JP2002299505A - Manufacturing method of semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting method using a polyimide film which is suitable for bonding a mounting substrate and a semiconductor element, and excellent in heat resistance, with no adhesion degraded even under a high temperature. SOLUTION: There are provided a process to prepare a semiconductor wafer 1 where a bump or post is provided on a pad, a process where a silicon denatured polyimide film containing crosslink radical or its precursor film is laminated on a post formation surface side or a bump 3 of the semiconductor wafer at 50-200 deg.C to form an adhesive layer 6 while a semiconductor wafer in which a tip of the bump or post is exposed is formed, and a process to dice the semiconductor wafer thereafter to provide a semiconductor element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device having a semiconductor device provided with an adhesive layer such as a polyimide film.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and higher in density, higher integration of semiconductor elements has been progressing. Accordingly, various semiconductor package forms have been proposed. For example, as an insulating substrate of the package, an organic package substrate of an epoxy resin type or a polyimide resin type,
An inorganic substrate such as silicon is used, and a metal plate for heat dissipation is also used. Therefore, the bonding of these various kinds of different materials is an important elemental technology that affects the reliability of the entire package.

Conventionally, when mounting a semiconductor element on a substrate, a liquid adhesive has been used. Specifically, the pad provided on the substrate and the semiconductor element with a bump are connected to each other by cream solder or the like between the substrate pad and the bump, and then, from the part where the bump on the integrated circuit of the semiconductor element is not formed. A method of injecting a liquid resin composed of a filled epoxy resin and fixing the resin by heat has been adopted. However, when a liquid resin is used, air may be mixed into the resin at the time of injecting the resin and bubbles may be formed at the time of fixing the resin, and it is difficult to inject a predetermined amount of the resin, There were problems such as leakage.

Therefore, a method of using a film adhesive without using a liquid material is disclosed in Japanese Patent Application Laid-Open No. Hei 8-236578. According to this method, since the substrate and the semiconductor element are pressure-bonded with the viscous solid adhesive, the mounting process can be simplified because the connection between the substrate pad and the bump does not require a temporary connection by solder. Are listed as advantages. However, the film adhesive described in this publication is also based on an epoxy resin, and its properties are not satisfactory in terms of heat resistance, adhesiveness at high temperatures, and the like.

In the process of manufacturing a package using a film adhesive, an adhesive is often formed in advance on the surface of a substrate to be adhered on one side in order to improve workability. Since the agent goes through a substrate processing step and the like, it is required that the characteristics do not change when subjected to heat or chemical treatment. In addition, since the adhesive used around these semiconductors also undergoes a reflow process and the like, it is important that the adhesive strength at a high temperature is not reduced and that volatile components that cause circuit contamination are small.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a semiconductor device which has good heat resistance and good adhesion at high temperatures, and which enables connection between a semiconductor element and a mounting substrate without going through a complicated mounting process. An object of the present invention is to provide a device manufacturing method.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have used a polyimide film for the adhesive layer used in the mounting process and further devised a manufacturing method. It was found that the above-mentioned problems were solved, and the present invention was completed.

That is, the present invention provides a step of preparing a semiconductor wafer having a plurality of pads and a passivation film and having bumps or posts provided on each of the pads, and providing a polyimide on the bump or post formation surface side of the semiconductor wafer. 40-200 ° C for precursor film or polyimide film
Forming an adhesive layer by laminating in the range, a step of forming a wafer in which the tips of the bumps or posts are exposed from the surface of the adhesive layer, and then dicing the wafer into a semiconductor element, It is a manufacturing method. Here, the adhesive layer formed from the polyimide precursor film or the polyimide film preferably has the following characteristics. Glass transition temperature 50-250 ° C, 250 ° C
Young's modulus (storage elastic modulus) is 10 ⁵ Pa or more, and the peel strength of thermocompression-bonded copper foil is 0.7 kN / m.
that's all. In the method for manufacturing a semiconductor device, it is preferable that the polyimide precursor film or the polyimide film has a thickness of 50 to 150% with respect to the height of the bump or the post.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. In the following description, individual elements constituting a semiconductor wafer before dicing may also be referred to as semiconductor elements. FIG. 1 shows pad 2,
1 shows an example of a semiconductor element 1 provided with a bump 3 and a passivation film 4. As shown in FIG.
The semiconductor element 1 has a plurality of pads 2 and a passivation film 4. The pads 2 are used to connect to circuit elements of a semiconductor element, and each pad enables electrical connection to the outside via bumps 3 or posts (not shown) provided thereon. It is. The bumps 3 are for electrical connection with pads on the mounting board, and the posts mainly serve the same function. The passivation film 4 is provided for protecting the circuit 5 on the semiconductor element. Such a semiconductor element 1 is known and can be manufactured by a known method.

FIG. 2 shows a polyimide precursor film or a polyimide film (hereinafter also referred to as an adhesive film) on the bump or post forming surface side of the semiconductor element 1 shown in FIG.
Are laminated to form the adhesive layer 6. The adhesive layer 6 laminated on the semiconductor element 1 has a function of adhering the semiconductor element 1 and a mounting substrate on which the semiconductor element 1 is to be mounted later, and has a feature that the adhesive property is hardly reduced even when subjected to a heat treatment at 270 ° C. or lower. Have.

The lamination is preferably performed under heat and pressure. The laminating temperature needs to be 50 to 200 ° C, preferably 100 to 160 ° C.
If the laminating temperature is lower than 50 ° C., the adhesive strength to the semiconductor element is low, and if the laminating temperature is higher than 200 ° C., foaming due to the residual solvent may occur. During lamination, it is desirable to apply pressure in the range of 0.1 to 2 MPa, more preferably in the range of 0.1 to 0.5 MPa. The pressing time during lamination is preferably in the range of 0.5 to 3 minutes.

The adhesive film used in the present invention is used after being laminated on a semiconductor element (wafer). The adhesive layer formed from the adhesive film on the semiconductor element is
It is preferable that the glass transition temperature, the Young's modulus (storage modulus) at 250 ° C., and the peel strength between the copper foil and the copper foil when thermocompression-bonded have the above characteristics. If the above characteristics are not satisfied, it will not be sufficiently suitable as an adhesive layer when the semiconductor element 1 is mounted on the mounting substrate 7.

The glass transition temperature of the adhesive layer is 40 to 40.
It is preferably in the range of 250 ° C.,
C. is more preferred. Here, the glass transition temperature refers to one measured by a DMA method described later.
When the glass transition temperature is less than 40 ° C., the mechanical strength of the film around room temperature is significantly reduced, and when the glass transition temperature exceeds 250 ° C., a very high thermocompression bonding temperature is required for sufficient adhesion, Damage to peripheral materials and the polyimide resin itself increases.

Further, Young's modulus (storage modulus) of the adhesive layer
Is measured by the DMA method and at a temperature of 250 ° C., 1
0^FivePa or higher, preferably 10⁶-10⁹Pa's
More preferably, the range is 10⁶-10⁸Pa range is best
Good. This Young's modulus is 10 ^FiveIf it is less than Pa, infrared
Adhesive peeled off when mounting the package in a reflow furnace, etc.
And foaming may occur. Furthermore, the adhesive layer is copper foil
Peel strength against the copper foil when thermocompression-bonded to
7 kN / m or more, preferably 0.9 kN / m or more
More preferably, it is above. The value of this peel strength is 0.
If less than 7 kN / m, the semiconductor device will
It is not preferable because it is easily peeled off. In addition, glass
Detailed measurement methods of transfer temperature, Young's modulus and peel strength
Measured based on the method described in the test method in the examples below
can do. The adhesive film is laminated
Depending on the conditions, there is a possibility of metamorphosis.
Under mining conditions, the likelihood or degree of metamorphosis is minimal
Therefore, the above characteristics under the above measurement conditions of the adhesive layer
Can also be referred to as characteristics of an adhesive film.

The thickness of the adhesive film serving as the adhesive layer is 50 to 150% of the height of the bump or post on the semiconductor element.
Is preferably within the range. If the thickness of the polyimide film is less than 50% of the height of the bump or the post, the adhesion to the mounting board cannot be performed well, which is not preferable.
If it exceeds 50%, the connection between the bump or post and the pad on the mounting board may be defective.

The polyimide precursor or polyimide serving as the adhesive film of the present invention is obtained from an aromatic tetracarboxylic dianhydride (A) and a diamine (B). The aromatic tetracarboxylic dianhydride (A) is not particularly limited, but includes the following compounds. Pyromellitic dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic dianhydride, 2,2', 3,3'-benzophenonetetracarboxylic dianhydride, 2,3,3 ', 4'-benzophenonetetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2 , 4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic dianhydride,
Naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-
Dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,
6-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,
6,7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,7-dichloro Naphthalene-1,4,5,8
-Tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 1,4,5,8
-Tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride, 2,2', 3,3'-biphenyltetra Carboxylic dianhydride,
2,3,3 ', 4'-biphenyltetracarboxylic dianhydride, 3,
3 '', 4,4 ''-p-terphenyltetracarboxylic dianhydride,
2,2 '', 3,3 ''-p-terphenyltetracarboxylic dianhydride, 2,3,3 '', 4 ''-p-terphenyltetracarboxylic dianhydride, 2,2- Bis (2,3-dicarboxyphenyl) -propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride , Bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3.4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride, bis (3,4- Dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane dianhydride, perylene-2 3,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene
-4,5,10,11-tetracarboxylic dianhydride, perylene-5,6,
11,12-tetracarboxylic dianhydride, phenanthrene-1,
2,7,8-tetracarboxylic dianhydride, phenanthrene-1,
2,6,7-tetracarboxylic dianhydride, phenanthrene-1,
2,9,10-tetracarboxylic dianhydride, cyclopentane-1,
2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5,6-
Tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride object.
These can be used alone or in combination of two or more. Among these, pyromellitic dianhydride, 4,
When 4'-oxydiphthalic dianhydride or 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride is used as a polyimide resin, solubility in organic solvents and adhesion to adherends such as copper surface It is suitable because it is excellent in such as.

The diamine (B) is not particularly limited, but preferably contains a diamine (B1) having a crosslinkable reactive group. Diamine having a crosslinkable reactive group (B
Although 1) is not limited as long as it is a diamine having a crosslinkable reactive group, a diamine component having at least one type of crosslinkable reactive group selected from a phenolic hydroxyl group, a carboxyl group, and a vinyl group as the crosslinkable reactive group. Is preferred. These cross-linking groups react with the amino group, acid anhydride group or carboxyl group at the end of the polyimide at the time of high-temperature thermocompression bonding, thereby increasing the elastic modulus at high temperatures and improving the reflow heat resistance. is there. Since this cross-linking reaction proceeds remarkably at 270 ° C. or higher, 27 ° C.
Even when a heat history up to 0 ° C. is received, the processing fluidity can be maintained.

Preferred specific examples of the diamine (B1) having a crosslinkable reactive group include 3,3'-dihydroxy-4,4'-
Diaminobiphenyl, 3,5-diaminobenzoic acid, 1,8-diamino-4,5-hydroxyanthraquinone, 2,4-diamino-6-
Hydroxypyrimidine, 2,3-diaminophenol, ω,
ω'-bis (3-aminopropyl) polymethylvinylsiloxane and the like. A preferred ratio of the diamine (B1) having a crosslinkable reactive group is 5 to 5% of the total diamine (B).
９５95 mol%. In particular, when having a phenolic hydroxyl group or a carboxyl group as a crosslinking reactive group,
The use ratio of (B1) in the total diamine (B) is 5 to 5.
A range of 30 mol% is preferred. When this ratio is 5 mol% or less, the heat resistance is low, and when this ratio is 30 mol% or more, the improvement in heat resistance in proportion to the added amount is not observed. Further, when a vinyl group is used as a crosslinkable reactive group, 20
-100 mol% is preferable, and when it is 20 mol% or less, the heat resistance is low.

It is also advantageous to include a siloxane diamine (B2) in the diamine (B). The siloxane diamine (B2) is preferably a siloxane diamine represented by the following general formula (1).

Embedded image In the general formula (1), R ₁ and R _{2 each} independently represent a divalent hydrocarbon group, and preferably include a polymethylene group or a phenylene group having 2 to 6, more preferably 3 to 5 carbon atoms.
R _{3 to} R _{6 each} independently represent a hydrocarbon group having 1 to 6 carbon atoms, and preferably include a methyl group, an ethyl group, a propyl group, or a phenyl group. N is an average repeating unit, and is 1 to 1
It represents the number 0, preferably the number 3-9.

Examples of specific compounds of the siloxane diamine (B2) include ω, ω'-bis (2-aminoethyl) polydimethylsiloxane, ω, ω'-bis (3-aminopropyl) polydimethylsiloxane, ω , Ω'-bis (4-aminophenyl) polydimethylsiloxane, ω, ω'-bis (3-aminopropyl) polydiphenylsiloxane, ω, ω'-bis (3-aminopropyl) polymethylphenylsiloxane, etc. Can be The preferable usage ratio of the siloxane diamine (B2) is in the range of 5 to 95 mol% of the total diamine (B). When this ratio is 5 mol% or less, the adhesiveness is low, and when it is 95 mol% or more, the ratio of the diamine having a crosslinkable reactive group is reduced, and the heat resistance is low.

Diamine components (B3) other than the components (B1) and (B2) can also be used. Although not particularly limited, the following aromatic diamines may be mentioned. For example,
3,3'-dimethyl-4,4'-diaminobiphenyl, 4,6-dimethyl-m-phenylenediamine, 2,5-dimethyl-p-phenylenediamine, 2,4-diaminomesitylene, 4,4'-methylenedi -
o-Toluidine, 4,4'-methylenedi-2,6-xylidine, 4,4 '
-Methylene-2,6-diethylaniline, 2,4-toluenediamine, m-phenylene-diamine, p-phenylene-diamine,
4,4'-diamino-diphenylpropane, 3,3'-diamino-diphenylpropane, 4,4'-diamino-diphenylethane,
3,3'-diamino-diphenylethane, 4,4'-diamino-diphenylmethane, 3,3'-diamino-diphenylmethane, 2,2-
Bis [4- (4-aminophenoxy) phenyl] propane 4,4'-
Diamino-diphenyl sulfide, 3,3'-diamino-diphenyl sulfide, 4,4'-diamino-diphenyl sulfone, 3,3'-diamino-diphenyl sulfone, 4,4'-diamino-diphenyl ether, 3,3-diamino- Diphenyl ether, benzidine, 3,3'-diamino-biphenyl, 3,3'-
Dimethyl-4,4'-diamino-biphenyl, 3,3'-dimethoxy
-Benzidine, 4,4'-diamino-p-terphenyl, 3,3'-diamino-p-terphenyl, bis (p-amino-cyclohexyl) methane, bis (p-β-amino-t-butylphenyl) Ether, bis (p-β-methyl-δ-aminopentyl) benzene, p-bis (2-methyl-4-amino-pentyl) benzene, p-
Bis (1,1-dimethyl-5-amino-pentyl) benzene, 1,5-
Diamino-naphthalene, 2,6-diamino-naphthalene, 2,4-
Bis (β-amino-t-butyl) toluene, 2,4-diamino-toluene, m-xylene-2,5-diamine, p-xylene-2,5-diamine, m-xylylene-diamine, p-xylylene- Diamine, 2,6-diamino-pyridine, 2,5-diamino-pyridine,
2,5-diamino-1,3,4-oxadiazole, piperazine,
1,3-bis (3-aminophenoxy) benzene and the like. These can be used alone or in combination of two or more. Among these, 2,2-bis [4- (4-aminophenoxy) phenyl] propane is preferable because it has excellent solubility in organic solvents and the like, and is easily used in the reaction. When the diamine component (B3) is used, a preferable use ratio thereof is in the range of 0 to 80 mol% in the total diamine (B).
When this proportion is 80 mol% or more, the fraction of the diamine having a crosslinkable reactive group decreases, and the heat resistance becomes low.

Diamine (B) occupying in diamine (B)
1), (B2) and (B3) can be summarized as (B
1) 5 to 95 mol%, preferably 5 to 30 mol%, more preferably 10 to 20 mol%, (B2) 5 to 95 mol%, preferably 10 to 70 mol%, more preferably 30
-60 mol%, (B3) 0-80 mol%, preferably 1
It is 0 to 70 mol%, more preferably 20 to 50 mol%. The diamine (B) is the same as the diamine (B1), (B
2) and (B3), which are used in approximately equimolar amounts with the aromatic tetracarboxylic dianhydride (A).

The method for producing the polyimide or the precursor is not particularly limited, and a known polymerization method can be used. Preferably, the reaction is carried out in two or more steps by reacting the siloxane diamine (B2) with the aromatic tetracarboxylic dianhydride (A) until imidization, and then reacting the diamine (B1) having a crosslinkable reactive group with the aromatic tetracarboxylic acid. The carboxylic dianhydride (A) is reacted until a polyamic acid is formed. When another diamine (B3) is used, it is preferable to carry out the reaction so as to generate a polyamic acid as in the reaction between the diamine (B1) having a crosslinkable reactive group and the aromatic tetracarboxylic dianhydride (A). By adopting such a polymerization method, an imidized portion,
Thus, a copolymerized siloxane polyimide resin precursor remaining in the amic acid stage, which is a precursor of the imide, is obtained.

When a polyimide precursor resin formed from a diamine (B1) having a crosslinkable reactive group and an aromatic tetracarboxylic dianhydride (A) is subjected to a heat treatment at 150 ° C. or more in a solution, the polyimide is easily crosslinked in the solution. The reaction proceeds, and the subsequent processability becomes difficult. Further, the polyimide precursor resin formed from siloxane diamine (B2) and aromatic tetracarboxylic dianhydride has higher hydrolyzability and lower storage stability in solution than the aromatic polyimide precursor resin. Therefore, the amic acid site is preferably imidized in advance.

The following are the preferred polymerization methods. Aromatic tetracarboxylic dianhydride (A)
Is dissolved or suspended in an organic solvent, and siloxane diamine (B2) is gradually added. Thereafter, the mixture is heated at a temperature of 150-210 ° C. while removing condensed water for 1 hour.
Polymerization and imidization are performed for 0 to 24 hours to obtain a siloxane polyimide having an acid anhydride at a terminal. Next, once the reaction mixture is cooled to around room temperature, the diamine (B1) having a crosslinkable reactive group is essential so that the acid anhydride (A) and the total diamine (B) are substantially equimolar. A diamine mixture selected from aromatic diamines and other diamines (B3) is added and reacted at 10 to 80 ° C. for 1 to 3 hours to obtain a siloxane polyimide precursor resin solution having a crosslinkable reactive group.

The organic solvent used in the reaction is not particularly limited, but may be a single solvent or a mixture of two or more solvents as long as the composition can be uniformly dissolved. . For example, phenol solvents, amide solvents (pyrrolidone solvents, acetamide solvents, etc.), oxane solvents (dioxane, trioxane, etc.), ketone solvents (cyclohexanone, etc.), glyme solvents (methyldiglyme, methyltriglyme, etc.) )and so on. If necessary, an aromatic hydrocarbon-based solvent such as benzene or toluene or an aliphatic hydrocarbon-based solvent such as hexane or decane can be mixed and used as far as it can be uniformly dissolved. Due to the problem of shortening the reaction time and dissipating the solvent, those with a boiling point of 150 ° C or higher are preferred
Most preferred are organic polar solvents (e.g., N-methyl-2-pyrrolidinone, methyltriglyme, etc.) having a temperature of at least 0C.

The molecular weight of the siloxane polyimide precursor resin solution can be controlled by adjusting the molar ratio of the monomer components as in the case of the ordinary polycondensation polymer. That is, it is preferable to use 0.8 to 1.2 moles of the diamine (B) with respect to 1 mole of the aromatic tetracarboxylic dianhydride (A). When the molar ratio is 0.8 or less and 1.2 or more, only low molecular weight ones can be obtained, and sufficient heat resistance cannot be obtained. More preferably, the amount of the diamine (B) is 0.95 to 1.05 mol, particularly preferably 0.98 to 1.02 mol, per 1 mol of the aromatic tetracarboxylic dianhydride (A).

As a component that can be blended with the polyimide resin or the precursor, for example, an appropriate amount of a thermosetting resin such as an epoxy resin, an acrylate resin, a urethane resin, and a cyanate resin is used for the purpose of improving the moldability in the heat compression bonding step. It can also be added. These thermosetting resins improve the fluidity during high-temperature bonding, and have the effect of improving heat resistance after curing by crosslinking between the functional groups in the polyimide structure during high-temperature bonding or post-baking. is there. In addition, at the time of its production, in addition to the above components in any step, a conventionally known coupling agent, a filler, a pigment, a thixotropic agent, an antifoaming agent, and the like are appropriately blended as necessary. Is also good. These are preferably those which do not decompose or volatilize at a temperature of about 300 ° C.

The polyimide precursor or polyimide is formed into a solution to form a polyimide precursor film or polyimide film, that is, an adhesive film. The method for obtaining the adhesive film is not particularly limited, but a solution containing a polyimide or a precursor and components to be blended as necessary is applied to a sheet-like material, and the solution is applied at 300 ° C or lower, preferably 180 to It is preferable to heat to 270 ° C. for several minutes for imidization. However, in order to maintain adhesion,
It is preferable that the cross-linking reaction by the cross-linkable reactive group is not sufficiently advanced. Advantageously, the siloxane polyimide precursor resin-containing solution obtained in this manner is applied to an arbitrary substrate, and preliminarily dried at a temperature of 130 ° C. or lower for 10 to 30 minutes, and then the solvent is removed and the imidization is performed. Usually 180 for
Heat treatment is performed at a temperature of about 270 ° C. for about 2 to 30 minutes.
Here, as the supporting base material, PET subjected to release treatment is used.
Films are preferred. The polyimide resin usually starts to crosslink at a temperature equal to or higher than its glass transition temperature, but unless a sufficient temperature and time are given, the crosslinking reaction by the crosslinkable reactive group is not completed.

The thickness of the adhesive film obtained by the heat treatment is adjusted according to the height of the bumps and the like, but is preferably in the form of a film having a thickness of usually 10 to 100 μm.
That is, the thickness of the adhesive film is in the range of 50 to 150% with respect to the height of the bump or post, and further,
Those having a range of 80 to 120% are preferred. Note that 180
After the heat treatment at ２270 ° C., the imidization is substantially completed, but the heat treatment should be performed at a temperature of about 270 ° C. for about 5 minutes for more complete imidization and removal of low molecular weight components. Is preferred. The imidization ratio of the adhesive layer before mounting on the mounting board is preferably 95% or more. The imidation ratio can be measured by infrared absorption spectrum analysis. Here, the imidation ratio is a value before the semiconductor element is thermocompression-bonded to the mounting substrate, that is, a wafer obtained by dicing the wafer into individual semiconductor elements with an adhesive layer.

FIGS. 3 and 4 show a step of exposing the tip of the bump 3 or the post from the surface of the adhesive layer 6 laminated on the bump forming surface side of the semiconductor element 1. FIG. This step is optional, and is necessary when the thickness of the polyimide film is thicker than the bump or post or when resin residue remains on the top of the bump tip. The method of exposing the tip of the bump or the post from the surface of the adhesive layer 6 is not particularly limited, but the adhesive layer 6 formed after lamination and covering at least the bump or the post may be used. It can be removed by a plasma treatment, a laser treatment, or an alkaline solution treatment to expose the tips of the bumps or posts.

FIG. 3 shows a state in which the thickness of the adhesive layer 6 and the height of the bump 3 are substantially equal, but a part of the adhesive film laminated on the bump tip, that is, the residue of the adhesive layer remains on the bump tip. Things. In this case, only the residue portion is removed by plasma treatment, laser treatment or alkali solution treatment, so that the tip of the bump or post can be exposed as shown in FIG. When the thickness of the adhesive layer 6 is considerably larger than the height of the bump 3 or the post, the bump 3 is buried under the adhesive layer 6. By removing a desired thickness range of the surface by plasma treatment, laser treatment or alkali solution treatment, the tip of the bump or post can be exposed as shown in FIG.

The semiconductor element having the adhesive layer 6 formed by lamination is preferably subjected to a heat treatment at a temperature of at least 270 ° C. for at least 5 minutes before being mounted on a mounting substrate. By performing the heat treatment in this manner, characteristics as a polyimide, that is, thermal stability at high temperatures such as heat resistance are exhibited. In addition, the adhesive film used in the present invention has enough adhesive force to stably adhere the semiconductor element 1 and the mounting substrate even after the heat treatment.

FIG. 5 shows that the semiconductor wafer having the adhesive layer 6 and at least a part of the upper surface of the bump or the post is exposed is diced into a predetermined unit by a diamond blade or the like to obtain a unit semiconductor element 11. 2 shows a process of mounting the semiconductor device 1 on the pads 8 on the mounting substrate face down so that the surface on which the adhesive layer is formed and the mounting substrate 7 are in contact with each other. The mounting substrate 7 used here is not particularly limited, and examples thereof include those made of glass epoxy resin, those made of polyimide resin, and the like, such as adhesion to a polyimide film, affinity, and coefficient of linear expansion. A substrate made of the same kind of polyimide resin is preferable from the viewpoint of the dimensional change rate of the resin.

[0035]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Synthesis Example 1 In a Dean-Stark type reactor equipped with a stirrer and a nitrogen inlet tube, 3,3 ′, 4,4′-oxydiphthalic dianhydride 69.80.
g (0.225 mol) and 130 g of triglyme were charged and ω, ω′-bis (3-aminopropyl) polydimethylsiloxane (PSX: average number of siloxane units n = 7.98, average molecular weight 766) under a nitrogen atmosphere. 01
g (0.1175 mol) using a dropping funnel,
Stirred at room temperature for about 2 hours. Subsequently, the reaction solution was heated to 190 ° C. under a nitrogen atmosphere, and heated and stirred for 15 hours while removing condensed water. Next, the reaction solution was cooled to room temperature, and 36.54 g (0.089 mol) of 2,2-bis [4- (4-aminophenoxy) phenyl] propane and 3,3
3.89 g of 3'-dihydroxy-4,4'-diaminobiphenyl
(0.018 mol) and 150 g of triglyme,
This reaction solution was heated to 70 ° C. under a nitrogen atmosphere and stirred for about 2 hours, and triglyme was further added so as to have a solid concentration of 40 parts by weight to obtain a polyimide precursor resin solution.

Characteristic Test of Polyimide Film [Preparation of Resin Film] The polyimide precursor resin solution obtained in Synthesis Example 1 was subjected to a silicone release treated PET substrate (thickness: 50 μm).
After pre-drying at 120 ° C. for 6 minutes in a hot air oven, heat treatment is performed in the order of 180 ° C. for 5 minutes and 270 ° C. for 5 minutes to obtain a resin film A with a PET base material having a resin film thickness of about 30 μm.
I got The resin film A was peeled off and immersed in N-methyl-2-pyrrolidinone (abbreviated as NMP) at 25 ° C. for 10 minutes,
When the state of NMP solubility was visually observed, it was confirmed that it was insoluble.

[Glass Transition Temperature, Young's Modulus] The resin film A after the above-mentioned peeling was treated with DMA (RSA-II manufactured by Rheometrics,
5 ° C / 0 ° C to 350 ° C with a viscoelastic analyzer)
The dynamic viscoelasticity when the temperature was raised in minutes was measured, and the glass transition temperature (maximum tan δ) and the Young's modulus at 250 ° C. (storage modulus E ′) were determined.
At 13 ° C, the Young's modulus at 250 ° C was 2.9 MPa.

[Peel Strength] The above-mentioned resin film A with a PET base material was coated on a 35 μm thick electrolytic copper foil (3EC manufactured by Mitsui Kinzoku Mining Co., Ltd.)
-III foil, Rz = 7.0 μm) at 160 ° C., 0.5 ° C. so that the roughened surface is in contact with the roughened surface of the copper foil and the polyimide film layer.
The lamination was performed under a lamination condition of 1 min. Thereafter, the PET base material is peeled off, and the temperature is 180 ° C. for 5 minutes and 270 ° C.
A curing treatment by heating was performed in the order of -5 minutes to form a polyimide film with a copper foil. Using a tensile tester, determine the bond strength between the copper foil and the polyimide film in the 90-degree direction.
When measured at room temperature under the condition of mm / min, 1.0 kN
/ M.

Example 1 A polyimide precursor resin solution obtained in Synthesis Example 1 was coated on a 100 μm-thick release-treated PET film with a knife coater so that the thickness after drying was 30 μm.
After drying at 120 ° C. for 6 minutes, a polyimide precursor film with a PET film was obtained. The imidation ratio of the obtained polyimide precursor film was measured using an infrared absorption spectrum analysis method, and was about 60% from an absorption peak due to an imide ring generated by imide ring closure, and was partially imidized. It was confirmed that the polyimide precursor was obtained. A laminating temperature of 160 ° C. was applied to this film using a vacuum pressure laminator (MVLP-500, manufactured by Meiki Seisakusho) so that the bump forming surface side of the semiconductor wafer having a bump of 40 μm in the pad portion and the polyimide precursor film were in contact with each other. The laminate was laminated under a pressure of 0.5 MPa and a pressure time of 90 seconds. Thereafter, the PET film was peeled off, and a curing treatment by heating was performed in the order of 180 ° C for 5 minutes and 270 ° C for 5 minutes. When the imidation ratio at this time was measured, the imidation was confirmed to be 95% or more by analysis of the infrared absorption spectrum. In the obtained wafer with an adhesive layer, the height of the bump was higher than the film thickness, and the tip of the bump was appropriately exposed. A small amount of resin residue to serve as an adhesive layer remained at the tip of the bump. Next, this was plasma-treated from above the adhesive layer using a plasma apparatus (V-1000 manufactured by Yamato Scientific Co., Ltd.) under the conditions of a mixed gas atmosphere of CF ₄ and O ₂ , 800 W of RF power, irradiation time of 1 minute, 2 minutes or 3 minutes. The processing was performed to remove the resin residue attached to the upper portion of the bump. As a result of surface analysis of the upper part of the bump by surface elemental analysis at each treatment time, the peak of the Si component in the resin residue layer was sequentially reduced by the plasma treatment, and the resin was removed in about 3 minutes. Was suggested. The wafer with the polyimide film thus obtained was diced to obtain a unit semiconductor element having an area of 1 cm × 1 cm.

A semiconductor package was prepared by mounting the unit semiconductor element on a mounting board with the surface on which the adhesive layer was formed facing downward at a temperature of 320 ° C., a pressure of 2 MPa, and a thermocompression bonding condition of 10 seconds. When a conduction test was performed on the obtained semiconductor package, it was confirmed that good conduction was exhibited. After absorbing moisture for 168 hours at a temperature of 85 ° C. and a humidity of 85% in a thermo-hygrostat at 230 ° C. for 60 seconds in an infrared reflow furnace, a heat resistance test using an infrared reflow furnace was carried out. When the presence / absence of blistering at the interface between the substrate and the mounting board was determined, no blistering or interface peeling was observed.

Example 2 A polyimide precursor with a PET film was prepared in the same manner as in Example 1 except that the step of applying the polyimide precursor resin solution onto the PET film was adjusted so that the thickness after predrying was 45 μm. A film was obtained. Then, under the same conditions as in Example 1, after laminating and peeling the PET film,
Hardened. As a result, the bump was buried under the polyimide film, that is, under the adhesive layer. Instead of the plasma treatment of Example 1, the sample was immersed for 1 minute in a beaker containing a hydrazine solution at 40 ° C., and the surface of the polyimide adhesive layer was etched by about several microns to expose the tip of the bump. A unit semiconductor element was used in the same manner as in Example 1, and a similar test was performed. Almost the same results were obtained.

[0042]

According to the present invention, since the mounting of the mounting substrate and the semiconductor element can be performed via the film-like adhesive layer, a complicated manufacturing process is not required, and the liquid resin is applied. There are no drawbacks such as the generation of bubbles which may be a problem in such a case. In addition, the polyimide film used for mounting has excellent heat resistance, and is not only excellent as an adhesive layer with a small decrease in adhesiveness even when subjected to relatively high-temperature heat in a manufacturing process and the like, but also when unnecessary portions remain after lamination. In addition, this can be removed by a simple method. Therefore,
The industrial utility value of the present invention is very high.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a semiconductor wafer.

FIG. 2 is a partial cross-sectional view of a semiconductor wafer provided with an adhesive layer.

FIG. 3 is a partial cross-sectional view of a semiconductor wafer provided with another adhesive layer.

FIG. 4 is a partial cross-sectional view of a semiconductor wafer from which an adhesive layer on bumps has been removed;

FIG. 5 is a schematic diagram showing a bonding state between a semiconductor element and a mounting substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor wafer 2 Pad 3 Bump 4 Passivation film 5 Circuit 6 Adhesive layer 7 Mounting substrate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J043 PC015 PC016 PC035 PC065 PC115 PC116 PC135 PC136 QB15 QB26 QB31 RA35 SA06 SA49 SA62 SA71 SB01 SB03 TA22 TB01 UA012 UA032 UA041 UA121 UA122 UA131 UA132 UA141 UA142 UA UA UA UA UA UA UA UA UA UA UA UA582 UB011 UB012 UB021 UB022 UB121 UB122 UB131 UB152 UB281 UB301 UB302 UB401 UB402 VA021 VA041 VA061 VA081 WA09 WA16 XA16 XA17 XA19 YA06 YB02 ZA02 ZB01 ZB11 ZB50

Claims (6)

[Claims] A step of preparing a semiconductor wafer having a plurality of pads and a passivation film and having bumps or posts provided on each of said pads, wherein a polyimide precursor film or Forming an adhesive layer by laminating a polyimide film in the range of 50 to 200 ° C., and forming a semiconductor wafer in which the tip of a bump or post is exposed from the surface of the adhesive layer;
And thereafter dicing the semiconductor wafer to form a semiconductor element. 2. The method according to claim 1, wherein the polyimide precursor film or the adhesive layer formed from the polyimide film has the following characteristics. (1) The glass transition temperature is 40 to 250 ° C. (2) The Young's modulus (storage modulus) at 250 ° C. is 1
0 ⁵ Pa or more (3) Peel strength of 0.7 kN when thermocompression bonded to copper foil
/ M or more 3. The polyimide precursor film or polyimide film has a height of 50 to 1 with respect to the height of the bump or post.
3. The method according to claim 1, wherein the thickness of the semiconductor element is 50%. 4. The method according to claim 1, further comprising, after laminating the polyimide precursor film or the polyimide film, exposing at least the tip of the bump or the post by plasma treatment, laser treatment or alkali solution treatment on the adhesive layer on the bump or the post. 4. The method of manufacturing a semiconductor device according to any one of 1 to 3. 5. The polyimide precursor film or the polyimide film is an aromatic tetracarboxylic dianhydride (A)
The method for producing a semiconductor device according to any one of claims 1 to 4, comprising a polyimide precursor resin obtained from diamine (B) containing diamine having a crosslinkable reactive group. 6. A diamine having a crosslinkable reactive group (B1)
Is at least one kind of crosslinkable reactive group selected from phenolic hydroxyl group, carboxyl group and vinyl group, and contains diamine (B1) having a crosslinkable reactive group among all diamines (B). 6. The method according to claim 5, wherein the proportion is 5 to 100 mol%.