JP2010127702A - Automatic detection method of metal powder foreign body in insulating resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detection method of metal powder foreign body capable of detecting and discriminating a metal powder foreign body having a maximum length of not less than 50 μm in an insulating resin, and capable of in-line arrangement. <P>SOLUTION: The automatic detection method of metal powder foreign body in the insulating resin composition is configured of a step of detecting the metal powder present in the insulating resin composition as a foreign body by changing the x-ray irradiating angle using an X-ray fluoroscope having at least one X-ray tube 2, 3, and a step of automatically performing an image recognition of the metal powder using an image processing device 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for detecting fine metal powder foreign matter in a resin composition that requires electrical insulation, and in particular, a method for detecting fine metal powder foreign matter in a resin composition used for insulating a semiconductor element in which fine wiring exists. It is about.

The method for detecting fine metal powder foreign matter in the resin is, in particular, fine metal powder used for resin sealing of semiconductors that cause short circuit defects, with silica powder as the main filler and epoxy as the main component resin for the binder. This is important in an epoxy molding material that is an organic-inorganic composite material using a resin.
A method for producing the epoxy molding material will be described.
First, the epoxy resin powder, filler powder, and other additive powders or liquids are mixed using a premixing device.
At this time, since the premixing device is usually made of metal and has a rotating portion made of metal, metal wear powder is mixed therein.
Next, this mixture is kneaded using a biaxial heating roll machine or a biaxial heating kneader and processed into a sheet.
Also at this time, since the kneading is performed using an apparatus having a rotating part made of metal, metal wear powder is mixed.
Subsequently, the heated kneaded sheet is cooled and pulverized by a pulverizer.
Also in this pulverization, since the pulverizer is made of metal and has a rotating part made of metal, metal powder is mixed by an impact force during pulverization.
Furthermore, when this pulverized powder is compressed into a cylindrical tablet using a metal device, metal wear powder is mixed here.
In order to prevent mixing of these metal powders, a magnetic metal foreign matter sorting and collecting device using magnetic force (see, for example, Patent Document 1) and a semiconductor sealing resin composition are placed in the magnetic flux, and there are metal foreign matters in the inspected body. In such a case, a metal foreign object detection method (for example, see Patent Document 2) is known in which a metal foreign object is inductively heated by magnetic flux to measure a temperature distribution.

However, a device using magnetic force cannot completely remove fine metallic foreign matter.
Further, the method of detecting a metal foreign object by measuring the temperature distribution by bringing the metal foreign object into an induction heating state by magnetic flux makes the apparatus large and cannot detect a fine metal foreign object completely.
Furthermore, a method of detecting foreign metal particles in an insulating resin using an X-ray fluoroscopic apparatus is generally performed as a nondestructive test.
In particular, when a microfocus X-ray apparatus having a focal size of an X-ray tube of several tens of μm or less is used, even a resin composition for sealing semiconductors containing silica powder as a main filler can detect metal powder foreign matter having a maximum length of several tens of μm can do.
However, if the focal spot size is reduced, the detection accuracy increases. However, since it is necessary to enlarge the X-ray fluoroscopic image, it takes time to search for and detect the metal powder foreign material, and it is used for inspecting the metal powder foreign material in-line. Was inappropriate.
When a microfocus X-ray apparatus is used, the detection time of one sample (hereinafter referred to as tact time) is about 30 to 300 seconds, although it varies depending on the size of the insulating resin sample and the metal powder foreign matter. Become.
In order to eliminate the disadvantage that the tact time becomes long, an X-ray apparatus using a CMOS (complementary metal oxide semiconductor) line sensor camera as a detector has been developed and marketed, and the tact time is about 0.2 to 1 second. However, it was difficult to detect a metal powder foreign material of about 200 μm or less with a resin composition for encapsulating a semiconductor containing silica powder as a main filler.
Furthermore, metal powder foreign matter generated by wear of metallic equipment is indeterminate (fibrous, foil, elliptical, etc.), so it is detected by its shape, the location of foreign matter, or the direction and angle of X-ray irradiation. There is a case where it can be detected and a case where it cannot be detected.

JP-A-9-173890 JP 2006-125937 A

  In the present invention, by using an X-ray fluoroscopy device, it is possible to detect and discriminate metal powder foreign matter having a maximum length of 50 μm or more present in an insulating resin, and in-line (epoxy resin molding material for semiconductor encapsulation) It is an object of the present invention to provide a metal powder foreign object detection method and apparatus capable of being incorporated in a manufacturing process.

  As a result of earnest research to achieve the above object, the present inventors have found that fine metal powder foreign matter can be reliably detected by changing the X-ray irradiation angle using an X-ray fluoroscope, and the present invention has been completed. It led to let me.

That is, the present invention
1. After detecting the metal powder existing as a foreign substance in the insulating resin composition by changing the X-ray irradiation angle using an X-ray fluoroscope having at least one X-ray tube, the image processing apparatus is used. A method for automatically detecting foreign particles of metal powder in an insulating resin composition, wherein the metal powder is automatically recognized as an image,
2. 2. The automatic detection method according to 1 above, wherein the insulating resin composition is a tablet made of an epoxy resin molding material for semiconductor encapsulation composed of an inorganic filler and an epoxy resin.
3. The automatic detection method according to 2 above, wherein the tablet is cylindrical,
4). The automatic detection method according to 3 above, wherein the metal powder existing as a foreign substance is detected twice by changing the X-ray irradiation angle from the side surface of the cylindrical tablet,
5). The automatic detection method according to 4 above, wherein the defect of the cylindrical tablet is determined simultaneously with the image recognition of the metal powder foreign matter,
6). The automatic detection method according to 4 or 5 above, wherein the maximum length of the metal powder foreign matter is 50 μm or more,
7). The automatic detection method according to any one of 1 to 6, incorporated in an epoxy resin molding material manufacturing process for semiconductor encapsulation,
8). An automatic detection device comprising an X-ray fluoroscopic device and an image processing device that can be incorporated into a manufacturing process of an epoxy resin molding material for semiconductor encapsulation, using the automatic detection method according to any one of 1 to 6 above. is there.

According to the metal powder foreign matter detection method of the present invention, a fine metal powder foreign matter having a maximum length of 50 μm or more present in an insulating resin that could not be detected by the conventional inline method can be detected and discriminated.
Therefore, when used for inspection of insulating resin made of semiconductor encapsulating material, in-line inspection can be performed by in-line method instead of conventional sampling inspection. A highly reliable insulating resin for a semiconductor device free from foreign metal powder can be obtained, and a semiconductor device using the insulating resin has high reliability.

Hereinafter, the present invention will be described in detail.
In the present invention, after detecting the metal powder present as a foreign substance in the insulating resin composition by changing the X-ray irradiation angle using an X-ray fluoroscope having at least one X-ray tube, The present invention relates to a method for automatically detecting a metal powder foreign matter in an insulating resin composition that automatically recognizes an image of the metal powder using a processing apparatus.
In the present invention, X-rays transmitted through a sample (insulating resin composition) are imaged after being amplified by a detector.
The video signal is digitally converted by image capture, and then the image is stored.
In the image processing apparatus, image processing such as image integration and correction is performed in order to improve the digitally converted image.
The processed image is converted into an analog image and displayed on the monitor.
When the metal powder foreign matter in the sample is recognized as an image, the sample is automatically determined as a defective product and can be removed out of the system.

In the present invention, the position, orientation, irradiation angle and the number of X-ray tubes and detectors are not particularly limited.
For example, by using a plurality of X-ray tubes and a plurality of detectors, it is possible to detect metal powder foreign matter in a sample at a time.
In addition, the X-ray tube and the detector are each set as one, and by rotating the sample, the X-ray irradiation angle is changed to detect foreign metal particles in the sample, or the X-ray tube and the detector are It is also possible to detect the metal powder foreign matter in the sample by changing the X-ray irradiation angle by making it movable.

Although there is no restriction | limiting in particular in the form of the sample of this invention, Preferably it is a tablet, More preferably, it is cylindrical shape.
In this invention, when a sample is a cylindrical tablet, the automatic detection method which detects the metal powder which exists as a foreign material twice by changing an X-ray irradiation angle from the side surface of a sample is preferable.
In this case, simultaneously with the image recognition of the metal powder foreign matter, it is possible to simultaneously determine the defects of the cylindrical tablet (such as cracks, cracks, and nests).
The maximum length of metal powder foreign matter that can be detected is 50 μm or more.
According to the detection method of the present invention, the tact time (detection time) of one sample is usually 1 to 3 seconds, although it varies depending on the size of the sample.
The automatic detection method and apparatus of the present invention can be incorporated in a manufacturing process of an epoxy resin molding material for semiconductor encapsulation.

A commercially available product can be used as the X-ray tube used in the present invention, and there is no particular limitation. However, the tube voltage is 30 to 100 kV, the tube current is 0.1 to 1.0 mA, and the minimum focal size is 0. A 1 mm X-ray tube is preferred.
A commercially available product can be used as the detector, and there is no particular limitation, but the detector is a combination of an X-ray image intensifier (X-ray II) and a CCD (charge coupled device) camera, an X-ray image input. A combination of a tensiifier (X-ray II) and a flat panel detector is preferred.
If high detection accuracy is not required, a CCD line sensor camera can be used.
As the image processing apparatus, a commercially available product can be used as long as it can perform image integration, image averaging, edge processing, brightness adjustment, measurement function, and image storage, and there is no particular limitation.

Next, the present invention will be described in detail with reference to FIG.
FIG. 1 shows an embodiment of an automatic detection method for metal powder foreign matter in the insulating resin composition of the present invention.
The left side of FIG. 1 shows an in-line X-ray fluoroscopy device comprising X-ray tube 2, X-ray tube 3, detector 4, and detector 5. The X-ray irradiation angle of the tube is 90 °.
In the case of an in-line apparatus, the sample (insulating resin composition) 1 is aligned and transported by, for example, a conveyor 6, and X-rays transmitted through the sample 1 are imaged after being amplified by a detector.
The video signal is digitally converted by the image capture 7 and then the image is stored.
In the image processing apparatus 8, image processing such as image integration and correction is performed in order to improve the digitally converted image.
The processed image is converted into an analog image and displayed on the monitor 11 as an image.
When the metal powder foreign matter in the sample 1 is image-recognized, it is automatically determined that the sample 1 is a defective product and is removed from the semiconductor sealing epoxy resin molding material manufacturing process system via the interface 10.
Reference numeral 9 denotes a central processing unit (CPU).

Next, the insulating resin composition of the present invention will be described.
The automatic detection method of the present invention can be applied to any resin composition as long as the insulating resin composition is insulative, but is preferably an epoxy resin molding material for semiconductor encapsulation.
The epoxy resin molding material for semiconductor encapsulation is obtained from, for example, (A) an epoxy resin, (B) a phenol resin curing agent, (C) a curing accelerator and (D) an inorganic filler. It is formed into a shape.

(A) As an epoxy resin, as long as it has two or more epoxy groups in one molecule, there is no limitation on the molecular structure, molecular weight, etc., and those generally used for sealing semiconductor elements should be used. Can do.
Specific examples include a cresol novolac type epoxy resin, a dicyclopentadiene type epoxy resin, a biphenyl type epoxy resin, a biphenyl novolac type epoxy resin, a polyfunctional type epoxy resin, and a naphthalene skeleton-containing upoxy resin.
An epoxy resin may be used individually by 1 type, and may use 2 or more types together.
Moreover, as an epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, these brominated epoxy resins, etc. can be used together.

(B) The phenol resin curing agent can be used without limitation as long as it has two or more phenolic hydroxyl groups in one molecule and can be cured by reacting with the epoxy group in the epoxy resin of component (A). However, from the viewpoint of moisture resistance reliability, it is preferable to use the following.
That is, a phenol novolak resin, a cresol novolak resin, a dicyclopentagen-modified phenol resin, a phenol aralkyl resin, a polyfunctional phenol resin, and the like can be given.
A phenol resin hardening | curing agent may be used individually by 1 type, or may use 2 or more types together.
Moreover, a phenol resin such as a naphthol aralkyl resin can be used in combination as a phenol resin curing agent.

The (C) curing accelerator mainly promotes the reaction between the (A) epoxy resin and the (B) phenol resin curing agent.
Although there is no restriction | limiting in particular as a hardening accelerator, The thing with a low impurity concentration is preferable.
Specifically, trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, tri (p-methylphenyl) phosphine, tri (nonylphenyl) phosphine, methyldiphenylphosphine, dibutylphenylphosphine, tricyclohexylphosphine, bis (diphenyl) Organophosphorous curing accelerators such as phosphino) methane, 1,2-bis (diphenylphosphino) ethane, tetraphenylphosphonium tetraphenylborate, triphenylphosphinetetraphenylborate, triphenylphosphinetriphenylborane, 1,8 A curing accelerator based on a diazabicycloalkene compound such as diazabicyclo [5,4,0] undecene-7 (DBU) or 1,5-diazabicyclo (4,3,0) nonene-5, Tadecylimidazole, 2-methylimidazole, 2-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 4-methylimidazole, 4-ethylimidazole, 2-phenyl-4-hydroxymethylimidazole, 2- Imidazole-based curing accelerators such as ethyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, etc. Can be mentioned.
A hardening accelerator may be used individually by 1 type, and may use 2 or more types together.
The blending ratio of the curing accelerator is usually 0.01 to 5% by mass with respect to the entire epoxy resin molding material (epoxy resin composition).
When the blending ratio is less than 0.01% by mass, the gel time of the epoxy resin composition becomes long and the production cycle of the resin-encapsulated semiconductor device becomes long.
On the other hand, if it exceeds 5% by mass, the fluidity of the epoxy resin composition is significantly lowered, so that the filling property is deteriorated, and the moisture resistance reliability of the cured product after sealing is also lowered.

(D) As the inorganic filler, fused silica, crystalline silica, alumina, zirconia, talc, clay, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, titanium white, bengara, silicon carbide, boron nitride, silicon nitride, Examples thereof include powders such as aluminum nitride, beads obtained by spheroidizing these, single crystal fibers, and glass fibers.
Of these, powders of fused silica, crystalline silica, and alumina having a low impurity concentration are preferable.
Also, those having a maximum particle size smaller than the pin interval of a semiconductor package or the like are preferable, and those having a maximum particle size of 50 μm or less are usually used.
An inorganic filler may be used individually by 1 type, and may use 2 or more types together.
70-95 mass% is preferable with respect to the whole epoxy resin composition, and, as for the mixture ratio of an inorganic filler, 80-92 mass% is more preferable.
When the blending ratio is less than 70% by mass, the moisture resistance reliability of the cured product after sealing is lowered, and when it exceeds 95% by mass, the fluidity of the epoxy resin composition is lowered and the filling property becomes poor.

The epoxy resin composition for semiconductor encapsulation contains (A) an epoxy resin, (B) a phenol resin curing agent, (C) a curing accelerator and (D) an inorganic filler as essential components, but does not inhibit the sealing effect. As long as necessary, release agents such as coupling agents, natural waxes, synthetic waxes, linear aliphatic metal salts, acid amides and esters, rubber-based and silicone-based polymers, which are generally blended as necessary Such a low stress imparting agent can be further blended.
Moreover, coloring agents other than carbon black, such as cobalt blue, can also be mix | blended suitably.

  Coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacryloxypropyl) tri Methoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) ) -Γ-aminopropylmethyldiethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3 -Triethoxysilylpro E) Silane coupling agents such as tetrasulfane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, imidazolesilane, etc., but also titanium coupling agents and aluminum alcoholates Etc. can also be used.

The epoxy resin composition for semiconductor encapsulation comprises (A) an epoxy resin, (B) a phenol resin curing agent, (C) a curing accelerator and (D) an inorganic filler, and the above-described various components blended as necessary. The mixture is uniformly mixed by a mixer, and further heated and melted and kneaded by a hot roll or a kneader, then cooled and solidified, and then pulverized to an appropriate size.
By putting this pulverized powder in a mold and compressing it with a press, a tablet of an epoxy resin composition for semiconductor encapsulation can be produced.

Examples 1 and 2, Comparative Examples 1-5
Spherical fused silica (average particle size 20 μm) 87.4% by mass, orthocresol novolak epoxy resin (manufactured by Sumitomo Chemical Co., Ltd., trade name ESCH195XL), 7.15% by mass, phenol novolac resin (manufactured by Showa Polymer Co., Ltd., trade name) BRG-556) After mixing 5.0 mass%, triphenylphosphine 0.15 mass%, carbon black 0.3 mass%, and carbana wax 0.2 mass%, they are kneaded with a heating roll at 60 to 130 ° C. Thereafter, cooling and pulverization were performed to prepare an epoxy resin composition for semiconductor encapsulation.
Next, after mixing metal wear powder (SUS304), which is a foreign substance whose maximum length has been measured in advance, a cylindrical tablet (diameter 14 mm, height 20 mm) is made as a sample, and an X-ray fluoroscope comprising various detectors is prepared. Used, a metal powder foreign matter detection test was performed.
The results are shown in Table 1.
The numbers in the table indicate (number of sample tablets detected by X-ray) / (total number of sample tablets), and the tact time indicates the detection time of metal powder foreign matter in one sample.

Further, in the production of the above-mentioned cylindrical tablet (diameter 14 mm, height 20 mm) sample, a defect detection test was similarly performed on a sample in which a chip having a maximum diameter of 0.5 to 2.0 mm was generated.
The results are shown in Table 2.
The numbers in the table indicate (number of defective sample tablets detected by X-ray or visual observation) / (total number of defective sample tablets).

  According to the metal powder foreign matter detection method of the present invention, it is possible to detect and discriminate fine metal powder foreign matter having a maximum length of 50 μm or more present in the insulating resin that could not be detected by the conventional inline method. The in-line method can be used instead of the conventional sampling inspection, and 100% inspection and 100% guarantee are possible, and a product with excellent reliability can be obtained.

An embodiment of an automatic detection method for metal powder foreign matter in an insulating resin is shown.

Explanation of symbols

1 Sample 2, 3 X-ray tube 4, 5 Detector 6 Conveyor 7 Image capture 8 Image processing device 9 Central processing unit (CPU)
10 Interface 11 Monitor

Claims (8)

  After detecting the metal powder existing as a foreign substance in the insulating resin composition by changing the X-ray irradiation angle using an X-ray fluoroscope having at least one X-ray tube, the image processing apparatus is used. And automatically recognizing the image of the metal powder, and a method for automatically detecting a metal powder foreign matter in the insulating resin composition.   The automatic detection method according to claim 1, wherein the insulating resin composition is a tablet made of an epoxy resin molding material for semiconductor encapsulation composed of an inorganic filler and an epoxy resin.   The automatic detection method according to claim 2, wherein the tablet is cylindrical.   The automatic detection method of Claim 3 which detects the metal powder which exists as a foreign material twice by changing an X-ray irradiation angle from the side surface of a cylindrical tablet.   The automatic detection method of Claim 4 which determines the defect of a cylindrical tablet simultaneously with the image recognition of a metal powder foreign material.   The automatic detection method according to claim 4 or 5, wherein the maximum length of the metal powder foreign matter is 50 µm or more.   The automatic detection method according to claim 1, which is incorporated in a process for producing an epoxy resin molding material for semiconductor encapsulation.   An automatic detection apparatus comprising an X-ray fluoroscopic apparatus and an image processing apparatus that can be incorporated into a manufacturing process of an epoxy resin molding material for semiconductor encapsulation, using the automatic detection method according to claim 1.

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