Photosensitive polyimide material with low glass transition temperature as well as preparation method and application thereof

Abstract

The invention provides a photosensitive polyimide material with low glass transition temperature and a preparation method and application thereof. The photosensitive polyimide material with low glass transition temperature is prepared from the following raw materials: dianhydride, diamine and a solvent, moreover, the dianhydride and / or the diamine are / is provided with functional groups with large free volumes. According to the present invention, by introducing the functional group having the large free volume into the diamine and / or the dianhydride, the glass transition temperature of the polyimide material can be effectively reduced, such that the material can be softened and bonded at the low temperature so as to be used as the single material of the temporary bonding layer and the laser stripping layer;

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and relates to a photosensitive polyimide material with a low glass transition temperature and a preparation method and application thereof. Background Art

[0002] Currently, most temporary bonding / debonding platforms on the market focus on multi-layer structures, such as dual-layer systems that include a temporary bonding layer and a peeling layer. The multi-step coating and baking of each layer leads to increased cost of ownership and reduced yield of the entire process. In contrast, by using a single material that can serve as both a temporary bonding layer and a laser peeling layer, costs can be greatly reduced and yields can be increased.

[0003] However, the resin types currently used in the development of two-in-one materials are mainly polyketamine, acrylic acid and other types, which have defects in chemical resistance and temperature resistance. Polyimide is better in chemical resistance, temperature resistance and photosensitivity, but the Tg (glass transition temperature) of polyimide is generally between 280 and 300°C, and it is difficult to bond a single layer of material. It needs to be matched with a bonding material with a lower Tg to bond with the substrate.

[0004] CN113439112A discloses a new material, polyketamine, which has high absorbance at multiple wavelengths, can effectively prevent device damage, and can be used in laser debonding and RDL processes. In addition, the material has high thermal stability, good adhesion, can be removed by dry etching, and can reduce stress and curvature. However, the material has the following disadvantages: dry etching is required after debonding, the cleaning rate is low, there is thermal stress, and high-density structures are difficult to clean.

[0005] CN106687541A discloses a temporary bonding method and product, wherein a polyimide peeling layer is used to promote the separation of the first and second substrates. The method includes applying a bonding layer on the back surface and the outermost edge of the first substrate, and forming a polyimide peeling layer on the device surface of the first substrate. The polyimide peeling layer is formed by a composition containing a polymer, and the polymer can be a fluorinated dianhydride, a photosensitive dianhydride, a photosensitive diamine, and a combination thereof. However, the polyimide peeling layer in the invention itself has no adhesiveness and needs to be used in conjunction with an adhesive material.

[0006] CN115943190A discloses the use of a bonding layer comprising polyazomethine, and the separation of the substrate is achieved by irradiation with laser energy. The material has the ability to be used as a single-layer system for debonding, and laser debonding is generally used as its peeling mechanism. These materials also allow solvent cleaning using very mild acidic conditions (rather than the typical harsh conditions for curable layers). Although the material disclosed in this invention is a two-in-one material, its chemical resistance is poor and it is not tolerant to strong acids.

[0007] Therefore, in the art, it is desired to develop a polyimide material with a low glass transition temperature to satisfy the requirement of being bondable at a relatively low temperature, so that it can be used as a single material that can be used as both a temporary bonding layer and a laser lift-off layer. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a photosensitive polyimide material with a low glass transition temperature and a preparation method and application thereof.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a photosensitive polyimide material with a low glass transition temperature, wherein the raw materials for preparing the photosensitive polyimide material with a low glass transition temperature include dianhydride, diamine and solvent;

[0011] Furthermore, the dianhydride and / or the diamine has a functional group having a large free volume.

[0012] The present invention can effectively reduce the glass transition temperature of the polyimide material by introducing functional groups with large free volume into diamine and / or dianhydride, so that the material can soften and bond at a lower temperature; because its structure has strong conjugation of benzene ring and imide ring, it has strong 355nm photosensitivity, so that it can be used as a single material that can be used as both a temporary bonding layer and a laser stripping layer.

[0013] Preferably, the functional group with a large free volume includes -CF 3 Any one of a functional group, a flexible siloxane group, a flexible long-chain aliphatic hydrocarbon group, or a combination of at least two thereof.

[0014] Preferably, the dianhydride includes any one of 9,9-bis(trifluoromethyl)-2.3.6,7-oxanthene tetracarboxylic dianhydride, hexafluoro dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 4,4'-oxydiphthalic anhydride (ODPA), and pyromellitic dianhydride, or a combination of at least two thereof.

[0015] Preferably, the diamine includes siloxane-containing monomers such as bis(p-aminophenoxy)dimethylsilane, 1,4-bis(aminobutyl)tetramethyldisiloxane, 1,3-bisaminopropyl-1,1,3,3-tetramethyldisiloxane, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)-(1,1-diphenyl)-4,4'-diamine and other monomers containing -CF3 functional groups, dodecyl diamine, hexamethylene diamine, 1,6-hexanediamine and other monomers containing long-chain aliphatic hydrocarbon groups, and 4,4'-diaminodiphenyl ether, any one or a combination of at least two thereof.

[0016] Preferably, the molar ratio of the dianhydride to the diamine is (0.9-1.1):1, for example 0.9:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1, 1:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1, 1.1:1, etc., as well as specific ratios between the above ratios. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific ratios included in the ratio range.

[0017] Preferably, the solvent includes any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, or a combination of at least two thereof. The solvent is used to dissolve the resin, which can effectively reduce the viscosity of the material and facilitate the degassing and processing of the material.

[0018] Preferably, based on the total weight of the raw materials for preparing the photosensitive polyimide material with a low glass transition temperature as 100%, the amount of the solvent used is 40% to 95%, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, preferably 85% to 95%.

[0019] Preferably, the raw materials for preparing the photosensitive polyimide material with a low glass transition temperature further include an auxiliary agent.

[0020] Preferably, the auxiliary agent includes a leveling agent, which can help the polyimide material form a flat, smooth and uniform coating film during the drying and film-forming process.

[0021] Preferably, the leveling agent includes but is not limited to silicone leveling agent and / or fluorocarbon leveling agent and other leveling agents that can withstand high temperatures.

[0022] Preferably, the organosilicon leveling agent includes any one of polydimethylsiloxane, polymethylalkylsiloxane, and organic modified polysiloxane, or a combination of at least two thereof.

[0023] Preferably, the fluorocarbon leveling agent includes oily leveling agents such as A-3038 and / or FCF-203.

[0024] Preferably, the glass transition temperature of the photosensitive polyimide material with a low glass transition temperature is below 275°C, for example 273°C, 270°C, 260°C, 250°C, 240°C, 230°C, 220°C, 210°C, etc., as well as specific point values ​​between the above point values. Due to limited space and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, preferably 200-250°C.

[0025] In a second aspect, the present invention provides a method for preparing the photosensitive polyimide material with a low glass transition temperature as described in the first aspect, the preparation method comprising the following steps:

[0026] (1) mixing dianhydride and a solvent, stirring until the dianhydride is completely dissolved, cooling, and then adding diamine to react to obtain a polyamic acid solution;

[0027] (2) coating the polyamic acid solution on a substrate, baking, and curing to obtain the photosensitive polyimide material with a low glass transition temperature.

[0028] Preferably, step (1) is carried out under an inert gas atmosphere.

[0029] Preferably, the inert gas comprises nitrogen.

[0030] Preferably, the stirring speed in step (1) is 100-200 rpm, for example, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The stirring time is 20-40 min, for example, 20 min, 25 min, 30 min, 35 min, 40 min, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0031] Preferably, the cooling in step (1) is cooling to below 5°C, for example 5°C, 3°C, 0°C, -3°C, -5°C, -8°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, preferably -5 to 5°C.

[0032] Preferably, the reaction time of step (1) is 20 to 30 h, for example 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0033] Preferably, the reaction in step (1) is carried out under stirring.

[0034] Preferably, the stirring speed is 150-250rpm, for example 150rpm, 160rpm, 170rpm, 180rpm, 190rpm, 200rpm, 210rpm, 220rpm, 230rpm, 240rpm, 250rpm, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0035] Preferably, the coating in step (2) comprises spin coating.

[0036] Preferably, the spin coating speed is 1400-1600rpm, for example, 1400rpm, 1420rpm, 1440rpm, 1460rpm, 1480rpm, 1500rpm, 1520rpm, 1540rpm, 1560rpm, 1580rpm, 1600rpm, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The spin coating time is 20-40s, for example, 20s, 22s, 24s, 25s, 26s, 28s, 30s, 32s, 34s, 35s, 36s, 38s, 40s, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0037] Preferably, the baking temperature in step (2) is 80-100°C, for example 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The baking time is 8-12min, for example 8min, 9min, 10min, 11min, 12min, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0038] Preferably, the curing temperature in step (2) is 280-320°C, for example 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, 320°C, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range. The curing time is 20-40min, for example 20min, 22min, 24min, 25min, 26min, 28min, 30min, 32min, 34min, 35min, 36min, 38min, 40min, etc., as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0039] Preferably, the curing in step (2) is carried out under an inert gas atmosphere (such as nitrogen, etc.).

[0040] In a third aspect, the present invention provides a use of the photosensitive polyimide material with a low glass transition temperature as described in the first aspect in a temporary bonding material.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention can effectively reduce the glass transition temperature of the polyimide material by introducing functional groups with large free volume into diamine and / or dianhydride, so that the material can soften and bond at a lower temperature, thereby making it a single material that can be used as both a temporary bonding layer and a laser lift-off layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a synthesis mechanism diagram of the polyimide material provided in Example 4 of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] Example 1

[0046] In this embodiment, a photosensitive polyimide material with a low glass transition temperature is provided, and a preparation method thereof comprises the following steps:

[0047] (1) nitrogen was introduced into a 100 mL three-necked flask for 30 min, and then 2.18 g of pyromellitic anhydride and 45 g of N,N-dimethylformamide were added thereto, and the mixture was stirred at a speed of 150 rpm for 30 min until the anhydride was completely dissolved; the solution temperature was lowered to 0° C., and then 3.66 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added, and the mixture was stirred at a speed of 200 rpm for 24 h to obtain a polyamic acid solution;

[0048] (2) The polyamic acid solution obtained in step (1) is spin-coated on glass at a speed of 1500 rpm for 30 seconds, and then baked on a baking plate at 90° C. for 10 minutes, and then cured at 300° C. in a nitrogen atmosphere (oxygen content <100 ppm) for 30 minutes to obtain a polyimide film, that is, the photosensitive polyimide material with a low glass transition temperature is obtained.

[0049] Example 2

[0050] In this embodiment, a photosensitive polyimide material with a low glass transition temperature is provided, and a preparation method thereof comprises the following steps:

[0051] (1) nitrogen was introduced into a 100 mL three-necked flask for 30 min, and then 2.18 g of pyromellitic anhydride and 45 g of N,N-dimethylformamide were added thereto, and the mixture was stirred at 150 rpm for 30 min until the anhydride was completely dissolved; the solution temperature was lowered to 0° C., and then 1.16 g of 1,6-hexanediamine was added, and the mixture was stirred at 200 rpm for 24 h to obtain a polyamic acid solution;

[0052] (2) The polyamic acid solution obtained in step (1) is spin-coated on glass at a speed of 1500 rpm for 30 seconds, and then baked on a baking plate at 90° C. for 10 minutes, and then cured at 300° C. in a nitrogen atmosphere (oxygen content <100 ppm) for 30 minutes to obtain a polyimide film, that is, the photosensitive polyimide material with a low glass transition temperature is obtained.

[0053] Example 3

[0054] In this embodiment, a photosensitive polyimide material with a low glass transition temperature is provided, and a preparation method thereof comprises the following steps:

[0055] (1) nitrogen was introduced into a 100 mL three-necked flask for 30 min, and then 4.44 g of hexafluorodianhydride and 45 g of N,N-dimethylformamide were added thereto, and the mixture was stirred at 150 rpm for 30 min until the dianhydride was completely dissolved; the solution temperature was lowered to 0° C., and then 2.00 g of 4,4′-diaminodiphenyl ether was added, and the mixture was stirred at 200 rpm for 24 h to obtain a polyamic acid solution;

[0056] (2) The polyamic acid solution obtained in step (1) is spin-coated on glass at a speed of 1500 rpm for 30 seconds, and then baked on a baking plate at 90° C. for 10 minutes, and then cured at 300° C. in a nitrogen atmosphere (oxygen content <100 ppm) for 30 minutes to obtain a polyimide film, that is, the photosensitive polyimide material with a low glass transition temperature is obtained.

[0057] Example 4

[0058] In this embodiment, a photosensitive polyimide material with a low glass transition temperature is provided, and a preparation method thereof comprises the following steps:

[0059] (1) nitrogen was introduced into a 100 mL three-necked flask for 30 min, and then 2.18 g of pyromellitic anhydride and 45 g of N,N-dimethylformamide were added thereto, and the mixture was stirred at 150 rpm for 30 min until the anhydride was completely dissolved; the solution temperature was lowered to 0° C., and then 1.00 g of 4,4′-diaminodiphenyl ether and 0.58 g of 1,6-hexanediamine were added, and the mixture was stirred at 200 rpm for 24 h to obtain a polyamic acid solution;

[0060] (2) The polyamic acid solution obtained in step (1) is spin-coated on glass at a speed of 1500 rpm for 30 seconds, and then baked on a baking plate at 90° C. for 10 minutes, and then cured at 300° C. in a nitrogen atmosphere (oxygen content <100 ppm) for 30 minutes to obtain a polyimide film, that is, the photosensitive polyimide material with a low glass transition temperature is obtained.

[0061] The synthesis mechanism diagram of the polyimide material provided in this embodiment is as follows Figure 1 shown.

[0062] Comparative Example 1

[0063] In this comparative example, a photosensitive polyimide material is provided, and the preparation method comprises the following steps:

[0064] (1) nitrogen was introduced into a 100 mL three-necked flask for 30 min, and then 2.18 g of pyromellitic anhydride and 45 g of N,N-dimethylformamide were added thereto, and the mixture was stirred at 150 rpm for 30 min until the anhydride was completely dissolved; the solution temperature was lowered to 0° C., and then 2.00 g of 4,4′-diaminodiphenyl ether was added, and the mixture was stirred at 200 rpm for 24 h to obtain a polyamic acid solution;

[0065] (2) The polyamic acid solution obtained in step (1) is spin-coated on glass at a speed of 1500 rpm for 30 seconds, and then baked on a baking plate at 90° C. for 10 minutes, and then cured at 300° C. in a nitrogen atmosphere (oxygen content <100 ppm) for 30 minutes to obtain a polyimide film, that is, the photosensitive polyimide material.

[0066] The performance test of the polyimide materials provided in the embodiments of the present invention and the comparative examples is carried out as follows:

[0067] (1) Material photosensitivity verification

[0068] The photosensitivity of the polyimide films of the above-mentioned embodiments and comparative examples was evaluated by using a laser with a scanning speed of 3600 mm / s, a spot size of 500 μm, and an irradiation wavelength of 355 nm.

[0069] In the photosensitivity evaluation, a microscope is used to observe the state of the laser traces irradiated on the polyimide film, and the size of the laser traces on the surface of the photosensitive layer (laser indentation diameter / μm) is measured. The laser indentation diameter is evaluated according to the following evaluation criteria:

[0070] ○: The laser indentation diameter is 200 μm or more, which is evaluated as excellent;

[0071] ◎: The laser indentation diameter is between 150 and 200 μm, which is evaluated as good;

[0072] ●: If the diameter of the laser indentation is between 100 and 150 μm, it is rated as fair;

[0073] ×: The laser indentation diameter was less than 100 μm, which was evaluated as poor.

[0074] (2) Glass transition temperature test: measured by differential scanning calorimetry (DSC).

[0075] The performance test results are shown in Table 1.

[0076] Table 1

[0077]

[0078] It can be seen from Table 1 that the polyimide materials provided in the embodiments of the present invention all have a relatively low glass transition temperature (213-273° C., preferably 213-232° C.), and their photosensitivity can meet application requirements, that is, they can meet the requirements of thermal compression bonding and laser debonding.

[0079] Compared with the examples, the dianhydride and diamine in Comparative Example 1 do not have a functional group with a large free volume, and the glass transition temperature of the synthesized polyimide material is greatly increased.

[0080] In summary, compared with monomers with smaller free volumes, the present invention can effectively reduce the glass transition temperature of polyimide by introducing functional groups with large free volumes into diamines and / or dianhydrides.

[0081] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the photosensitive polyimide material with a low glass transition temperature and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A photosensitive polyimide material with a low glass transition temperature, characterized in that: The raw materials for preparing the photosensitive polyimide material with a low glass transition temperature include dianhydride, diamine and solvent; Furthermore, the dianhydride and / or the diamine has a functional group having a large free volume.

2. The photosensitive polyimide material with low glass transition temperature according to claim 1, characterized in that: The functional group with a large free volume includes any one of a -CF3 functional group, a flexible siloxane group, and a flexible long-chain aliphatic hydrocarbon group, or a combination of at least two thereof.

3. The photosensitive polyimide material with low glass transition temperature according to claim 1 or 2, characterized in that: The dianhydride includes any one of 9,9-bis(trifluoromethyl)-2.3.6,7-oxanthene tetracarboxylic dianhydride, hexafluoro dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-oxydiphthalic anhydride, and pyromellitic dianhydride, or a combination of at least two thereof.

4. The photosensitive polyimide material with a low glass transition temperature according to any one of claims 1 to 3, characterized in that: The diamine includes any one of bis(p-aminophenoxy)dimethylsilane, 1,4-bis(aminobutyl)tetramethyldisiloxane, 1,3-bisaminopropyl-1,1,3,3-tetramethyldisiloxane, 2,2'-bis(trifluoromethyl)-4,4'-diaminophenyl ether, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2,2'-bis(trifluoromethyl)-(1,1-diphenyl)-4,4'-diamine, dodecyl diamine, hexamethylene diamine, 1,6-hexanediamine, and 4,4'-diaminodiphenyl ether, or a combination of at least two thereof.

5. The photosensitive polyimide material with low glass transition temperature according to any one of claims 1 to 4, characterized in that: The molar ratio of the dianhydride to the diamine is (0.9-1.1):

1.

6. The photosensitive polyimide material with low glass transition temperature according to any one of claims 1 to 5, characterized in that: The solvent includes any one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, or a combination of at least two thereof; Preferably, based on the total weight of the raw materials for preparing the photosensitive polyimide material with a low glass transition temperature being 100%, the amount of the solvent used is 40% to 95%, preferably 85% to 95%.

7. The photosensitive polyimide material with a low glass transition temperature according to any one of claims 1 to 6, characterized in that: The raw materials for preparing the photosensitive polyimide material with a low glass transition temperature also include auxiliary agents; Preferably, the auxiliary agent includes a leveling agent; Preferably, the leveling agent includes an organic silicon leveling agent and / or a fluorocarbon leveling agent; Preferably, the organosilicon leveling agent includes any one of polydimethylsiloxane, polymethylalkylsiloxane, and organic modified polysiloxane, or a combination of at least two thereof; Preferably, the fluorocarbon leveling agent includes A-3038 and / or FCF-203; Preferably, the glass transition temperature of the photosensitive polyimide material with a low glass transition temperature is below 275°C, preferably 200-250°C.

8. A method for preparing a photosensitive polyimide material with a low glass transition temperature as claimed in any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: (1) mixing dianhydride and a solvent, stirring until the dianhydride is completely dissolved, cooling, and then adding diamine to react to obtain a polyamic acid solution; (2) coating the polyamic acid solution on a substrate, baking, and curing to obtain the photosensitive polyimide material with a low glass transition temperature.

9. The preparation method according to claim 8, characterized in that: Step (1) is carried out under an inert gas atmosphere; Preferably, the inert gas comprises nitrogen; Preferably, the stirring speed in step (1) is 100 to 200 rpm, and the stirring time is 20 to 40 min; Preferably, the cooling in step (1) is to a temperature below 5°C, preferably -5 to 5°C; Preferably, the reaction time in step (1) is 20 to 30 hours; Preferably, the reaction in step (1) is carried out under stirring; Preferably, the stirring speed is 150-250 rpm; Preferably, the coating in step (2) comprises spin coating; Preferably, the spin coating speed is 1400-1600 rpm, and the spin coating time is 20-40 s; Preferably, the baking temperature in step (2) is 80-100° C., and the baking time is 8-12 min; Preferably, the curing temperature in step (2) is 280-320° C., and the curing time is 20-40 min; Preferably, the curing in step (2) is carried out under an inert gas atmosphere.

10. Use of the photosensitive polyimide material with a low glass transition temperature as claimed in any one of claims 1 to 7 in a temporary bonding material.

Images