JP2016039341A - Method of manufacturing electronic component and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic component manufacturing method which can form an electromagnetic shield layer having high adhesion to an electronic component; and sufficiently inhibit deterioration in the electronic component itself; and which requires no complicated process.SOLUTION: A method of manufacturing an electronic component includes the steps of: preparing a semiconductor element mounting substrate including a base material, a semiconductor element placed on one surface of the base material and an encapsulation material for encapsulating the semiconductor element; attaching a protective film to the other surface of the base material; performing a plasma treatment on a surface of the encapsulation material; and forming an electroless plating film on the surface of the encapsulation material subjected to the plasma treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electronic component manufacturing method and an electronic component.

  Electromagnetic waves emitted by electronic devices can sometimes be harmful to the human body. There are a wide variety of methods for shielding such electromagnetic waves (electromagnetic shield), but generally, a metal cap method that covers the inside of an electronic device using a metal cap is the mainstream. However, when this metal cap method is adopted, not only the assembly process of the electronic device becomes very complicated, but also the mounting area of the metal cap has design restrictions, making it difficult to reduce the size and thickness of the electronic device. is there. In addition, it is known that the manufacturing cost of the electronic device itself increases when assembly costs and material costs are included. For this reason, an attempt has been made to obtain an electromagnetic shielding characteristic by forming a plating film directly on the surface of the sealing material of the semiconductor element instead of the metal cap.

  By the way, the method of forming a plating film with high adhesion on the surface of a resin or the like has been performed by various methods for a long time. For example, chromic acid-sulfuric acid is used in the automotive field, and permanganic acid is used in the field of printed circuit boards such as wiring boards to enhance the anchor effect by securing the resin surface and ensuring adhesion between the resin and the plating film. The processing method to do is mainstream. However, there are almost no examples in which such a method is applied to a package substrate including a sealing material mounted with a semiconductor, and it has not yet been put into practical use in mass production. This is because the entire electronic component is treated with these liquids in the process of the above method, and there is a concern about damage to the electronic component itself with the sealing material on the front surface and the package substrate exposed on the back surface or side surface. Because.

  In addition, in order to avoid such damage, the method of protecting an exposed surface suitably using a protective film is also examined. However, when a highly oxidizing liquid such as chromic acid-sulfuric acid or permanganic acid is used, there is a risk that penetration may occur between the substrate and the protective film. Not only that, depending on the type of film, there is a risk of dissolution in these liquids. As described above, the method of treating the target surface with a liquid having high oxidizing power in order to enhance the anchor effect has many risks, making it difficult to put it into practical use in the semiconductor field.

For this reason, in recent examples, an attempt has been made to develop a method for forming an electroless plating film (electromagnetic shielding film) with high adhesion on the surface of the sealing material using high-pressure CO _{2 in a} supercritical state. (Patent Document 1).

JP 2010-114291 A

However, when processing is actually performed using high-pressure CO ₂ in a supercritical state, the electronic component is exposed to a high-pressure environment. At this time, the high-pressure CO _{2 in a} supercritical state may be immersed from the side surface of the package substrate where the glass cloth is exposed, the bonding surface between the sealing material and the substrate, and the resin contained in the package substrate may be dissolved. is there. Therefore, there is a possibility that the component parts themselves are disassembled apart. In the first place, since a process using high-pressure CO ₂ in a supercritical state is introduced during the manufacturing process, there is a limit to simplifying the manufacturing process.

Furthermore, high-pressure CO _{2 in a} supercritical state exhibits a strong solubility even for a protective film provided to protect the back surface (the solder ball mounting surface) of the package substrate. In Patent Document 1, in order to cope with this, the back surfaces of the substrates face each other, the substrate end is sealed with an epoxy adhesive, and finally the cured epoxy resin is removed. The process is performed.

Further, as described in Patent Document 1, when a palladium (Pd) catalyst adhesion treatment using high-pressure CO _{2 in a} supercritical state is performed on the surface on which the sealing material is formed on the package substrate, the immersed metal ions It is conceivable that this migration occurs.

  As described above, it is extremely difficult to put the prior art into practical use and improve the manufacturing process of the electronic component. Even if it can be put into practical use, the degree of freedom in processing the electronic component is low, and the design range is considered to be extremely limited.

  The present invention has been made to solve the above problems, and can form an electromagnetic shield layer having high adhesion to an electronic component and can sufficiently suppress deterioration of the electronic component itself. An object of the present invention is to provide a method of manufacturing an electronic component that does not require complicated steps. Moreover, an object of this invention is to provide the electronic component manufactured by this manufacturing method.

  As a result of intensive studies and examinations, the inventors have found that the above-described problems can be solved by the following production method of the present invention, and have completed the present invention.

  That is, the present invention includes a step of preparing a semiconductor element mounting substrate including a base material, a semiconductor element disposed on one surface of the base material, and a sealing material for sealing the semiconductor element; Provided is a method for manufacturing an electronic component, comprising: a step of attaching a protective film to a surface; a step of plasma treating a surface of a sealing material; and a step of forming an electroless plating film on the surface of the sealing material subjected to plasma treatment To do.

  According to the present invention, for example, an electroless plating film having electromagnetic shielding properties and high adhesion can be formed on the surface of the sealing material of an electronic component and the exposed surface of the package substrate. Provided is a method for manufacturing an electronic component that can be sufficiently suppressed and that does not require complicated steps.

  In the present invention, the plasma treatment is performed using microwave plasma, high frequency plasma, atmospheric pressure plasma, ICP (inductively coupled plasma), HCP (hollow cathode plasma), or special plasma in which ICP and HCP are combined. It is preferable. Regardless of which plasma is used, there is a certain effect, and peeling and swelling of the electroless plating can be effectively suppressed as compared with the case where the plasma treatment is not performed.

  The present invention also provides an electronic component manufactured by the above manufacturing method. The electronic component manufactured in this way is not only provided with an electromagnetic shield with high adhesion, but also deterioration due to the manufacturing environment is sufficiently suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to form an electromagnetic shielding layer with high adhesiveness with respect to an electronic component, deterioration of an electronic component itself can fully be suppressed, and a complicated process is unnecessary. A manufacturing method can be provided.

  Moreover, this invention can provide the electronic component manufactured by this manufacturing method. That is, according to the present invention, plasma processing is performed on the surface of the sealing material and the exposed surface of the package substrate for an electronic component including at least one semiconductor element on the package substrate and a sealing material that covers the entire surface of the semiconductor element. After the electroless plating, an electromagnetic shielding layer having high adhesion was formed without using an oxidizing substance such as a supercritical fluid, chromic acid-sulfuric acid or permanganic acid in the manufacturing process. Electronic parts can be easily manufactured.

It is sectional drawing of the electronic component obtained by the manufacturing method of the electronic component of this embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  The method for manufacturing an electronic component of the present embodiment includes a step of preparing a base material, a semiconductor element disposed on one surface of the base material, and a semiconductor element mounting substrate including a sealing material for sealing the semiconductor element; A step of attaching a protective film to the other surface of the substrate, a step of plasma-treating the surface of the sealing material, and a step of forming an electroless plating film on the surface of the plasma-treated sealing material. More specifically, the electronic component manufacturing method of the present embodiment includes, for example, a step of mounting and arranging a semiconductor element connected to the package substrate on one surface of the package substrate (preparation step), and a semiconductor that is mounted and arranged A step of sealing the element with a sealing material (sealing step), a step of attaching a protective film to the other surface of the package substrate (protective film attaching step), and a package substrate configured through these steps, A process (plasma treatment process) of plasma processing the entire electronic component in which a semiconductor element, a sealing material and a film for protecting the solder ball mounting surface are integrated, and an electroless plating film on the surface of the entire plasma processed electronic component Forming a process (plating process).

  Thereby, the electronic component with a protective film in which the plating film was formed as shown in FIG. 1 can be obtained. FIG. 1 is a cross-sectional view of an electronic component obtained by the electronic component manufacturing method of the present embodiment. FIG. 1A shows a base material 10, a semiconductor element 20 on one surface of the base material, and a part of one surface of the base material 10 (the semiconductor element 20 is placed). The sealing material 30 covering the surface of a part of the portion not formed), the protective film 40 on the other surface (solder ball mounting surface) of the base material 10, and all these surfaces, that is, the sealing material 30. Electroless plating film 50 that covers the surface of the substrate, the surface of the protective film 40, the surface of one surface of the substrate 10 (the portion not covered with the sealing material 30) and the end surface. It is sectional drawing of a subsequent electronic component.

  On the other hand, as shown in FIG. 1B, the sealing material 30 may cover the entire surface of one surface of the substrate 10. That is, FIG. 1B shows the base material 10 and the semiconductor element 20 on one surface of the base material, and the semiconductor element 20 is sealed and the one surface of the base material 10 (the semiconductor element 20 is placed). And the protective film 40 on the other surface (solder ball mounting surface) of the substrate 10, and all these surfaces, that is, the surface of the sealing material 30, the protective film 40. It is sectional drawing of the electronic component after a plating process provided with the electroless plating film | membrane 50 which coat | covers the surface of this, and the end surface of the base material 10. FIG.

  Hereinafter, although each process is explained in full detail, this embodiment is not specifically limited to the content demonstrated here.

[Preparation process]
In this step, a plurality of semiconductor elements are mounted and arranged on one surface of a package substrate (base material) by wire bonding mounting or flip chip mounting to prepare a semiconductor element mounting substrate. As a package substrate, a substrate for semiconductor mounting on which a wiring formed of a glass epoxy substrate, a polyimide substrate, a ceramic substrate, a lead frame or the like is used is used. Examples of semiconductor elements include general-purpose LSIs, flash memories, CPUs, ASICs, system LSIs, DRAMs, SRAMs, and the like.

[Sealing process]
Next, in this step, each semiconductor element is sealed with a sealing material to obtain a sealed semiconductor element mounting substrate. Although the sealing method is not particularly limited, a method of partially sealing the semiconductor element on the package substrate using a sealing material such as a tablet or a liquid can be used. Since an electroless plating film is formed on the surface of the sealing material, the package substrate is designed in advance so that the electroless plating film (copper plating film, nickel plating film, etc.) is connected to the ground pattern. Has been. As will be described later, an electrolytic plating film (a copper plating film, a nickel plating film, etc.) may be further provided on the electroless plating film. Thereby, the electromagnetic shielding effect can be further increased.

  The sealing material is not particularly limited as long as it is usually used as a semiconductor sealing material. For example, an epoxy resin-based sealing material containing a silica filler, a silicone-based sealing material, or the like can be used. In general, an epoxy resin-based sealing material can be suitably used.

  Note that the package substrate including a plurality of semiconductor elements sealed in this way is finally cut and divided into individual chips. For this reason, the package substrate is generally subjected to cutting dicing.

[Protective film pasting process]
In this step, a protective film is attached to the back surface (solder ball mounting surface) which is the other surface of the package substrate. The protective film is used mainly for the purpose of protecting the back surface of the substrate from the plating solution in the subsequent plating step, that is, preventing the back surface of the substrate from being plated.

  As the protective film, a general film for plating protection can be used, and it is not particularly limited as long as it has plating solution resistance, sufficient adhesive strength to the back surface of the substrate, and easy peelability after the plating step. As such a protective film, for example, an acrylic, synthetic rubber, modified rubber or the like is used for the pressure-sensitive adhesive layer, and a protective film using a PET film, PP film, high-strength PE film, or the like is suitably used for the support substrate. Can be used. In addition, it is preferable to perform a protective film sticking process before a plasma treatment process. Although it does not specifically limit as a method of affixing a protective film, The method of affixing by roll lamination at the affixing temperature of 60-80 degreeC is mentioned.

[Plasma treatment process]
Plasma treatment is performed in this step on the sealed semiconductor element mounting substrate obtained in the above step. In this embodiment, it is important to perform this plasma treatment as a pretreatment for improving the electroless plating film adhesion.

  Plasma is a state in which molecules constituting a gas are partially or completely ionized, and are freely moving into cations and electrons. When the electronic component is processed using a gas in a plasma state, a chemical reaction on the surface of the electronic component proceeds to cause oxidation or ashing. By utilizing this reaction, it is possible to form a coating film with good adhesion of the plating film on the entire surface of the electronic component including the surface of the sealing material.

  The plasma used here is not particularly limited, but several examples can be given. Typical examples include microwave plasma, high frequency plasma, atmospheric pressure plasma, ICP (inductively coupled plasma), HCP (hollow cathode plasma), and special plasma in which ICP and HCP are combined. By performing plasma treatment using these plasmas, roughened shapes and active functional groups are added to the surfaces of sealing materials, package substrates, protective films, etc., compared to untreated cases. Thus, the adhesion of these surfaces to the plating film is greatly improved. Among these plasmas, microwave plasma or special plasma combining ICP and HCP is preferable from the viewpoint of etching performance and versatility of the resin material.

  For the plasma treatment, a gas called a carrier gas is used. Examples of the carrier gas used include oxygen, fluorine, hydrogen, argon, and nitrogen. These gases may be mixed and used. Although not particularly limited, a carrier gas in which nitrogen and fluorine are combined mainly with oxygen gas is preferable from the viewpoint of plasma state retention and carrier gas cost.

  The plasma processing is performed in vacuum using a vacuum plasma processing apparatus or the like. Although not particularly limited, the processing pressure is preferably in the range of 200 to 400 mTorr, more preferably in the range of 300 to 400 mTorr, and even more preferably 325 to 375 mTorr. When the processing pressure is 200 mTorr or more, the plasma is easily held, and when it is 400 mTorr or less, the etching tends to be uniformly performed.

  The plasma treatment time is preferably 1 to 60 minutes, more preferably 5 to 40 minutes, and further preferably 10 to 40 minutes. If the treatment time is less than 1 minute, it is difficult to obtain a sufficient effect, and if it exceeds 60 minutes, the substrate tends to be etched too much or the parts are damaged.

[Plating process]
In this step, an electroless plating film is formed on the surface of the sealed semiconductor element mounting substrate that has been subjected to the plasma treatment. As shown in FIGS. 1A and 1B, the electroless plating film is preferably formed on the entire surface of the sealed semiconductor element mounting substrate to which a protective film is attached. In the present embodiment, an electroless plating film having a high adhesion force between the surface subjected to the plasma treatment and the electroless plating film and having a good appearance is formed.

  Although the plating method in this embodiment is not specifically limited, The electroless plating generally used in the manufacturing process of a printed wiring board can be used.

  The electroless plating is not particularly limited, but the following generally performed steps can be used.

  First, as a pretreatment, the surface to be plated is degreased. As the degreasing liquid, an alkaline degreasing liquid or an acidic degreasing liquid can be used. Preferably, an alkaline degreasing solution is effective for removing oil and fat adhering to the target surface. Specifically, the target surface may be treated for about 5 to 10 minutes using an alkaline degreasing solution adjusted to 40 to 60 ° C. In addition, when the alkaline degreasing liquid containing surfactant is used, it is preferable to perform water washing for 2 to 3 minutes after that, and to remove the surfactant adhering to the target surface.

  Next, a pre-dip process is performed to remove moisture on the target surface. For example, the target surface may be treated for 1 to 3 minutes with a pre-dip treatment liquid adjusted to 20 to 30 ° C. Thereafter, the catalyst adhesion treatment is performed without washing with water.

  In the catalyst adhesion treatment, a catalyst that becomes a catalyst nucleus when the electroless plating film is formed is adhered to the target surface. The catalyst is not particularly limited, and examples thereof include noble metals such as copper, copper-nickel alloy, platinum, silver, and palladium, and among these, generally used palladium is preferable. By pre-treating the target surface with a catalyst solution containing a noble metal colloid such as palladium for 5 to 10 minutes, the catalyst can be attached to the target surface. In addition, in order to improve the plating precipitation property by a palladium catalyst, you may perform an adhesion promotion process further. Examples of the adhesion promoting treatment include a treatment for removing tin contained in the catalyst adsorbed on the catalyst surface. Such treatment is mainly performed using an acidic liquid, and the treatment time is 5 to 10 minutes at 25 to 30 ° C. Thereafter, washing with water is performed at room temperature for 1 to 3 minutes.

  Next, electroless plating is performed on the target surface to which the catalyst is attached to form an electroless plating film. The electroless plating is not particularly limited, but electroless copper plating, electroless nickel plating, electroless palladium plating, electroless silver plating, electroless gold plating, electroless platinum plating, etc. can be used. . Moreover, alloy plating of these noble metals can also be used. Of these platings, electroless nickel plating and electroless copper plating are preferred from the viewpoints of economy and workability.

  The electroless plating film may be a single layer, or two or more different layers may be formed. That is, it is preferable to appropriately adjust the film thickness and layer configuration of the electroless plating film in consideration of the required electromagnetic shielding characteristics, cost, and the like. The thickness of the electroless plating film is preferably 2 to 5 μm from the viewpoint of exhibiting sufficient electromagnetic shielding properties. Although depending on the type of plating, a desired electroless plating film can be obtained by treating a target electronic component for 20 to 60 minutes using a plating solution usually adjusted to 40 to 90 ° C. The pH of the plating solution is not particularly limited. For example, when an electroless nickel plating solution is used, 4.0 to 6.0 is preferable at room temperature (25 ° C.), and when an electroless copper plating solution is used. Is preferably 12.0 to 13.0 at room temperature.

  Further, an electrolytic plating film may be further formed on the electroless plating film in order to enhance the electromagnetic shielding effect. Although it does not specifically limit as electrolytic plating, Electrolytic copper plating, electrolytic nickel plating, electrolytic nickel alloy plating, electrolytic tin plating, electrolytic solder alloy plating, electrolytic zinc plating, electrolytic zinc alloy plating, electrolytic palladium plating, electrolytic palladium alloy plating, electrolytic Silver plating, electrolytic gold plating, etc. can be used. Of these plating methods, electrolytic nickel plating and electrolytic copper plating are preferable from the viewpoint of cost and economy.

  The electrolytic plating film may be only one layer, or two or more different layers may be formed. Similarly to the electroless plating film, it is preferable to appropriately adjust the film thickness and layer configuration of the electrolytic plating film in consideration of the required electromagnetic shielding characteristics, cost, and the like. In addition, when providing an electrolytic plating film, it is preferable that the film thickness is 5-10 micrometers. Although depending on the type of plating, a desired plating film can be obtained by treating a target electronic component for 15 to 30 minutes using a plating solution usually adjusted to 25 to 40 ° C.

  In addition, after the plating step, the protective film is removed to provide an electroless plating film that covers the surface excluding the part to which the protective film has been attached, and an electron with an electromagnetic shielding layer, optionally further provided with an electrolytic plating film. Parts can be obtained.

  As described above, for an electronic component having at least one semiconductor element and a sealing material covering the entire surface of the semiconductor element on the package substrate, an electromagnetic shield layer having high adhesion can be easily formed on the surface of the sealing material and the exposed surface of the package substrate. Can be formed. Electronic components manufactured by such a manufacturing method should be suitably mounted on electronic devices such as mobile phones, PCs, portable music players, televisions, white goods, printers, scanners, etc. and electronic devices mounted on automobiles. Is possible.

  Hereinafter, although the content of the present invention is explained in detail using an example and a comparative example, the present invention is not limited to the following examples.

[Example 1]
[Preparation process-protective film application process]
After mounting the semiconductor element on the package substrate by wire bonding, two types of electronic components were prepared by sealing the semiconductor element mounting package substrate with a sealing material. And the protective film was affixed with respect to the solder ball mounting surface of a package board | substrate. These electronic components had two types of structures as shown in FIGS. 1A and 1B (however, no plating film was formed at this stage). In addition, the material specifically used was as follows.
Package substrate: Single-sided BGA substrate (electroless Ni / Au plating finish)
Semiconductor element: Test semiconductor Protective film: manufactured by Hitachi Chemical Co., Ltd., plating protective film K-3940B
Sealing material: CEL-9700HF10, manufactured by Hitachi Chemical Co., Ltd.

[Plasma treatment process]
The two types of electronic components were fixed with a predetermined fixture, and the entire surface of the electronic components was subjected to plasma treatment. The plasma conditions were as follows.
Plasma processing apparatus: NEMS (Nano Electronics and Micro System Technologies. Inc.) vacuum plasma apparatus NEMST DS2008JP
Plasma method: Special plasma combining ICP (inductively coupled plasma) and HCP (hollow cathode plasma) Carrier gas: Mixed gas of oxygen, nitrogen and fluorine Processing pressure: 350 mTorr
Electric power: 8kW
Processing time: 40 minutes

[Plating process]
Next, electroless copper plating was performed on the plasma-treated electronic component. This is a general plating method used in printed wiring boards.

  First, alkaline degreasing was performed in order to remove dirt on the surface of the electronic component subjected to plasma treatment. Alkaline degreasing was performed by treating the target surface for 5 minutes using a cleaner conditioner CLC-601 (manufactured by Hitachi Chemical Co., Ltd.) adjusted to 60 ° C. After the alkaline degreasing, in order to remove the surfactant attached to the surface of the electronic component, it was further washed with warm pure water at 60 ° C. for 1 minute. Thereafter, it was further washed with pure water at room temperature for 3 minutes.

  Next, a pre-dip treatment was performed in order to prevent moisture on the surface of the electronic component from being brought into the catalyst solution. The pre-dip treatment was performed by treating the target surface for 1 minute using a pre-dip agent PD-301 (manufactured by Hitachi Chemical Co., Ltd.) adjusted to 25 ° C.

  Next, a palladium catalyst serving as a catalyst core for electroless plating was attached to the surface of the electronic component. The catalyst was attached by treating the target surface for 5 minutes using a sensitizer HS-202B (manufactured by Hitachi Chemical Co., Ltd.) adjusted to 25 ° C. Thereafter, the entire electronic component was washed with pure water at room temperature for 1 minute. In this example, adhesion promoting treatment was further performed in order to improve the plating precipitation by the palladium catalyst. The adhesion promotion treatment was performed by treating the target surface for 5 minutes using an adhesion promotion treatment agent ADP-601 (manufactured by Hitachi Chemical Co., Ltd.) adjusted to 25 ° C. After the adhesion promotion treatment, the entire electronic component was washed with pure water at room temperature for 1 minute.

Next, electroless copper plating was performed on the electronic component. The plating conditions were as follows. The plating film thickness was 2.5 μm in order to ensure electromagnetic shielding properties.
Electroless copper plating solution: CUST-3000 (manufactured by Hitachi Chemical Co., Ltd.)
Plating solution temperature: 70 ° C
Plating time: 1 hour Plating film thickness: 2.5 μm
pH: 12.5 (room temperature)

  After the plating treatment, the electronic component on which the electroless plating film was formed was washed with pure water at room temperature for 5 minutes and then dried at 80 ° C.

  As described above, two types of structures (electronic parts with a protective film on which a plating film was formed) as shown in FIGS. 1A and 1B were obtained.

[Example 2]
Two types of structures as shown in FIGS. 1A and 1B were obtained in the same manner as in Example 1 except that electroless nickel plating was performed instead of electroless copper plating. The plating conditions for electroless nickel plating were as follows.
Electroless nickel plating solution: NIPS-100 (manufactured by Hitachi Chemical Co., Ltd.)
Plating solution temperature: 85 ° C
Plating time: 20 minutes Plating film thickness: 3 μm
pH: 4.5 (room temperature)

[Comparative Example 1]
Electroless copper plating was performed on two types of electronic components in the same manner as in Example 1 except that the plasma treatment was not performed. However, plating swelling occurred on the surface of the sealing material in about 10 minutes after plating, and plating peeling occurred in about 30 minutes. Since an electroless plating film with high adhesion could not be formed on the sealing material, the electronic component was taken out of the plating solution at this point and the plating was stopped.

[Comparative Example 2]
Instead of the plasma treatment, electroless nickel plating was performed on the two types of electronic components in the same manner as in Example 2 except that the electronic components were treated using high-pressure CO _{2 in a} supercritical state. The treatment using high-pressure CO _{2 in a} supercritical state was performed as follows.

The supercritical high pressure CO _{2 in} which the palladium metal complex was dissolved was used to process the electronic component surface and attach the palladium catalyst. The processing conditions were as follows.
Equipment: Kyoshin Engineering Co., Ltd. SCC-109 type Palladium metal complex: Palladium chloride Treatment time: 30 minutes Medium: CO ₂
Temperature: 80 ° C
Pressure: 20MPa

As a result, penetration by supercritical high-pressure CO ₂ occurred between the sealing material and the package substrate. In addition, soaking and peeling occurred through the attached protective film, and a part of the protective film was dissolved.

The electronic component with the protective film in this state was washed with pure water at room temperature for 1 minute, and then electroless nickel plating was performed under the same conditions as in Example 2. However, as described above, in this example, since the treatment was performed using supercritical high pressure CO ₂ , pretreatment (alkali degreasing, pre-dip) was not performed. As a result, two types of structures as shown in FIGS. 1A and 1B could be obtained.

[Various evaluations regarding plating film]
For the two types of structures obtained in the examples and comparative examples, the following various evaluations on the electroless plating film were performed. The evaluation results are shown in Table 1.

[Appearance evaluation]
A case where plating peeling or swelling did not occur and the electroless plating film appearance was good was evaluated as A, and a case where plating peeling or swelling occurred and the electroless plating film appearance was not good was rated as B.

[Immersion evaluation]
When the protective film on the solder ball mounting surface is peeled off by hand, the plating solution may penetrate into the interface between the package substrate and the sealing material, or the plating solution may penetrate into the solder ball mounting surface through the protective film. I checked for it. The case where penetration did not occur was evaluated as A and the case where it occurred was evaluated as B.

[Adhesion evaluation]
In order to evaluate the adhesion between the sealing material and the electroless plating film, a test was conducted according to a cross-cut test method (JIS K-5400-8.5). The case where good adhesion was exhibited without peeling of the electroless plating film was evaluated as A, and the case where the electroless plating film was peeled was evaluated as B.

  As shown in Examples 1 and 2, according to the present invention, it was possible to form a magnetic shield layer on the surface of the sealing material with an electroless plating film having high adhesion and very good appearance.

  On the other hand, in Comparative Example 1 in which the plasma treatment was not performed, a good magnetic shield layer as in the example could not be formed.

In Comparative Example 2 using supercritical high-pressure CO ₂ instead of plasma treatment, it was possible to form an electromagnetic shielding layer with good adhesion, but the interface between the package substrate and the sealing material. In this case, a gap was generated, and the plating solution was seen to penetrate there. In addition, the protective film on the back surface of the package substrate partially melted and peeled off, and plating was deposited on the part, resulting in a short circuit, so that the performance as an electronic component could not be achieved.

  The manufacturing method of the present invention using plasma treatment and plating treatment can easily form a metal electromagnetic shield layer having good adhesion on the surface of the sealing material without greatly changing the assembly process of the semiconductor electronic component. Therefore, the assembly process is not complicated even when compared with the conventional metal cap method, and it is not necessary to use a metal cap, and thus it is possible to contribute widely to the reduction in size and thickness of electronic components. Moreover, in the method of this invention, since wastes, such as chromic acid and permanganic acid, are not taken out, it is useful also as a manufacturing method in consideration of the environment. Thus, the manufacturing method of the present invention is very useful in industry.

  DESCRIPTION OF SYMBOLS 10 ... Base material (package substrate), 20 ... Semiconductor element, 30 ... Sealing material, 40 ... Protective film, 50 ... Electroless plating film.

Claims (3)

Preparing a semiconductor element mounting substrate comprising a base material, a semiconductor element disposed on one surface of the base material, and a sealing material for sealing the semiconductor element;
Attaching a protective film to the other surface of the substrate;
Plasma treatment of the sealing material surface;
Forming an electroless plating film on the surface of the plasma-treated sealing material;
An electronic component manufacturing method comprising:   The plasma treatment is performed using a microwave plasma, a high-frequency plasma, an atmospheric pressure plasma, an inductively coupled plasma, a hollow cathode plasma, or a special plasma in which the inductively coupled plasma and the hollow cathode plasma are combined. Item 2. The manufacturing method according to Item 1.   An electronic component manufactured by the manufacturing method according to claim 1.

Images