the glove box cavity, ensuring that the oxygen content in the inner bag is less than 0.5%. S4: Pulse heat sealing. A pulse sealing machine is used inside the glove box to heat and seal the inner bag, completing the packaging.

2. The positive pressure packaging method for semiconductor wafers according to claim 1, characterized in that, The cleanliness level of the wafers placed in the inner bag in S1 is Class 100.

3. The positive pressure packaging method for semiconductor wafers according to claim 1, characterized in that, The inner bag in S1 is a plastic open bag for packaging 2-inch to 8-inch wafers.

4. The positive pressure packaging method for semiconductor wafers according to claim 3, characterized in that, The settling time in S3 is 10 min to 20 min.

5. The positive pressure packaging method for semiconductor wafers according to claim 1, characterized in that, The cleanliness level of the glove box cavity in S2 and S3 is Class 10, and the humidity is less than 1.0%RH.

6. The positive pressure packaging method for semiconductor wafers according to claim 1, characterized in that, The pressure of nitrogen or argon gas inside the glove box cavity in S3 and S4 is 5 to 10 mbar.

7. The positive pressure packaging method for semiconductor wafers according to claim 1, characterized in that, The pulse sealing machine in S4 heats and seals the inner bag for 0.5s to 1s.

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