TWI861655B - Polyimide negative photoresist composition and use thereof - Google Patents

Abstract

A polyimide negative photoresist composition is provided, which comprises: 30 wt% to 90 wt% of a polyimide precursor; 0.1 wt% to 10 wt% of a photo initiator; 1 wt% to 10 wt% of an ester monomer; 0.1 wt% to 3 wt% of a cyclization catalyst represented by the following formula (I); and rest of a solvent,

wherein R₁ is defined in the specification. In addition, a use of the aforesaid polyimide negative photoresist composition is also provided.

Description

Polyimide negative photoresist composition and its use

The present invention relates to a polyimide negative photoresist composition and its use, in particular to a polyimide negative photoresist composition with a specific cyclization catalyst added and its use.

Polyimide (PI) has excellent thermal and mechanical properties and has been widely used in semiconductor packaging processes. Currently commercialized polyimide products are usually supplied in the form of photosensitive resin compositions containing polyimide precursors. In the packaging process, the photosensitive resin composition is coated on the substrate, and then the polyimide precursor molecules are cross-linked and patterned through exposure and development; then, a hardening step is performed through heat treatment, also known as hard baking, to cause the polyimide precursor to undergo a cyclization reaction and form a polyimide hardened film.

In current photosensitive resin compositions, the cyclization reaction temperature of polyimide precursors needs to be 350°C to complete the reaction. However, in the semiconductor packaging process, using high-temperature hard baking to form a polyimide hardened film from a polyimide precursor may cause the polyimide hardened film to shrink and accumulate stress, resulting in warpage of the substrate or degassing and cracking of other materials on the substrate.

In view of this, there is an urgent need to develop a novel photosensitive resin composition containing polyimide precursor to solve the above problems.

The main purpose of the present invention is to provide a polyimide negative photoresist composition, which can carry out the cyclization reaction of the polyimide precursor at low temperature.

The polyimide negative photoresist composition of the present invention includes: 30wt% to 90wt% of polyimide precursor; 0.1wt% to 10wt% of photoinitiator; 1wt% to 10wt% of ester monomer; 0.1wt% to 3wt% of cyclization catalyst represented by the following formula (I); and the remaining amount of solvent;

其中，R₁為C_4-7烷基、-O-COOR₂或-COOR₃，其中R₂為C_1-6烷基，R₃為C_1-6烷基或H。

Wherein, _R1 is _C4-7 alkyl, -O- _COOR2 or _-COOR3 , wherein _R2 is _C1-6 alkyl, _R3 is _C1-6 alkyl or H.

In the composition of the present invention, the added cyclization catalyst represented by formula (I) has a structure of naphthyl imide-trifluoromethanesulfonic acid, and the benzene ring in the structure has a functional group such as an alkyl group, a carbonate group, an ester group or a carbonyl group, and has properties such as high heat stability (high thermal decomposition temperature), good solvent solubility, high photodecomposability, high transparency, good amine resistance (low decomposition rate in the presence of amines), etc. In addition, by adding the cyclization catalyst represented by formula (I), the polyimide negative photoresist composition can be cyclized at a low temperature to solve the problems of substrate warping or degassing or cracking of the material on the substrate caused by the previous high-temperature cyclization reaction. Furthermore, the polyimide hardened film formed by using the polyimide negative photoresist composition of the present invention has good mechanical properties and can be applied to semiconductor devices of different forms of packaging technology, for example, it can be applied to the insulating layer required for the redistribution layer (RDL) in fan-in and fan-out type packaging, and can also be applied to the surface protection layer and back protection layer of the silicon interposer in silicon via technology.

In the composition of the present invention, the amount of the polyimide precursor added may be 30wt% to 90wt%, for example, 30wt% to 85wt%, 30wt% to 80wt%, 30wt% to 75wt%, 30wt% to 70wt%, 30wt% to 65wt%, 30wt% to 60wt%, 30wt% to 55wt%, 30wt% to 50wt%, 30wt% to 45wt% or 30wt% to 40wt%.

In the composition of the present invention, the polyimide precursor can be represented by the following formula (II):

其中，R為

，n為整數。此外，聚醯亞胺前驅物的分子量(Mw)可介於14,000至20,000之間。再者，聚醯亞胺前驅物的聚合物分散性指數(PDI，重量平均分子量/數量平均分子量)可介於1.5至2.4之間。

Among them, R is

, n is an integer. In addition, the molecular weight (Mw) of the polyimide precursor may be between 14,000 and 20,000. Furthermore, the polymer dispersity index (PDI, weight average molecular weight/number average molecular weight) of the polyimide precursor may be between 1.5 and 2.4.

In the composition of the present invention, the amount of the photoinitiator added may be 0.1wt% to 10wt%, for example, 0.1wt% to 9wt%, 0.1wt% to 8wt%, 0.1wt% to 7wt%, 0.1wt% to 6wt%, 0.1wt% to 5wt%, 0.1wt% to 4wt%, 0.5wt% to 4wt%, 0.5wt% to 3wt% or 1wt% to 3wt%.

In the composition of the present invention, the type of photoinitiator is not particularly limited. In one embodiment, the photoinitiator can be shown as the following formula (III):

In the composition of the present invention, the amount of ester monomer added can be 1wt% to 10wt%. By adding an appropriate amount of ester monomer, the negative effect of the composition can be better. In the composition of the present invention, the type of ester monomer is not particularly limited. In one embodiment, the ester monomer can be shown in the following formula (IV):

In the composition of the present invention, the amount of the cyclization catalyst added may be 0.1wt% to 3wt%, for example, 0.5wt% to 3wt%, 0.5wt% to 2.5wt%, 0.5wt% to 2wt% or 1wt% to 2wt%. When the amount of the cyclization catalyst added exceeds 3wt%, poor solubility may occur.

In the composition of the present invention, _R1 of formula (I) may be _C4-7 alkyl, -O- _COOR2 or _-COOR3 , wherein _R2 is _C1-6 alkyl, _R3 is _C1-6 alkyl or H. In one embodiment, _R1 of formula (I) may be _C4-7 alkyl or -O- _COOR2 , wherein _R2 is _C1-6 alkyl. In one embodiment, _R1 of formula (I) may be _C4-7 alkyl, for example, _C4-6 alkyl, _C4-5 alkyl or _C4 alkyl. In one embodiment, _R1 of formula (I) may be -O- _COOR2 , wherein _R2 is _C1-6 alkyl, for example, _C2-6 alkyl, _C3-6 alkyl, _C3-5 alkyl, _C4-5 alkyl or _C4 alkyl.

In one embodiment, the cyclized catalyst can be shown as follows (I-1):

其中，R₁可為C_4-7烷基，例如，可為C_4-6烷基、C_4-5烷基或C₄烷基。

Wherein, R ₁ may be a C _4-7 alkyl group, for example, a C _4-6 alkyl group, a C _4-5 alkyl group or a C ₄ alkyl group.

In one embodiment, the cyclized catalyst can be shown as follows (I-2):

其中，R₁可為-O-COOR₂，其中R₂為C_1-6烷基，例如，可為C_2-6烷基、C_3-6烷基、C_3-5烷基、C_4-5烷基或C₄烷基。

Wherein, R ₁ may be -O-COOR ₂ , wherein R ₂ is a C _1-6 alkyl group, for example, a C _2-6 alkyl group, a C _3-6 alkyl group, a C _3-5 alkyl group, a C _4-5 alkyl group or a C ₄ alkyl group.

In one embodiment, the cyclization catalyst may be a compound represented by the following formula (I-3) or (I-4):

其中，前述化合物可單獨使用或合併使用。

The aforementioned compounds can be used alone or in combination.

The solvent included in the composition of the present invention may be an organic solvent. There is no particular limitation on the type of solvent, as long as the components of the composition (e.g., polyimide precursor) can be completely dissolved therein. Examples of solvents include, but are not limited to, N-methylpyrrolidone (NMP), ethyl lactate (EL), N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, hexamethylphosphatamide, cyclopentanone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethyl lactate, methyl lactate, butyl lactate, tetrahydrofuran or γ-butyrolactone, and the aforementioned solvents may be used alone or in combination of two or more. In one embodiment, the solvent may include N-methylpyrrolidone.

The composition of the present invention may optionally further include 0.1wt% to 10wt% of an adhesion promoter to enhance the negative effect of the composition. The adhesion promoter may be a compound shown in the following formula (V):

In the present invention, the term "alkyl" refers to a linear or branched carbon hydrogen group, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl and tert-butyl.

In addition, unless otherwise specified, the alkyl group in the compound includes substituted or unsubstituted groups. Possible substituents include, but are not limited to, alkyl, cycloalkyl, halogen, alkoxy, alkenyl, heterocycloalkyl, aryl, heteroaryl, amino, carboxyl or hydroxyl, but the alkyl group will not be substituted by an alkyl group.

The present invention further provides the use of the aforementioned polyimide negative photoresist composition for use in a low-temperature curing process, wherein the low temperature refers to below 250°C. In one embodiment, the temperature of the low-temperature curing may be between 150°C and 250°C, for example, between 150°C and 200°C. In one embodiment, the temperature of the low-temperature curing may be about 170°C.

The present invention further provides a method for forming a patterned hardened film using the aforementioned polyimide negative photoresist composition, comprising: applying the aforementioned polyimide negative photoresist composition on a substrate to form a film layer; performing exposure and development to pattern the film layer; and heat-treating the patterned film layer to form a patterned polyimide hardened film. The temperature of the heat treatment may be below 250°C, for example, between 150°C and 250°C or between 150°C and 200°C.

The present invention further provides a semiconductor device, which includes: a polyimide cured film formed using the aforementioned polyimide negative photoresist composition.

The following is a specific embodiment to illustrate the implementation of the present disclosure. People familiar with this art can easily understand the other advantages and effects of the present disclosure from the content disclosed in this manual. The present disclosure can also be implemented or applied through other different specific embodiments. The details in this manual can also be modified and changed in various ways according to different viewpoints and applications without deviating from the spirit of this creation.

Unless otherwise specified in the text, the singular forms "a", "an" and "the" used in the specification and the attached patent claims include one or more individuals.

Unless otherwise specified in the text, the term "or" used in the specification and the attached patent application generally includes the meaning of "and/or".

In addition, in this article, the term "about" generally means within 20%, 10%, 5%, 3%, 2%, 1%, or 0.5% of a given value or range. The quantity given here is an approximate quantity, that is, in the absence of a specific description of "about", the meaning of "about" can still be implied. In addition, the term "range is from a first value to a second value" or "range is between a first value and a second value" means that the range includes the first value, the second value, and other values between them.

The present disclosure will be more specifically described by way of examples, but such examples are not intended to limit the scope of the present disclosure. Unless otherwise specified, in the following preparation examples, examples and comparative examples, the temperature is in degrees Celsius, and the parts and percentages are by weight. The relationship between weight parts and volume parts is the same as the relationship between kilograms and liters.

Preparation of polyimide precursor

Add 151g of ODPA (4,4'-Oxydiphthalic anhydride) to a 2L split-type pellet-bottomed reaction bottle, then add 427g of NMP (1-Methyl-2-pyrrolidinone) and stir evenly, then add 131g of HEMA (2-Hydroxyethyl methacrylate) and 0.8g of MEHQ (4-Methoxyphenol), then add 98g of pyridine, raise the temperature to 60°C, and stir for 18 hours.

The reaction solution was cooled in an ice bath, and 165 g of DCC (N,N'-dicyclohexylcarbodiimide) was added to 237 g of NMP to dissolve. Then, 80 g of ODA (4,4-oxydianiline) was added. After the addition of ODA, the reaction was allowed to proceed at room temperature for 2 hours.

Add 30g of ethanol and react for 1 hour, then add 400g of NMP and filter. Put the filtrate into ethanol to precipitate the precipitate, filter to obtain the precipitate, then wash the precipitate with a large amount of deionized water, and dry the precipitate in a vacuum oven. The dried precipitate is the polyimide precursor.

Here, the obtained polyimide precursor is as shown in formula (II), the molecular weight (Mw) is about 14000 to 20000, and the polymer dispersity index (PDI) is about 1.5 to 2.4.

Polyimide negative photoresist composition

According to the composition formula shown in Table 1 below, the polyimide negative photoresist composition of Examples 1 to 5 and Comparative Examples 1 to 3 is prepared, wherein the preparation method is roughly as described below.

The polyimide precursor, photoinitiator, cyclization catalyst, adhesion promoter, ester monomer and solvent were prepared into the polyimide negative photoresist compositions of Examples 1 to 5 and Comparative Examples 1 to 3 according to the composition formula shown in Table 1 below. The polyimide precursor used is the polyimide precursor prepared above; the photoinitiator used is shown in formula (III) (CAS No: 2097490-25-8); the cyclization catalyst used in Example 1 is shown in formula (I-3) (CAS No: 1610827-31-0), the cyclization catalyst used in Examples 2 to 5 and Comparative Example 1 is shown in formula (I-4) (CAS No: 2668228-65-5), and the cyclization catalyst used in Comparative Example 3 is shown in formula (I'); the adhesion promoter used is shown in formula (V) (CAS No: 38280-61-4); the ester monomer used is shown in formula (IV) (CAS No: 109-17-1); and the solvent used is NMP.

Test case

First, prepare a substrate, which is a 6-inch silicon wafer, and clean the substrate surface with deionized water and acetone. Then, evenly apply the polyimide negative photoresist composition prepared in Examples 1 to 5 and Comparative Examples 1 to 3 on the substrate by spin coating. Then, soft bake at 100°C for 4 minutes, and then use an exposure machine to expose the polyimide negative photoresist composition applied on the substrate surface. Then, spray cyclopentanone at 23°C for 15 seconds. Perform at 150°C for 30 minutes; then, perform hard baking at 170°C for 2 hours. Finally, the substrate and the cured film were cooled to room temperature to obtain the desired sample, and the sample thickness was 8μm.

The obtained samples were tested for mechanical properties using a tensile machine, and the test results are shown in Table 1. Regarding elongation, "◎" indicates an elongation of more than 60%, "○" indicates an elongation between 40% and 60%, and "X" indicates an elongation of less than 40%. Regarding tensile strength, "◎" indicates a tensile strength of more than 130MPa, "○" indicates a tensile strength between 120MPa and 130MPa, and "X" indicates a tensile strength of less than 120MPa.

Table 1

As shown in the results of Table 1 above, compared with Comparative Example 2 in which no cyclization catalyst is added, the polyimide negative photoresist compositions of Examples 1 to 5 in which Formula (I-3) and Formula (I-4) are added have good mechanical properties. Compared with Comparative Example 3 in which a cyclization catalyst of Formula (I') is added (without a functional group at the benzene ring), the polyimide negative photoresist compositions of Examples 1 to 5 can improve the solubility of the components in the composition due to the addition of a cyclization catalyst having a functional group at the benzene ring. In addition, the polyimide negative photoresist compositions of Examples 1 to 5 with appropriate amounts of cyclization catalyst added have good solubility, but the polyimide negative photoresist composition of Comparative Example 1 with a cyclization catalyst content of 5wt% has a problem of poor solubility.

In summary, the polyimide negative photoresist composition of the present invention can make the polyimide negative photoresist composition have good solubility by adding an appropriate amount of a cyclization catalyst having a functional group at the benzene ring, and the obtained polyimide has good mechanical properties (elongation is more than 40%, and tensile strength is more than 130MPa). In addition, the polyimide negative photoresist composition of the present invention can make the polyimide precursor undergo cyclization reaction at low temperature by adding an appropriate amount of a cyclization catalyst having a functional group at the benzene ring, so as to avoid the problems such as substrate warping or degassing or cracking of the material on the substrate caused by high-temperature cyclization reaction.

The above embodiments are merely examples for the convenience of explanation. The scope of rights claimed by this disclosure shall be subject to the scope of the patent application, and shall not be limited to the above embodiments.

Claims (8)

A polyimide negative photoresist composition comprises: 30 wt % to 90 wt % of a polyimide precursor; 0.1 wt % to 10 wt % of a photoinitiator; 1 wt % to 10 wt % of an ester monomer; 0.1 wt % to 3 wt % of a cyclization catalyst represented by the following formula (I); and the remainder of a solvent;

Wherein, R ₁ is C _4-7 alkyl, -O-COOR ₂ or -COOR ₃ , wherein R ₂ is C _1-6 alkyl, R ₃ is C _1-6 alkyl or H; wherein the polyimide precursor is represented by the following formula (II):

Among them, R is

, n is an integer; wherein the ester monomer is represented by the following formula (IV):

The polyimide negative photoresist composition as described in claim 1, wherein the molecular weight of the polyimide precursor is between 14,000 and 20,000. The polyimide negative photoresist composition as described in claim 1, wherein the photoinitiator is represented by the following formula (III):

The polyimide negative photoresist composition as described in claim 1, wherein formula (I) is as shown in formula (I-1):

Wherein, R ₁ is a C _4-7 alkyl group. The polyimide negative photoresist composition as described in claim 1, wherein formula (I) is as shown in formula (I-2):

Wherein, R ₁ is -O-COOR ₂ , and R ₂ is C _1-6 alkyl. The polyimide negative photoresist composition as described in claim 1, wherein the cyclization catalyst is represented by the following formula (I-3) or (I-4):

The polyimide negative photoresist composition as described in claim 1 further includes: 0.1wt% to 10wt% of an adhesion promoter. A use of a polyimide negative photoresist composition as described in any one of claims 1 to 7, for use in a low-temperature curing process, wherein low temperature refers to below 250°C.