JP2013214619A - Semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which can achieve high reliability by inhibiting voids and which has excellent manufacturing efficiency.SOLUTION: A manufacturing method of a semiconductor device in which a plurality of semiconductor chips are mounted on a mother wafer, comprises: an arrangement process of arranging the semiconductor chips on each of which bump electrodes having tips composed of solder on the mother wafer via a joining material; an electrode joining process of heating the semiconductor chips at a temperature to not lower than a solder melting point to fusion join the bump electrodes of the semiconductor chips with electrode parts of the mother wafer and temporarily curing the joining material to a gel percentage of 40% or less; and a bubble removing process of heating the mother wafer in a pressurized atmosphere to remove bubbles included in the joining material after performing the arrangement process and the electrode joining process on all of the semiconductor chips.

Description

The present invention relates to a method for manufacturing a semiconductor device excellent in production efficiency capable of realizing high reliability by suppressing voids.

In recent years, flip-chip mounting using a semiconductor chip having protruding electrodes (bumps) made of solder or the like is frequently used in order to cope with miniaturization and high integration of a semiconductor device that is increasingly developed.
In flip chip mounting, a method is generally used in which a protruding electrode of a semiconductor chip and an electrode portion of a substrate, a mother wafer, another semiconductor chip or the like are melt-bonded and then sealed by injecting an underfill. ing. However, in recent years, semiconductor chips have been miniaturized, and the pitch between the protruding electrodes has become narrower. Along with these, the gap between the semiconductor chip and the substrate, mother wafer, other semiconductor chip, etc. Because of the narrowing, bubbles are easily mixed in when the underfill is injected and remain as voids.

In order to suppress voids, for example, a method of drying an adherend, a method of suppressing gas generated from the underfill resin itself, a method of removing bubbles by evacuating in a sealing process, and the like have been studied. Also, rather than injecting underfill after electrode bonding, a method of applying, printing, or bonding a resin to a semiconductor chip or wafer in advance, and further to a semiconductor chip or wafer that has been applied, printed, or bonded to a resin A method for removing bubbles by applying pressure and heating has been studied.

For example, Patent Document 1 discloses (1) a step of bonding a sheet-like thermosetting resin composition to a pattern surface of a wafer having bumps, and (2) a softening point of the thermosetting resin composition in a pressure resistant container. The step of applying pressure to the wafer by gas compression at a temperature not higher than the curing reaction start temperature, (3) cutting the wafer into chips, and (4) mounting the chip on a printed circuit board. In addition, a method for manufacturing a semiconductor device is described.

However, the conventional method cannot sufficiently eliminate the possibility that voids remain while the process becomes complicated. Also, in the method of applying, printing, or bonding a resin to a semiconductor chip or wafer in advance, since electrode bonding and resin curing are simultaneously performed by heating, it is possible to achieve both high precision electrode bonding and void suppression. It was not easy.

Japanese Patent No. 4397837

It is an object of the present invention to provide a method for manufacturing a semiconductor device excellent in production efficiency that can suppress voids and realize high reliability.

The present invention is a method of manufacturing a semiconductor device in which a plurality of semiconductor chips are mounted on a mother wafer, and a semiconductor chip on which a protruding electrode having a tip portion made of solder is formed is formed on a mother wafer via a bonding material. An arrangement step of arranging and heating the semiconductor chip to a temperature equal to or higher than a solder melting point to melt-bond the protruding electrode of the semiconductor chip and the electrode portion of the mother wafer, and the gelling rate of the bonding material is 40% or less After performing the electrode bonding step of pre-curing, and the placement step and the electrode bonding step for all the semiconductor chips, the mother wafer is heated in a pressurized atmosphere to remove bubbles contained in the bonding material A method for manufacturing a semiconductor device including a removing step.
The present invention is described in detail below.

According to the method of temporarily curing the bonding material to a predetermined gelation rate or less during electrode bonding and then heating the bonding material in a pressurized atmosphere to remove bubbles contained in the bonding material, It has been found that even when air bubbles are mixed into the bonding material, the air bubbles can be removed to suppress voids, and electrode bonding can be performed well to achieve high reliability. By heating the bonding material in a pressurized atmosphere, it is considered that bubbles contained in the bonding material are not simply grown but can be actively removed. In addition, the present inventors have found that production efficiency can be improved by heating a mother wafer having a plurality of semiconductor chips arranged and electrode-bonded in a pressurized atmosphere, thereby completing the present invention. It came.

The semiconductor device manufacturing method of the present invention is a method of manufacturing a semiconductor device in which a plurality of semiconductor chips are mounted on a mother wafer. Note that the plural number is not particularly limited as long as it is two or more.
In the method for manufacturing a semiconductor device according to the present invention, first, an arrangement step is performed in which a semiconductor chip on which a protruding electrode having a tip portion made of solder is formed is arranged on a mother wafer via a bonding material. In this step, the semiconductor chip is placed on the mother wafer so that the protruding electrode of the semiconductor chip and the electrode portion of the mother wafer face each other. The arrangement step can be performed using, for example, a conventionally known bonding apparatus such as a flip chip bonder.

Examples of the semiconductor chip include a semiconductor chip made of a semiconductor such as silicon or gallium arsenide and having a protruding electrode having a tip portion made of solder formed on the surface. Note that the protruding electrode having the tip made of solder may have the entire protruding electrode made of solder as long as it has the tip made of solder.

In the arrangement step, the bonding material may be applied, printed, or bonded to the semiconductor chip side, or the bonding material may be applied, printed, or bonded to the mother wafer.
As a method of applying, printing, or bonding a bonding material to the semiconductor chip side, for example, a method of applying or printing a paste-like bonding material on a surface having a protruding electrode of a semiconductor chip, a film-shaped bonding material using a protruding electrode of a semiconductor chip For example, a method of pasting on the surface to have. In addition, the paste-like bonding material is applied or printed on the surface of the semiconductor wafer having the protruding electrodes to form a coating film, or the film-shaped bonding material is bonded to the surface of the semiconductor wafer having the protruding electrodes, and then the semiconductor wafer. There is also a method of obtaining a semiconductor chip to which a bonding material is adhered.

The method for applying or printing the paste-like bonding material is not particularly limited, and examples thereof include a method using a dispenser device.
The method for laminating the film-like bonding material is not particularly limited, and examples thereof include normal pressure lamination and vacuum lamination. Of these, the vacuum lamination requires a large and expensive apparatus, and therefore the normal pressure lamination is preferable.

In particular, the semiconductor device manufacturing method of the present invention includes a bonding step of bonding a film-like bonding material to the surface of the semiconductor wafer having the protruding electrodes, and heating the semiconductor wafer in a pressurized atmosphere before the placement step. It is preferable to include a lami-void removing step for removing bubbles contained in the film-like bonding material and a dicing step for dicing the semiconductor wafer to obtain a semiconductor chip to which the bonding material is adhered.
By heating the semiconductor wafer in a pressurized atmosphere after laminating the film-like bonding material, even if bubbles are mixed into the bonding material, the bubbles can be removed to suppress voids (lami voids). it can. In addition, a lami void means the bubble produced when bonding a film-like joining material.

Examples of the method for dicing the semiconductor wafer include a method of cutting and separating using a conventionally known grindstone, a laser, or the like.

The bonding material may be in the form of a paste or a film, and is designed to be temporarily cured to a gelation rate of 40% or less during electrode bonding. For this purpose, the bonding material preferably has a relatively long gel time, and more preferably has a gel time at 240 ° C. of 5 seconds or more.
When the gel time is less than 5 seconds, curing proceeds too much during electrode bonding, and as a result, the bubbles may not be sufficiently removed even if the bubble removal step is performed. The gel time is more preferably 10 seconds or longer. In addition, the gel time of a joining material can be calculated | required by measuring the time when a joining material hardens | cures and hardens on a hotplate by contact, such as a spatula.

The upper limit of the gel time at 240 ° C. of the bonding material is not particularly limited, but is preferably 30 seconds or less. When the gel time exceeds 30 seconds, it takes a very long time to completely cure the bonding material, which may affect productivity.

The bonding material preferably contains a curable compound and a curing agent. The combination of the curable compound and the curing agent can control the curability of the bonding material.
The said curable compound is not specifically limited, For example, the compound hardened | cured by reaction, such as addition polymerization, polycondensation, polyaddition, addition condensation, ring-opening polymerization, is mentioned. Specific examples of the curable compound include urea resin, melamine resin, phenol resin, resorcinol resin, epoxy resin, acrylic resin, polyester resin, polyamide resin, polybenzimidazole resin, diallyl phthalate resin, xylene resin, alkyl- Examples thereof include thermosetting compounds such as benzene resin, epoxy acrylate resin, silicon resin, and urethane resin. Especially, since it is excellent in the reliability and joining strength of a semiconductor device, an epoxy resin and an acrylic resin are preferable and the epoxy resin which has an imide skeleton is more preferable.

The epoxy resin is not particularly limited. For example, bisphenol type epoxy resins such as bisphenol A type, bisphenol F type, bisphenol AD type and bisphenol S type, novolac type epoxy resins such as phenol novolak type and cresol novolak type, resorcinol type epoxy Resin, aromatic epoxy resin such as trisphenolmethane triglycidyl ether, naphthalene type epoxy resin, fluorene type epoxy resin, dicyclopentadiene type epoxy resin, polyether modified epoxy resin, NBR modified epoxy resin, CTBN modified epoxy resin, and These hydrogenated products can be mentioned. Among them, bisphenol F type epoxy resin, resorcinol type epoxy resin, and polyether-modified epoxy resin are preferable because a bonding material having a low viscosity can be obtained.

Among the bisphenol F-type epoxy resins, as commercial products, for example, EXA-830-LVP, EXA-830-CRP (manufactured by DIC) and the like can be mentioned. Moreover, EX-201 (made by Nagase ChemteX Corporation) etc. are mentioned as a commercial item among the said resorcinol type epoxy resins. Moreover, as a commercial item among the said polyether modified epoxy resins, EX-931 (made by Nagase ChemteX), EXA-4850-150 (made by DIC), EP-4005 (made by ADEKA) etc. are mentioned, for example. It is done.

The above-mentioned curable compound has a preferable upper limit of moisture absorption of 1.5% and a more preferable upper limit of 1.1%. Examples of the curable compound having such a moisture absorption rate include naphthalene type epoxy resins, fluorene type epoxy resins, dicyclopentadiene type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins and the like.

The curable compound preferably further contains a polymer compound having a functional group capable of reacting with an epoxy resin or the like (also simply referred to as a polymer compound having a reactive functional group). By including such a polymer compound, the bonding reliability when heat distortion occurs is improved.

When an epoxy resin is used as the curable compound as the polymer compound having a reactive functional group, for example, a polymer compound having an amino group, a urethane group, an imide group, a hydroxyl group, a carboxyl group, an epoxy group, or the like. Etc. Among these, a polymer compound having an epoxy group is preferable. By adding the polymer compound having an epoxy group, the cured product of the bonding material exhibits excellent flexibility. That is, the cured product of the bonding material has excellent mechanical strength, heat resistance and moisture resistance derived from the epoxy resin as the curable compound, and excellent flexibility derived from the polymer compound having the epoxy group. Therefore, the heat cycle resistance, solder reflow resistance, dimensional stability and the like are excellent, and high bonding reliability or high conduction reliability is exhibited.

The polymer compound having an epoxy group is not particularly limited as long as it is a polymer compound having an epoxy group at the terminal and / or side chain (pendant position). For example, an epoxy group-containing acrylic rubber, an epoxy group-containing butadiene rubber, Examples thereof include bisphenol type high molecular weight epoxy resin, epoxy group-containing phenoxy resin, epoxy group-containing acrylic resin, epoxy group-containing urethane resin, and epoxy group-containing polyester resin. Among these, an epoxy group-containing acrylic resin is preferable because a polymer compound containing a large amount of epoxy groups can be obtained, and the cured product has better mechanical strength or heat resistance. These polymer compounds having an epoxy group may be used alone or in combination of two or more.

As the polymer compound having a functional group capable of reacting, a polymer compound having the epoxy group, particularly when an epoxy group-containing acrylic resin is used, the preferred lower limit of the weight average molecular weight of the polymer compound having the epoxy group is 1. Ten thousand. When the weight average molecular weight is less than 10,000, the film forming property of the bonding material becomes insufficient, and the flexibility of the cured product of the bonding material may not be sufficiently improved.

When the polymer compound having an epoxy group is used as the polymer compound having a functional group capable of reacting, particularly when an epoxy group-containing acrylic resin is used, the preferred lower limit of the epoxy equivalent of the polymer compound having the epoxy group is 200, A preferred upper limit is 1000. When the epoxy equivalent is less than 200, the flexibility of the cured product of the bonding material may not be sufficiently improved. When the epoxy equivalent exceeds 1000, the mechanical strength or heat resistance of the cured product of the bonding material may be insufficient.

Although the compounding quantity of the high molecular compound which has the said functional group which can react is not specifically limited, The preferable minimum in 100 weight part of the said sclerosing | hardenable compound is 1 weight part, and a preferable upper limit is 40 weight part. If the amount of the polymer compound having a functional group capable of reacting is less than 1 part by weight, sufficient reliability against thermal strain may not be obtained. When the compounding amount of the polymer compound having a functional group capable of reacting exceeds 40 parts by weight, the heat resistance of the bonding material may be lowered.

The said hardening | curing agent is not specifically limited, A conventionally well-known hardening | curing agent can be suitably selected according to the said sclerosing | hardenable compound. When using an epoxy resin as the curable compound, examples of the curing agent include latent heat-curing acid anhydride-based curing agents such as trialkyltetrahydrophthalic anhydride, phenol-based curing agents, amine-based curing agents, and dicyandiamide. For example, a cationic curing agent and a cationic catalyst-type curing agent. These curing agents may be used alone or in combination of two or more.

Although the compounding quantity of the said hardening | curing agent is not specifically limited, When using the hardening | curing agent which reacts equally with the functional group of the said sclerosing | hardenable compound, it is 60-100 equivalent with respect to the functional group amount of the said sclerosing | hardenable compound. preferable. Moreover, when using the hardening | curing agent which functions as a catalyst, as for the compounding quantity of the said hardening | curing agent, a preferable minimum is 1 weight part with respect to 100 weight part of said curable compounds, and a preferable upper limit is 40 weight part.

The bonding material may contain a curing accelerator in addition to the curing agent in order to adjust the curing speed, physical properties of the cured product, and the like.
The said hardening accelerator is not specifically limited, For example, an imidazole series hardening accelerator, a tertiary amine type hardening accelerator, etc. are mentioned. Of these, an imidazole curing accelerator is preferred because it is easy to control the reaction system for adjusting the curing speed and the physical properties of the cured product. These hardening accelerators may be used independently and may use 2 or more types together.

The imidazole-based curing accelerator is not particularly limited. For example, 1-cyanoethyl-2-phenylimidazole in which the 1-position of imidazole is protected with a cyanoethyl group, and an imidazole-based curing accelerator whose basicity is protected with isocyanuric acid (trade name “ 2MA-OK ", manufactured by Shikoku Kasei Kogyo Co., Ltd.), 2MZ, 2MZ-P, 2PZ, 2PZ-PW, 2P4MZ, C11Z-CNS, 2PZ-CNS, 2PZCNS-PW, 2MZ-A, 2MZA-PW, C11Z-A, 2E4MZ-A, 2MAOK-PW, 2PZ-OK, 2MZ-OK, 2PHZ, 2PHZ-PW, 2P4MHZ, 2P4MHZ-PW, 2E4MZ · BIS, VT, VT-OK, MAVT, MAVT-OK (above, Shikoku Chemical Industries, Ltd.) Manufactured) and the like. These imidazole type hardening accelerators may be used independently and may use 2 or more types together.

The compounding quantity of the said hardening accelerator is not specifically limited, A preferable minimum is 1 weight part with respect to 100 weight part of said curable compounds, and a preferable upper limit is 10 weight part.

When an epoxy resin is used as the curable compound and the curing agent and the curing accelerator are used in combination, the blending amount of the curing agent used is equivalent to the theoretically required equivalent to the epoxy group in the epoxy resin to be used. The following is preferable. If the blending amount of the curing agent exceeds the theoretically required equivalent, chlorine ions may be easily eluted by moisture from a cured product obtained by curing the bonding material. That is, if the curing agent is excessive, for example, when the elution component is extracted from the cured material of the bonding material with hot water, the pH of the extracted water becomes about 4 to 5, so that a large amount of chloride ions are eluted from the epoxy resin. There are things to do. Accordingly, it is preferable that the pH of the pure water after 1 g of the cured product of the bonding material is immersed in 10 g of pure water at 100 ° C. for 2 hours is 6 to 8, and the pH is 6.5 to 7.5. More preferred.

The bonding material may contain a diluent in order to reduce the viscosity.
The diluent preferably has an epoxy group, and the preferable lower limit of the number of epoxy groups in one molecule is 2, and the preferable upper limit is 4. If the number of epoxy groups in one molecule is less than 2, sufficient heat resistance may not be exhibited after the bonding material is cured. If the number of epoxy groups in one molecule exceeds 4, distortion due to curing may occur, or uncured epoxy groups may remain, which may result in poor bonding strength or poor bonding due to repeated thermal stress. May occur. A more preferable upper limit of the number of epoxy groups in one molecule of the diluent is 3.
The diluent preferably has an aromatic ring and / or a dicyclopentadiene structure.

The preferable upper limit of the weight loss at 120 ° C. and the weight loss at 150 ° C. is 1%. If the weight loss at 120 ° C. and the weight loss at 150 ° C. exceed 1%, the unreacted material volatilizes during or after the bonding material is cured, which adversely affects productivity or performance of the semiconductor device. Sometimes.
The diluent preferably has a lower curing start temperature and a higher curing rate than other curable compounds.

The preferable lower limit of the blending amount of the diluent in the bonding material is 1% by weight, and the preferable upper limit is 20% by weight. If the blending amount of the diluent is out of the above range, the viscosity of the bonding material may not be sufficiently reduced.

It is preferable that the bonding material further contains a thixotropic agent. By containing the thixotropic agent, the bonding material can achieve a desired viscosity behavior.
The thixotropy imparting agent is not particularly limited, and examples thereof include fine metal particles, calcium carbonate, fumed silica, inorganic fine particles such as aluminum oxide, boron nitride, aluminum nitride, and aluminum borate. Of these, fumed silica is preferable. Moreover, as the thixotropy-imparting agent, a thixotropy-imparting agent subjected to surface treatment can be used as necessary. In particular, it is preferable to use particles having a hydrophilic group on the surface as the thixotropic agent. Specific examples of the particles having a hydrophilic group on the surface include fumed silica having a hydrophilic group on the surface.

When a particulate thixotropy imparting agent is used as the thixotropy imparting agent, the preferable upper limit of the average particle diameter is 1 μm. When the average particle diameter of the thixotropy-imparting agent exceeds 1 μm, the bonding material may not exhibit the desired thixotropy.

The blending amount of the thixotropy imparting agent in the bonding material is not particularly limited, but a preferred lower limit is 0.5% by weight and a preferred upper limit is 20% by weight. If the blending amount of the thixotropy-imparting agent is less than 0.5% by weight, sufficient thixotropy may not be imparted to the bonding material. If the amount of the thixotropy-imparting agent exceeds 20% by weight, the exclusion property of the bonding material may be lowered. A more preferable lower limit of the amount of the thixotropy-imparting agent is 3% by weight, and a more preferable upper limit is 10% by weight.

It is preferable that the bonding material further contains a surface-treated silica filler. Although the said surface-treated silica filler is not specifically limited, The silica filler surface-treated with the phenylsilane coupling agent is preferable.

The amount of the surface-treated silica filler is not particularly limited, but a preferable lower limit is 30 parts by weight and a preferable upper limit is 400 parts by weight with respect to 100 parts by weight of the curable compound. When the blending amount of the surface-treated silica filler is less than 30 parts by weight, the bonding material may not be able to maintain sufficient reliability. When the compounding amount of the surface-treated silica filler exceeds 400 parts by weight, the viscosity of the bonding material becomes too high, and the coating stability may be lowered.

The bonding material may contain a solvent as necessary.
The solvent is not particularly limited, and examples thereof include aromatic hydrocarbons, chlorinated aromatic hydrocarbons, chlorinated aliphatic hydrocarbons, alcohols, esters, ethers, ketones, glycol ethers (cellosolves), and fats. Examples thereof include cyclic hydrocarbons and aliphatic hydrocarbons.

The said joining material may contain an inorganic ion exchanger as needed.
Among the inorganic ion exchangers, examples of commercially available products include IXE series (manufactured by Toagosei Co., Ltd.). A preferable upper limit of the amount of the inorganic ion exchanger in the bonding material is 10% by weight, and a preferable lower limit is 1% by weight.

The said bonding | jointing material may contain other additives, such as adhesive imparting agents, such as a bleed inhibitor and an imidazole silane coupling agent, and an adhesive imparting agent as needed.

In the bonding material, the preferable lower limit of the minimum melt viscosity in the temperature range from room temperature to the solder melting point is 0.1 Pa · s, and the preferable upper limit is 10 ⁴ Pa · s. If the minimum melt viscosity is less than 0.1 Pa · s, the fillet may protrude too much and contaminate other devices. If the minimum melt viscosity exceeds 10 ⁴ Pa · s, voids may not be sufficiently suppressed.
The minimum melt viscosity in the temperature range from room temperature to the solder melting point can be measured using a rheometer.

The method for producing the bonding material is not particularly limited. For example, a curing accelerator, a polymer compound having a functional group capable of reacting, a thixotropy imparting agent, and other additives as necessary to the curable compound and the curing agent. A method of mixing a predetermined amount of the above and the like. The mixing method is not particularly limited, and examples thereof include a method using a homodisper, a universal mixer, a Banbury mixer, a kneader and the like.

In the method for manufacturing a semiconductor device of the present invention, the semiconductor chip is then heated to a temperature equal to or higher than the solder melting point to melt-bond the protruding electrode of the semiconductor chip and the electrode portion of the mother wafer, and An electrode joining step is performed in which the gelation rate is temporarily cured to 40% or less.
By performing such a process and then performing a bubble removal process, even if bubbles are mixed into the bonding material, the bubbles can be removed and voids can be suppressed, and electrode bonding can be improved. It can be carried out. The electrode bonding step can be performed using, for example, a conventionally known bonding apparatus such as a flip chip bonder.

Examples of the mother wafer include a wafer made of a semiconductor such as silicon or gallium arsenide, and an electrode portion made of solder or a surface treated (OSP, Au / Ni, Sn plating, etc.) Cu electrode formed on the surface.

As a method of heating the semiconductor chip to a temperature equal to or higher than the solder melting point to melt-bond the protruding electrode of the semiconductor chip and the electrode portion of the mother wafer, for example, while heating the semiconductor chip to a temperature equal to or higher than the solder melting point For example, a method of applying a load to the semiconductor chip may be used. The solder melting point is usually about 225 to 235 ° C.
Although the temperature which heats the said semiconductor chip is not specifically limited, A preferable minimum is 240 degreeC and a preferable upper limit is 400 degreeC. The load applied to the semiconductor chip is not particularly limited, but a preferred lower limit is 10N and a preferred upper limit is 200N.

If the gelation rate of the bonding material exceeds 40%, voids cannot be sufficiently suppressed. The gelling rate of the bonding material is preferably 30% or less.
The lower limit of the gelation rate of the bonding material is not particularly limited, but is preferably 3% or more. When the gelation rate of the bonding material is less than 3%, the retention of the protruding electrode is lowered. Therefore, when a brittle material such as a low-k material is used as the insulating interlayer film, the insulating interlayer film is heated. Insufficient stress relaxation may cause the insulating interlayer film immediately below the bump electrode to break down or peel off.
The gelation rate (%) of the bonding material means a value obtained by the following formula (1).
Gelling rate of bonding material (%) = (1−Dh / Di) × 100 (1)
In formula (1), Di represents the heating value in the initial state of the bonding material calculated by the differential scanning calorimeter, and Dh represents the heating value after the heat treatment of the bonding material calculated by the differential scanning calorimeter. .

In the method for manufacturing a semiconductor device according to the present invention, after the placement step and the electrode bonding step are performed on all semiconductor chips, the mother wafer is heated in a pressurized atmosphere, and bubbles contained in the bonding material are removed. The bubble removal process to remove is performed.
Under a pressurized atmosphere means a pressure atmosphere higher than normal pressure (atmospheric pressure). By performing such a process, even if bubbles are mixed into the bonding material, the bubbles can be removed and the voids can be suppressed. Here, it is considered that the bubbles contained in the bonding material are not simply grown but can be positively removed.

Examples of a method for heating the mother wafer under a pressurized atmosphere include a method using a pressure curing oven (for example, PCO-083TA manufactured by NTT Atvans Technology). The pressure curing oven may be an air atmosphere, but is preferably an inert gas atmosphere such as nitrogen.

The preferable lower limit of the pressure of the pressure curing oven is 0.1 MPa, and the preferable upper limit is 10 MPa. If the pressure is less than 0.1 MPa, bubbles may not be sufficiently removed. When the pressure exceeds 10 MPa, the bonding material itself is deformed, which may adversely affect the reliability of the semiconductor device. The more preferable lower limit of the pressure is 0.3 MPa, and the more preferable upper limit is 1 MPa.
The temperature of the pressure curing oven is preferably set with reference to the minimum melt viscosity of the bonding material, and specifically, preferably within a range of ± 20 ° C. of the temperature at which the bonding material exhibits the minimum melt viscosity. .

In the method for manufacturing a semiconductor device of the present invention, after performing the placement step and the electrode bonding step for all the semiconductor chips, a mother wafer in which a plurality of semiconductor chips are placed and electrode-bonded is applied in a pressurized atmosphere. Since the heating is performed, the semiconductor device manufacturing method of the present invention is a method with excellent production efficiency.

In the bubble removal step, the bonding material is also cured. However, the bonding material may be completely cured, or it is cured to an intermediate stage, and then the curing step is performed to completely cure the bonding material. It's okay.
As a method of completely curing the bonding material, for example, a method of heating the bonding material by raising the temperature of the pressure curing oven to completely cure, the heating of the bonding material under normal pressure, and complete curing And the like. Among these, from the viewpoint of the number of steps, a method in which the temperature of the pressure curing oven is raised to heat the bonding material and completely cure is preferable.

According to the method for manufacturing a semiconductor device of the present invention, even if air bubbles are mixed in the bonding material, the air bubbles can be removed and voids can be suppressed, and electrode bonding can be performed well and high reliability can be achieved. Can be realized. In addition, according to the method for manufacturing a semiconductor device of the present invention, since the mother wafer in which a plurality of semiconductor chips are arranged and electrode-bonded is heated in a pressurized atmosphere, production efficiency can be improved.
A semiconductor device in which a plurality of semiconductor chips are mounted on a mother wafer manufactured by the method for manufacturing a semiconductor device of the present invention, for example, is re-wired from an electrode, or is sealed for each semiconductor chip or in a lump. After the back grinding process of the mother wafer, each semiconductor chip is separated into pieces by dicing and used for manufacturing further electronic components.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the semiconductor device excellent in the production efficiency which can suppress a void and can implement | achieve high reliability can be provided.

Examples of the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1
(1) Manufacture of film-like bonding material According to the composition described in Table 1, each material was added to MEK as a solvent, and a bonding material composition was manufactured by stirring and mixing using a homodisper. The obtained bonding material composition was coated on a release PET using an applicator so that the thickness after drying was 20 μm, and dried to produce a film-shaped bonding material. With respect to the obtained bonding material, the gel time at 240 ° C. was measured and found to be 10 seconds. The gel time of the bonding material was determined by measuring the time during which the bonding material hardens and hardens on a hot plate by contact with a spatula or the like.

(2) Manufacture of semiconductor device (2-1) Adhesion process, dicing process Semiconductor wafer (200 mmφ size, 725 μm) with protruding electrodes (30 μm □, height 15 μm (Cu 10 μm, solder 5 μm)) formed in a peripheral shape at a pitch of 50 μm Thickness) was prepared.
The obtained film-like bonding material was bonded to a surface having a protruding electrode of a semiconductor wafer at 80 ° C. under normal pressure using a normal pressure heating laminator (sticking step). Subsequently, the back surface of the semiconductor wafer was ground using a grinding apparatus (DFG8560, manufactured by Disco Corporation) until the thickness became 50 μm. A dicing tape is affixed to the ground surface of the semiconductor wafer, and the dicing apparatus (DFD651, manufactured by Disco Corporation) is used to dice the semiconductor wafer at a feed rate of 20 mm / second, and the obtained semiconductor chips are picked up and packed in a tray. Thus, a semiconductor chip (7.6 mm □) to which a bonding material having a thickness of 20 μm was attached was obtained (dicing step).

(2-2) Arrangement Step, Electrode Bonding Step A mother wafer (200 mmφ size, 725 μm thickness) on which an electrode portion (25 μm □, surface Au / Ni treatment, height 5 μm) was formed was prepared.
Using a flip chip bonder (FC-3000, manufactured by Toray Engineering Co., Ltd.), the obtained semiconductor chip to which the bonding material is attached is placed on the mother wafer via the bonding material (placement step), and 280 ° C. at 160 ° C. contact. The bump electrode of the semiconductor chip and the electrode portion of the mother wafer were melt bonded at a temperature increase of 20 N for 2 seconds at a stage temperature of 120 ° C. (electrode bonding process). This operation was repeated for 16 semiconductor chips, and the 16 semiconductor chips were sequentially arranged on the mother wafer and electrode-bonded.
At this time, the gelation rate of the bonding material was 5%. Note that the gelation rate (%) of the bonding material is obtained by separately preparing a sample for measuring the gelation rate under the same conditions, peeling off the semiconductor chip from the obtained sample, scraping part of the bonding material, and DSC 6220 It calculated | required by Formula (1) from the emitted-heat amount measured by (Seiko Instruments company make).

(2-3) Bubble removal step The mother wafer on which the 16 semiconductor chips obtained were placed and electrode-bonded was put into a pressure cure oven (PCO-083TA, manufactured by NTT Advanced Technology) and subjected to the following pressure and heating. Bubbles were removed under certain conditions and the bonding material was cured (bubble removal step) to obtain a semiconductor device on which 16 semiconductor chips were mounted.
<Pressurization and heating conditions>
STEP1: Constant temperature increase from 25 ° C to 80 ° C in 10 minutes, 0.5 MPa
STEP2: Hold at 80 ° C. for 60 minutes, 0.5 MPa
STEP3: Constant temperature increase from 80 ° C to 170 ° C, 0.5 MPa
STEP 4: Hold at 170 ° C. for 10 minutes, 0.5 MPa
STEP5: Temperature drop from 170 ° C to 25 ° C in 30 minutes, 0.5 MPa
STEP6: Constant temperature drop to room temperature in 60 minutes, 0.5 MPa

(2-4) Package singulation process For the semiconductor device mounted with 16 semiconductor chips obtained, after sealing the semiconductor chip portion with mold resin, dicing into one substrate size (15 mm □), 16 packages were obtained.

(Example 2)
Example 1 except that the conditions in the electrode joining step were changed to 280 ° C. heating at 160 ° C., a load of 20 N for 5 seconds and a stage temperature of 120 ° C., and the gelation rate of the joining material at this time was 35%. In the same manner, 16 packages were obtained.

(Example 3)
Sixteen packages were obtained in the same manner as in Example 1 except that the conditions in the attaching step were changed to vacuum lamination at 80 Pa and 80 ° C. (manufactured by ATM-812M Takatori).

Example 4
Sixteen packages were obtained in the same manner as in Example 1 except that the conditions in the bubble removal step were changed to the following pressure and heating conditions.
<Pressurization and heating conditions>
STEP1: Constant temperature increase from 25 ° C to 100 ° C in 10 minutes, 0.5 MPa
STEP 2: Hold at 100 ° C. for 60 minutes, 0.5 MPa
STEP 3: Constant temperature increase from 100 ° C to 170 ° C, 0.5 MPa
STEP 4: Hold at 170 ° C. for 10 minutes, 0.5 MPa
STEP5: Temperature drop from 170 ° C to 25 ° C in 30 minutes, 0.5 MPa
STEP6: Constant temperature drop to room temperature in 60 minutes, 0.5 MPa

(Comparative Example 1)
Sixteen packages were obtained in the same manner as in Example 1 except that the conditions in the bubble removal step were changed to the following pressurization and heating conditions (no pressurization was performed).
<Pressurization and heating conditions>
STEP1: Constant temperature increase in 10 minutes from 25 ° C to 80 ° C, 0.1 MPa (1 atm)
STEP 2: Hold at 80 ° C. for 60 minutes, 0.1 MPa (1 atm)
STEP3: Constant temperature increase from 80 ° C to 170 ° C, 0.1 MPa (1 atm)
STEP 4: Hold at 170 ° C. for 10 minutes, 0.1 MPa (1 atm)
STEP5: Temperature drop from 170 ° C to 25 ° C in 30 minutes, 0.1 MPa (1 atm)
STEP 6: Constant temperature drop in 60 minutes to room temperature, 0.1 MPa (1 atm)

(Comparative Example 2)
Example 1 except that the conditions in the electrode joining step were changed to 280 ° C. heating at 160 ° C., 10 N load at 20 N, and stage temperature 120 ° C., and the gelation rate of the joining material at this time was 50%. In the same manner, 16 packages were obtained.

(Evaluation)
The following evaluation was performed on the semiconductor devices or packages obtained in the examples and comparative examples. The results are shown in Table 1.

(1) Presence / absence of voids Using an ultrasonic exploration imaging apparatus (C-SAM D9500, manufactured by Nihon Burns Co., Ltd.), the voids of the semiconductor device before and after the bubble removal process were observed, and the presence / absence of voids was evaluated.

(2) Connection reliability The connection reliability was evaluated by performing a temperature cycle test on the 16 packages obtained. In the temperature cycle test, precondition conditions were set to JEDEC LEVEL3 test condition B, and the conditions were −55 ° C. to 125 ° C. and 1000 cycles. Evaluation was made by determining the non-defective product ratio among the 16 packages, with the resistance value after the test being conducted within ± 5% of the initial value as a good product standard.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the semiconductor device excellent in the production efficiency which can suppress a void and can implement | achieve high reliability can be provided.

Claims (3)

A method of manufacturing a semiconductor device in which a plurality of semiconductor chips are mounted on a mother wafer,
An arrangement step of arranging a semiconductor chip on which a protruding electrode made of solder is formed on a mother wafer via a bonding material;
Electrode bonding in which the semiconductor chip is heated to a temperature equal to or higher than the solder melting point to melt-bond the protruding electrode of the semiconductor chip and the electrode portion of the mother wafer, and to temporarily cure the bonding material to a gelation rate of 40% or less. Process,
A bubble removing step of removing the bubbles contained in the bonding material by heating the mother wafer in a pressurized atmosphere after performing the placement step and the electrode bonding step for all semiconductor chips. A method for manufacturing a semiconductor device. The method for manufacturing a semiconductor device according to claim 1, wherein the bonding material has a gel time at 240 ° C. of 5 seconds or more. Prior to the placement step, the film bonding material is bonded to the surface of the semiconductor wafer having the protruding electrodes, and the semiconductor wafer is heated in a pressurized atmosphere to remove bubbles contained in the film bonding material. 3. The method of manufacturing a semiconductor device according to claim 1, further comprising: a lami-void removing step for dicing, and a dicing step for dicing the semiconductor wafer to obtain a semiconductor chip having a bonding material attached thereto.