Semiconductor photomask protective film injection molding box

Abstract

The utility model discloses a semiconductor photomask protective film injection molding box which comprises an upper cover and a lower cover split type sealing cavity. An airtight groove aligned with the center of the ejector pin is formed in an ejector pin contact area on the surfaces of the upper cover and the lower cover, the airtight groove is matched with the ejector pin in shape, area (1.5-3 times of the contact area of the ejector pin) and depth (0.1-0.3 mm), an edge arc chamfer is larger than or equal to 0.1 mm, and ejector pin traces are contained through integrated injection molding. After the cover is closed, a core sealing area is a groove peripheral flat surface (the proportion is larger than 80%), the flatness error is smaller than or equal to 5 micrometers, the vacuum degree is smaller than or equal to 10 Pa, and particulate pollutants are effectively blocked. The grooves of the upper cover and the lower cover are symmetrically arranged and share a mold, the assembly efficiency is improved by 30%, the yield reaches 95% or above, the structure is suitable for semiconductor precision packaging, and the airtight defect caused by traditional ejector pin traces is overcome.

Description

A semiconductor photomask protective film injection molding box Technical Field

[0001] This utility model relates to the semiconductor field, and in particular to a semiconductor photomask protective film injection molding box. Background Technology

[0002] In the semiconductor manufacturing industry, semiconductor photomask protective films are core precision components in the photolithography process, and their packaging requires stringent requirements for high airtightness and high cleanliness. The packaging boxes for semiconductor photomask protective films must ensure an internal vacuum environment during transportation and storage to prevent the intrusion of external particulate contaminants, thus avoiding impacts on the optical performance of the photomask and chip manufacturing yield.

[0003] The following key issues are faced in the production of semiconductor photomask protective film shipping boxes using traditional injection molding processes:

[0004] Air tightness defects caused by the demolding process: After injection molding, to prevent the workpiece from sticking to the mold, it needs to be pushed out of the mold by ejector pins (thimbles). If the workpiece material (such as antistatic ABS, PC plastic) is still in a molten state at high temperature during demolding, the ejector pins will leave protrusions or indentations (pin marks) on the workpiece surface, resulting in flatness deviations (error ≥ 0.1mm) on the sealing surface when the upper and lower covers are closed. This defect directly causes insufficient air tightness of the box, making it impossible to maintain a vacuum environment (the vacuum degree of traditional solutions is usually > 50Pa). External air and particulate contaminants can easily enter through the gaps, affecting the cleanliness of the product. Existing technology CN222290865U points out that traditional injection molds cause obvious defects on the product surface due to ejector pin marks. Although improving the ejector pin assembly design can reduce ejector pin marks, it does not completely eliminate the impact of flatness deviations on air tightness performance.

[0005] Semiconductor photomask protective films are extremely sensitive to particulate contamination (e.g., particles larger than 0.5μm can cause defects in the photolithography pattern). Traditional shipping boxes suffer from poor airtightness due to ejector pin marks, significantly increasing the risk of particle intrusion. This necessitates frequent cleaning or scrapping of the boxes, leading to increased production costs (defect rates can reach 20%-30%) and making it difficult to meet the packaging cleanliness requirements (ISO 14644-1 Class 5) of advanced processes such as EUV lithography.

[0006] Existing solutions attempt to eliminate pinholes through post-processing surface grinding or to fill gaps by adding adhesive strips for sealing. However, grinding processes are costly, inefficient, and may compromise the structural strength of the housing. Furthermore, adding seals increases assembly complexity and is prone to airtightness degradation due to aging, making them unsuitable for the long-term storage requirements of semiconductors. Summary of the Invention

[0007] The objective of this invention is to provide a semiconductor photomask protective film injection molding box. Through the semiconductor photomask protective film injection molding box, the needle points can be accommodated by the airtight groove, so as to solve the flatness deviation of the sealing surface when the upper and lower covers are closed.

[0008] According to this utility model, the task is accomplished through a semiconductor photomask protective film injection molding box, characterized in that it comprises:

[0009] The main body consists of two parts: an upper cover and a lower cover. When the upper cover and the lower cover are closed, they form a closed space.

[0010] Needle points are located on the inner or outer surfaces of the upper and lower covers; and

[0011] An airtight groove is provided to accommodate the needle point.

[0012] In one embodiment of this utility model, the upper cover and the lower cover share an airtight groove.

[0013] In one embodiment of this utility model, the edge of the airtight groove has a rounded chamfer.

[0014] In one embodiment of this utility model, the depth of the airtight groove is greater than or equal to the height of the needle point.

[0015] In one embodiment of this utility model, the semiconductor photomask protective film injection molding box is made of antistatic PC or ABS material.

[0016] In one embodiment of this utility model, the airtight groove and the main body are integrally injection molded.

[0017] In one embodiment of this utility model, the cross-sectional shape of the needle point is circular, elliptical, or square.

[0018] In one embodiment of this utility model, the airtight groove is symmetrical to the center of the needle point, and the center of the airtight groove coincides with the center of the needle point.

[0019] In one embodiment of this utility model, the radius of the rounded chamfer is greater than 0.1 mm.

[0020] This utility model has at least the following beneficial effects:

[0021] (1) This utility model provides an airtight groove at the corresponding position of the pin point. Through structural design, the protruding part of the pin is embedded in the groove, avoiding direct impact on the flatness of the box surface. The groove is symmetrical to the pin point and has a large area, ensuring that the pin mark is accommodated, while reducing the loss of the plane contact area and maintaining a tight fit when the lid is closed.

[0022] (2) The upper and lower covers of this utility model can share the same airtight groove design, eliminating the need to develop separate molds for different parts, thus reducing design complexity and manufacturing costs. The shape and size of the groove can be flexibly adjusted to accommodate different ejector pin layouts, improving the versatility of the solution. Attached Figure Description

[0023] Figure 1 shows a schematic diagram of the top cover structure of the semiconductor photomask protective film injection molding box in one embodiment of the present invention. Detailed Implementation

[0024] In the following description, the present invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive aspects of the present invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the present invention. However, the present invention is not limited to these specific details.

[0025] In this utility model, the various embodiments are merely intended to illustrate the solution of this utility model and should not be construed as limiting.

[0026] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to all of the same embodiment.

[0027] Furthermore, the numbering of the steps in the methods of this invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps may be executed in different orders.

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] The pin-point structure on the surface of the upper and lower covers of injection molded boxes in existing technology originates from the columnar ejector pin components in the injection mold. During the demolding process after injection molding, the ejector pin, as the core component of the demolding process, acts on the workpiece at a high temperature (such as molten or semi-molten antistatic ABS or PC plastic) through mechanical pushing force, forcing the workpiece to separate from the mold, thereby avoiding sticking and ensuring the continuity of the production process. However, this necessary demolding operation leaves pin-point marks on the workpiece surface that are completely consistent with the contour of the ejector pin head—typically circular or square protrusions, with a height usually between 0.1-0.3 mm. Since the semiconductor photomask protective film shipping box requires extremely high flatness of the sealing surface after the upper and lower covers are closed (the error must be controlled within ≤5μm), these pin-point marks can cause a significant flatness deviation of ≥0.1 mm on the sealing surface, thus forming air leakage gaps that are invisible to the naked eye but sufficient to compromise airtightness. Actual test data shows that the vacuum level inside the traditional structure box is generally higher than 50Pa, which significantly increases the risk of intrusion of particulate contaminants with a particle size ≥0.5μm, making it difficult to meet the stringent requirements of ISO 14644-1 Class 5 cleanliness (particle filtration efficiency ≥99.9%) for semiconductor precision packaging scenarios.

[0030] Figure 1 shows a schematic diagram of the top cover structure of the semiconductor photomask protective film injection molding box in one embodiment of the present invention.

[0031] As shown in Figure 1, to address the airtightness defects caused by ejector pin marks in existing technologies, this invention provides a dedicated airtight groove 104 directly below pin points 101, 102, and 103. The design of this groove follows a strict geometric matching principle: its center is perfectly aligned with the center of the ejector pin, its shape corresponds one-to-one with the outline of the ejector pin head (for example, a circular ejector pin corresponds to a circular groove with a diameter 0.5-1mm larger, and a square ejector pin corresponds to a rectangular groove with each side length increased by 0.5mm), its area is 1.5-3 times the contact area of ​​the ejector pin, and its depth precisely matches the maximum height of the pin point (typically 0.1-0.3mm), ensuring that the ejector pin protrusion is completely accommodated within the groove. The groove edge adopts a rounded chamfer design with a radius ≥0.1mm, effectively preventing material accumulation at the corners during injection molding and reducing stress concentration during cap closure. The attached figure shows the upper cap portion; the lower cap portion can share the same airtight groove without requiring additional design.

[0032] The airtight groove 104 is integrally formed with the upper and lower cover bodies 100 through the recessed structure of the injection mold, requiring no additional processing steps. Its core function is to create a "pin mark isolation zone": when the upper and lower covers are closed, the pin mark protrusion is confined inside the groove, and the surface of this area is lower than the overall sealing surface, thereby controlling the flatness error of the sealing surface within ≤5μm. Actual testing has verified that the vacuum level inside the box using this structure can be stably maintained at ≤10Pa, an improvement of more than 80% compared to traditional solutions, effectively blocking the intrusion path of particulate contaminants. It is worth noting that the groove adopts a non-contact design; its localized area only reduces the contact area by ≤20%, while the continuous flat surface of ≥80% on the periphery constitutes the main sealing surface, ensuring that the overall effective sealing area is ≥90% of the theoretical value, balancing the requirements of structural avoidance and sealing performance.

[0033] In this embodiment, the upper and lower cover bodies are made of high-temperature resistant engineering plastics (such as antistatic ABS and PC) as the base material, and are formed by precision injection molding. The surface flatness meets the semiconductor-grade precision requirements (flatness ≤ 5μm). The sealed cavity formed after the covers are closed is designed for precision devices such as semiconductor photomask protective films. Its edges are provided with a continuous planar sealing area with a width of 3-5mm. The surface roughness Ra of this area is ≤ 1.6μm, which can provide uniform sealing contact pressure. The airtight grooves 104 of the upper and lower covers adopt a mirror symmetrical design and are formed synchronously by the upper and lower cavities of the same mold. There is no need to design separate mold structures, which significantly reduces mold development costs (reducing the number of molds by 50%) and production cycle (shortening the R&D time by 20%-30%). During the closing process, the geometric symmetry of the groove position can achieve automatic alignment, avoiding assembly misalignment caused by the difference between the upper and lower covers in traditional structures. At the same time, it ensures uniform pressure distribution on the sealing surface (pressure difference ≤ 0.5Pa). Even after more than 500 repeated opening and closing cycles, the air density of the box remains stable, extending the service life to more than 5 years, fully meeting the reliability requirements of long-term storage and transportation of semiconductor devices.

[0034] Although various embodiments of the present invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made thereto without departing from the spirit and scope of the present invention. Therefore, the breadth and scope of the present invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A semiconductor photomask protective film injection molding box, characterized in that, include: The main body consists of two parts: an upper cover and a lower cover. When the upper cover and the lower cover are closed, they form a closed space. Needle points are located on the inner or outer surfaces of the upper and lower covers; and airtight grooves are provided corresponding to the needle points to accommodate them.

2. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The upper and lower covers share an airtight groove.

3. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The edge of the airtight groove has a rounded chamfer.

4. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The depth of the airtight groove is greater than or equal to the height of the needle point.

5. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The semiconductor photomask protective film injection molding box is made of antistatic PC or ABS material.

6. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The airtight groove is integrally injection molded with the main body.

7. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The cross-sectional shape of the needle point is circular, elliptical, or square.

8. The semiconductor photomask protective film injection molding box according to claim 1, characterized in that, The airtight groove is symmetrical to the center of the needle point, and the center of the airtight groove coincides with the center of the needle point.

9. The semiconductor photomask protective film injection molding box according to claim 3, characterized in that, The radius of the rounded chamfer is greater than 0.1 mm.

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