Jig for overcoming warping of substrate

Abstract

The utility model provides a jig for overcoming warping of a substrate, which comprises an upper module and a lower module, the upper module comprises an upper cover plate and a plurality of magnetic strips, the upper cover plate is provided with a plurality of unit windows, the unit windows are used for exposing a mounting area of the substrate, and the magnetic strips are fixedly arranged on the lower surface of the upper cover plate and extend along the transverse direction or the longitudinal direction at the outer edges of the unit windows; the lower module is arranged below the upper module, the lower module comprises a base, the base is provided with a plurality of bearing grooves and a plurality of accommodating grooves, the bearing grooves correspond to the unit windows and are used for bearing substrates, and the accommodating grooves correspond to the magnetic strips and are used for accommodating and magnetically attracting the magnetic strips; when the upper module and the lower module are buckled, the magnetic strips are inserted and magnetically attracted in the accommodating grooves, so that the outer edges of the unit windows can abut against the outer edge of the substrate. The jig can effectively press the substrate, so that the warping of the substrate is greatly reduced, and the yield of packaged products is improved.

Description

Technical Field

[0001] The utility model relates to the field of semiconductor packaging, in particular to a fixture for overcoming substrate warping. Background Art

[0002] With the improvement of the requirements for the performance of packaging structures, the number of Chiplets integrated in 2.5D & 3D packaging units is continuously increasing. The thickness and size of the substrate of Flip Chip Ball Grid Array (FCBGA) packaging are also continuously increasing, and the substrate warping phenomenon is becoming more serious. At present, in the FCBGA manufacturing process for the substrate warping phenomenon, in the flip-chip reflow process, a magnetic fixture is generally used to increase the pressing force on the substrate and reduce the substrate warping. Traditional magnetic fixtures usually consist of a magnetic base and a non-magnetic stainless steel cover plate. The magnetism is obtained by small magnets embedded in the base. Too many embedded small magnets will affect the flatness of the base, thereby affecting the pressing of the substrate by the fixture. When the number of embedded small magnets is insufficient, due to the deformation of the stainless steel cover plate when heated, insufficient attraction cannot be provided to the stainless steel cover plate, so that the warped substrate cannot be effectively pressed, bringing a serious bridging risk to the flip-chip solder bumps and directly affecting the product quality. Summary of the Invention

[0003] The technical problem to be solved by the utility model is to provide a fixture for overcoming substrate warping, which can effectively press the substrate, greatly reduce the warping of the substrate, and improve the yield of the packaged product.

[0004] To solve the above problems, an embodiment of the utility model provides a fixture for overcoming substrate warping, including: an upper module, including an upper cover plate and a plurality of magnetic strips, the upper cover plate has a plurality of unit windows for exposing the mounting area of the substrate, the magnetic strips are fixedly arranged on the lower surface of the upper cover plate and extend horizontally or vertically along the outer edge of the unit window; a lower module, arranged below the upper module, the lower module includes a base, the base has a plurality of bearing grooves and a plurality of receiving grooves, the bearing grooves correspond to the unit windows for bearing the substrate, and the receiving grooves correspond to the magnetic strips for receiving and magnetically attracting the magnetic strips; when the upper module and the lower module are buckled, the magnetic strips are inserted and magnetically attracted into the receiving grooves, so that the outer edge of the unit window can press against the outer edge of the substrate.

[0005] In one embodiment, at least a part of the magnetic strips span at least two of the unit windows.

[0006] In one embodiment, the width of the accommodating groove is greater than or equal to the width of the magnetic strip, and the depth of the accommodating groove is greater than or equal to the height of the magnetic strip.

[0007] In one embodiment, the upper mold assembly further includes a plurality of pressure members, which are arranged on the upper surface of the cover plate and located at the outer edge of the unit window. When the upper mold assembly is buckled with the lower mold assembly, the pressure members can be located above the outer edge of the substrate to apply pressure to the outer edge of the substrate.

[0008] In one embodiment, the pressure piece is an annular pressure piece, and an opening of the annular pressure piece corresponds to the unit window.

[0009] In one embodiment, the opening of the annular pressure member overlaps with the cell window.

[0010] In one embodiment, the opening size of the annular pressure member is larger than the size of the unit window.

[0011] In one embodiment, the annular pressure member has a ring width of 20 to 50 mm.

[0012] In one embodiment, a plurality of the pressure members are spaced apart around the outer edge of the unit window.

[0013] In one embodiment, the pressure member and the magnetic strip are staggered in a direction perpendicular to the upper cover plate.

[0014] In the jig for overcoming substrate warping provided by the embodiment of the present invention, a magnetic strip extending horizontally or vertically is provided on the outer edge of the unit window of the upper module, and the base of the lower module is fixed to the upper module by magnetic attraction through the magnetic strip, thereby enabling the upper module and the lower module to cooperate to achieve compression of the substrate. Compared with the prior art which uses small magnetic blocks embedded in the base of the lower module to achieve magnetic attraction, in the jig for overcoming substrate warping provided by the embodiment of the present invention, the magnetic attraction component is fixed on the surface of the upper cover plate in the form of a magnetic strip, without the need to embed the base, and the magnetic strip is a continuous structure extending horizontally or vertically, thereby avoiding the problem of uneven base caused by small magnetic blocks embedded at multiple points, thereby increasing the fit between the upper module and the lower module, and enhancing the effective compression of the substrate; and, the magnetic strip is a continuous structure, and its magnetic attraction strength is greater, further increasing the effective compression of the substrate; the jig for overcoming substrate warping provided by the embodiment of the present invention effectively reduces substrate warping, which is conducive to improving the yield rate of packaged products. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] To more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the attached drawings required for the description of the embodiments. Obviously, the attached drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other attached drawings can be obtained based on these attached drawings.

[0016] Figure 1A is a schematic cross-sectional view of a jig for overcoming substrate warping provided by the first embodiment of the present utility model;

[0017] Figure 1B is a schematic cross-sectional view of placing a substrate in a jig for overcoming substrate warping provided by the first embodiment of the present utility model;

[0018] Figure 2 is a schematic top view of an upper module of a jig for overcoming substrate warping provided by the first embodiment of the present utility model;

[0019] Figure 3 is a schematic bottom view of an upper module of a jig for overcoming substrate warping provided by the first embodiment of the present utility model;

[0020] Figure 4 is a schematic top view of a lower module of a jig for overcoming substrate warping provided by the first embodiment of the present utility model;

[0021] Figure 5 is a schematic cross-sectional view of a jig for overcoming substrate warping provided by the second embodiment of the present utility model;

[0022] Figure 6 is a schematic top view of an upper module of a jig for overcoming substrate warping provided by the second embodiment of the present utility model;

[0023] Figure 7 is a schematic bottom view of an upper module of a jig for overcoming substrate warping provided by the second embodiment of the present utility model;

[0024] Figure 8 is a schematic cross-sectional view of a jig for overcoming substrate warping provided by the third embodiment of the present utility model;

[0025] Figure 9 is a schematic top view of an upper module of a jig for overcoming substrate warping provided by the fourth embodiment of the present utility model. Specific Embodiments

[0026] The following makes a detailed description of the specific embodiments of the jig for overcoming substrate warping provided by the present utility model in conjunction with the attached drawings.

[0027] Figure 1A is a schematic cross-sectional view of a jig for overcoming substrate warping provided by the first embodiment of the present utility model,Figure 1B It is a schematic cross-sectional view of placing a substrate in a jig for overcoming substrate warping provided by the first embodiment of the present utility model. Please refer to Figure 1A and Figure 1B , the jig includes: an upper module 100, which includes an upper cover plate 110 and a plurality of magnetic strips 120. The upper cover plate 110 has a plurality of unit windows 111, and the unit windows 111 are used to expose the mounting area of the substrate 300. The magnetic strips 120 are fixedly arranged on the lower surface of the upper cover plate 110 and extend horizontally or vertically at the outer edge of the unit window 111; a lower module 200, which is arranged below the upper module 100. The lower module 200 includes a base 210. The base 210 has a plurality of carrying grooves 211 and a plurality of accommodating grooves 212. The carrying grooves 211 correspond to the unit windows 111 and are used to carry the substrate 300. The accommodating grooves 212 correspond to the magnetic strips 120 and are used to accommodate and magnetically attract the magnetic strips 120. When the upper module 100 and the lower module 200 are buckled, the magnetic strips 120 are inserted and magnetically attracted into the accommodating grooves 212, so that the outer edge of the unit window 111 can press against the outer edge of the substrate 300.

[0028] In the jig for overcoming substrate warping provided by the embodiment of the present utility model, a magnetic strip 120 extending horizontally or vertically is arranged at the outer edge of the unit window 111 of the upper module 100. The base 210 of the lower module 200 is magnetically fixed to the upper module 100 through the magnetic strip 120, and then the upper module 100 and the lower module 200 cooperate to realize the pressing of the substrate 300. Compared with the magnetic attraction realized by small magnetic blocks buried in the base 210 of the lower module 200 in the prior art, in the jig for overcoming substrate warping provided by the embodiment of the present utility model, the magnetic attraction member is fixedly arranged on the surface of the upper cover plate 110 in the form of a magnetic strip 120, without being buried in the base 210 and the magnetic strip 120 is a continuous structure extending horizontally or vertically, avoiding the problem of unevenness of the base 210 caused by multiple small magnetic blocks buried, thereby increasing the fitting degree between the upper module 100 and the lower module 200 and enhancing the effective pressing of the substrate 300; and, the magnetic strip 120 is a continuous structure, and its magnetic attraction intensity is greater, further increasing the effective pressing of the substrate 300. The jig for overcoming substrate warping provided by the embodiment of the present utility model effectively reduces the warping of the substrate 300 and is beneficial to improving the yield of the packaging product.

[0029] Figure 2 It is a top view schematic diagram of the upper module 100 of the jig for overcoming substrate warping provided by the first embodiment of the present utility model. Figure 3 It is a bottom view schematic diagram of the upper module 100 of the jig for overcoming substrate warping provided by the first embodiment of the present utility model. In Figure 2In [the figure], the magnetic strip 120 is blocked by the upper cover plate 110, so the magnetic strip 120 is schematically shown by a dashed line.

[0030] Please refer to Figures 1A to 3 , the upper cover plate 110 has a plurality of the unit windows 111, the plurality of the unit windows 111 are distributed in a matrix, each of the unit windows 111 penetrates through the upper cover plate 110, and the unit window 111 is used to expose the mounting area of the substrate 300. In some embodiments, when devices such as chips are mounted on the mounting area of the substrate 300, the unit window 111 exposes the device, and the device can pass through the unit window 111.

[0031] The magnetic strip 120 is fixedly arranged on the lower surface of the upper cover plate 110, that is, the magnetic strip 120 is fixedly arranged on the surface of the upper cover plate 110 facing the lower module 200, so that when the upper module 100 is buckled with the lower module 200, the magnetic strip 120 can be inserted into the receiving groove 212. In some embodiments, the magnetic strip 120 is fixed on the lower surface of the upper cover plate 110 through a fastener 130, and the fastener 130 includes but is not limited to fastening screws and the like. The number of the magnetic strips 120 can be increased or decreased according to design requirements.

[0032] At the outer edge of the unit window 111, the magnetic strip 120 extends horizontally or vertically, that is, on the lower surface of the upper cover plate 110, the magnetic strip 120 extends horizontally or vertically in the non-unit window 111 area. For example, in the non-unit window 111 area on the lower surface of the upper cover plate 110, a part of the magnetic strip 120 extends in the X direction, and another part of the magnetic strip 120 extends in the Y direction.

[0033] The distribution of the magnetic strip 120 on the lower surface of the upper cover plate 110 can be set according to design requirements. In one embodiment, at least a part of the magnetic strip 120 straddles at least two of the unit windows 111, that is, among all the magnetic strips 120, one or more of the magnetic strips 120 straddle at least two of the unit windows 111. The magnetic strip 120 straddling at least two of the unit windows 111 means that the same magnetic strip 120 is arranged at the outer edges of at least two of the unit windows 111. This embodiment further avoids the unevenness of the base 210 by increasing the length of the magnetic strip 120, and increases the magnetic attraction intensity of the magnetic strip 120, further increasing the effective pressing force on the substrate 300.

[0034] Figure 4 is a top view schematic diagram of the lower module 200 in the fixture for overcoming substrate warping provided by the first embodiment of the present invention. Please refer to Figures 1A to 4, the lower module 200 is disposed below the upper module 100, and the upper module 100 is disposed above the lower module 200. In the embodiments of the present invention, the terms "above" and "below" are used to represent the relative positions of the lower module 200 and the upper module 100. For example, in this embodiment, the terms "above" and "below" refer to the arrangement of the upper module and the lower module in the Z direction.

[0035] The lower module 200 includes a base 210, and the base 210 has a plurality of carrying grooves 211 and a plurality of receiving grooves 212.

[0036] The carrying groove 211 is a groove recessed toward the inside of the base 210, and is used for carrying the substrate 300. In the encapsulation process, for example, in the flip-chip reflow (FC reflow) step, the substrate 300 is placed in the carrying groove 211, and the upper module 100 and the lower module 200 are fastened together to apply pressure to the substrate 300, thereby preventing the substrate 300 from warping. In some embodiments, the plurality of carrying grooves 211 are arranged in a matrix.

[0037] In some embodiments, the depth of the carrying groove 211 is less than the thickness of the substrate 300, that is, when the substrate 300 is placed in the carrying groove 211, the upper surface of the substrate 300 protrudes from the upper edge of the carrying groove 211, so that after the upper module 100 and the lower module 200 are fastened together, the upper cover plate 110 can press against the substrate 300. In one embodiment, the difference between the depth of the carrying groove 211 and the thickness of the substrate 300 is 300-400 μm.

[0038] In some embodiments, the size of the carrying groove 211 is larger than the size of the substrate 300. Specifically, the length of the carrying groove 211 in the transverse direction (for example, the X direction) is greater than the length of the substrate 300 in the transverse direction (for example, the X direction), and the length of the carrying groove 211 in the longitudinal direction (for example, the Y direction) is greater than the length of the substrate 300 in the longitudinal direction (for example, the Y direction), so as to facilitate the placement of the substrate 300 into the carrying groove 211. For example, in one embodiment, the difference between the length of the carrying groove 211 in the transverse direction (for example, the X direction) and the length of the substrate 300 in the transverse direction (for example, the X direction) is 0.1-0.2 mm, and the difference between the length of the carrying groove 211 in the longitudinal direction (for example, the Y direction) and the length of the substrate 300 in the longitudinal direction (for example, the Y direction) is 0.1-0.2 mm.

[0039] The carrying groove 211 corresponds to the unit window 111. For example, the carrying groove 211 corresponds to the unit window 111 one by one, and the mounting area of the substrate 300 located in the carrying groove 211 is exposed to the unit window 111 corresponding to the carrying groove 211. In some embodiments, the size of the carrying groove 211 is larger than the size of the unit window 111, so that the upper cover plate 110 can press against the outer edge of the substrate 300. Specifically, the length of the carrying groove 211 in the transverse direction (e.g., the X direction) is greater than the length of the unit window 111 in the transverse direction (e.g., the X direction), and the length of the carrying groove 211 in the longitudinal direction (e.g., the Y direction) is greater than the length of the unit window 111 in the longitudinal direction (e.g., the Y direction), so that the upper cover plate 110 can press against the outer edge of the substrate 300.

[0040] The receiving groove 212 is a groove recessed towards the inside of the base 210. The receiving groove 212 is provided on the periphery of the carrying groove 211, and its setting position corresponds to the setting position of the magnetic strip 120. After the upper module 100 and the lower module 200 are buckled, the magnetic strip 120 is inserted and magnetically attracted into the receiving groove 212 to fix the upper cover plate 110 and the base 210. The outer edge of the unit window 111 can press against the outer edge of the substrate 300, thereby suppressing the warping of the substrate 300. In one embodiment, the width of the receiving groove 212 is greater than or equal to the width of the magnetic strip 120 to prevent the width of the magnetic strip 120 from being too wide and affecting the flatness of the base 210. In one embodiment, the depth of the receiving groove 212 is greater than or equal to the height of the magnetic strip 120, so that the magnetic strip 120 can be fully inserted into the receiving groove 212, avoiding the magnetic strip 120 not being fully inserted and forming a gap between the upper cover plate 110 and the base 210, and this gap may cause the upper cover plate 110 to be unable to press against the substrate 300.

[0041] In some embodiments, the base 210 is a base 210 that can be magnetically attracted by the magnetic strip 120. For example, in one embodiment, the base 210 is a stainless steel base 210, and in another embodiment, the base 210 is an alloy base 210. The magnetic strip 120 magnetically attracts the base 210 in the receiving groove 212, thereby fixing the upper cover plate 110 and the base 210.

[0042] In the above embodiments, the jig overcomes the warping of the substrate 300 by the upper cover plate 110 pressing against the outer edge of the substrate 300. In order to further increase the pressing force on the substrate 300, another embodiment of the present invention also provides a jig. Figure 5It is a schematic cross-sectional view of a jig for overcoming substrate warping provided by the second embodiment of the present utility model. Figure 6 It is a top view schematic diagram of the upper module 100 of the jig for overcoming substrate warping provided by the second embodiment of the present utility model. Figure 7 It is a bottom view schematic diagram of the upper module 100 of the jig for overcoming substrate warping provided by the third embodiment of the present utility model.

[0043] Please refer to Figures 5 to 7 , the difference between this embodiment and the first embodiment is that the upper module 100 further includes a plurality of pressure members 500, the pressure members 500 are arranged on the upper surface of the upper cover plate 110 and are located at the outer edge of the unit window 111. When the upper module 100 is buckled with the lower module 200, the pressure members 500 can be located above the outer edge of the substrate 300 for applying pressure to the outer edge of the substrate 300. In this embodiment, by arranging the pressure members 500, the pressing force of the upper cover plate 110 on the substrate 300 is further increased, and the warping of the substrate 300 is further effectively reduced. In some embodiments, by adjusting the weight or height of the pressure members 500, etc., the pressing force of the upper cover plate 110 on the substrate 300 is changed, and thus the dynamic adjustment of the pressure can be realized according to the actual state of the substrate 300, and the warping of the substrate 300 is further effectively reduced. The pressure members 500 are fixed on the upper surface of the upper cover plate 110 through fasteners 510, and the fasteners 510 include but are not limited to fastening screws. In Figure 6 , the magnetic strip 120 is blocked by the upper cover plate 110, so the magnetic strip 120 is schematically shown by a dashed line. In Figure 7 , the pressure members 500 are blocked by the upper cover plate 110, so the pressure members 500 are schematically shown by a dashed line.

[0044] In some embodiments, as Figure 6 shown, the pressure member 500 is an annular pressure member, and the opening 501 of the annular pressure member corresponds to the unit window 111. That is, in one embodiment, the shape of the pressure member 500 is a closed ring, and the opening of the ring in the longitudinal direction (for example, the Y direction) corresponds to the unit window 111 so that the devices in the chip mounting area of the substrate 300 can be exposed to the opening. The annular pressure member can apply uniform pressure to the edge of the substrate 300, further avoiding the warping of the substrate 300. In some embodiments, the ring width of the annular pressure member is 20-50 mm.

[0045] In some embodiments, as Figure 5 shown, the opening 501 of the annular pressure member overlaps with the unit window 111, that is, the size of the opening 501 of the annular pressure member is the same as the size of the unit window 111; in other embodiments, as Figure 8As shown, it is a cross-sectional schematic diagram of a jig for overcoming substrate warping provided in the third embodiment of the present invention. The size of the opening 501 of the annular pressure member is larger than the size of the unit window 111, that is, the projection area of the opening 501 of the annular pressure member on the substrate 300 is larger than the projection area of the unit window 111.

[0046] In the above embodiment, the pressure member 500 is a continuous ring structure. In other embodiments, a plurality of pressure members 500 are spaced around the outer edge of the unit window 111, that is, the pressure member 500 is a discontinuous structure. Figure 9 As shown, it is a top view schematic diagram of the upper mold assembly 100 in the jig for overcoming substrate warping provided in the fourth embodiment of the present invention. In this embodiment, a plurality of pressure members 500 are spaced around the outer edge of the unit window 111 to provide pressing force to the outer edge of the substrate 300.

[0047] In one embodiment, in a direction perpendicular to the upper cover plate 110 (e.g., the Z direction), the pressure member 500 and the magnetic strip 120 are staggered, so as to apply pressure to different areas of the lower mold 200, further improving the fastening of the upper mold 100 and the lower mold 200, thereby further increasing the pressing force on the substrate 300. Specifically, please refer to Figure 5 In the direction perpendicular to the upper cover 110 (for example, the Z direction), the pressure piece 500 and the magnetic strip 120 are staggered, and the magnetic strip 120 is located on the periphery of the pressure piece 500. In the area where the magnetic strip 120 is located, the upper cover 110 is adhered to the base 210 under the magnetic attraction of the magnetic strip 120. In the area where the pressure piece 500 is located, the upper cover 110 is adhered to the base 210 under the action of the gravity of the pressure piece 500, thereby increasing the pressing force of the upper cover 110 on the substrate 300, effectively reducing the warping of the substrate 300, and facilitating improving the yield rate of the packaged products.

[0048] The fixture for overcoming substrate warping provided by the embodiment of the present invention increases the fit between the upper module 100 and the lower module 200, enhances the effective pressing of the substrate 300, effectively reduces the warping of the substrate 300, and is conducive to improving the yield rate of packaged products.

[0049] It should be noted that the terms "including" and "having" and their variants in the documents of the present utility model are intended to cover non-exclusive inclusion. The terms "first", "second", etc. are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. Unless the context clearly indicates otherwise, it should be understood that the data used in this way can be interchanged under appropriate circumstances. The term "one or more" depends at least in part on the context and can be used to describe a feature, structure, or property in a singular sense or can be used to describe a combination of features, structures, or features in a plural sense. The term "based on" can be understood as not necessarily intended to express a set of exclusive factors, but rather, alternatively, also at least in part depending on the context, allowing for other factors that may not be explicitly described. Additionally, without conflict, the embodiments in the present utility model and the features in the embodiments can be combined with each other. Furthermore, in the above description, the description of well-known components and technologies is omitted to avoid unnecessarily confusing the concepts of the present utility model. In each of the above embodiments, what each embodiment focuses on explaining is the difference from other embodiments. For the same / similar parts among the various embodiments, reference can be made to each other.

[0050] The above are only the preferred embodiments of the present utility model. It should be pointed out that for those of ordinary skill in the art of this technology, without departing from the principle of the present utility model, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A fixture for overcoming substrate warping, characterized in that, include: An upper module, comprising an upper cover plate and a plurality of magnetic strips, wherein the upper cover plate has a plurality of unit windows, the unit windows being used to expose the mounting area of the substrate, the magnetic strips being fixedly disposed on the lower surface of the upper cover plate and extending horizontally or vertically at the outer edges of the unit windows; A lower mold assembly is provided below the upper mold assembly, the lower mold assembly includes a base, the base has a plurality of bearing grooves and a plurality of accommodating grooves, the bearing grooves correspond to the unit windows and are used to carry the substrate, and the accommodating grooves correspond to the magnetic strips and are used to accommodate and magnetically attract the magnetic strips; When the upper mold assembly is buckled with the lower mold assembly, the magnetic strip is inserted into and magnetically attracted into the accommodating groove, so that the outer edge of the unit window can press against the outer edge of the substrate.

2. The jig according to claim 1, wherein At least a portion of the magnetic stripe spans across at least two of the cell windows.

3. The jig according to claim 1, wherein The width of the accommodating groove is greater than or equal to the width of the magnetic strip, and the depth of the accommodating groove is greater than or equal to the height of the magnetic strip.

4. The jig according to claim 1, wherein The upper mold assembly also includes a plurality of pressure pieces, which are arranged on the upper surface of the cover plate and located at the outer edge of the unit window. When the upper mold assembly is buckled with the lower mold assembly, the pressure pieces can be located above the outer edge of the substrate to apply pressure to the outer edge of the substrate.

5. The jig according to claim 4, characterized in that, The pressure piece is an annular pressure piece, and an opening of the annular pressure piece corresponds to the unit window.

6. The jig according to claim 5, characterized in that, An opening of the annular pressure member overlaps with the cell window.

7. The jig according to claim 5, characterized in that, The opening size of the annular pressure piece is larger than the size of the unit window.

8. The jig according to claim 5, characterized in that, The ring width of the annular pressure piece is 20 to 50 mm.

9. The jig according to claim 5, wherein A plurality of pressure members are arranged at intervals around the outer edge of the unit window.

10. The jig according to claim 4, wherein, In a direction perpendicular to the upper cover plate, the pressure piece and the magnetic strip are staggered.

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