JP2001351932A - Resin structure and method for laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure and method by which selective laser beam machining of at least one layer of a resin mold composed of a plurality of layers is enabled, by increasing a sensitivity of the sealing resin or giving a light-extinguishing function to a solder resist layer. SOLUTION: The resin structure for laser beam machining is composed of a plurality of layers 2, 5, and 6, and at lest one 2 of the layers 2, 5, and 6 has sensitivity increase function to a laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin structure used for mounting electronic devices and a method for processing the same.

[0002]

2. Description of the Related Art With the rapid development of electronic devices in recent years, L
There has been a demand for higher integration of SI. In order to meet such needs of the times, the density of wiring boards has been increasing at an accelerating rate. With the increase in the degree of integration of such electronic devices, many very expensive wiring boards and semiconductor elements have appeared, and there has been a growing demand for an improvement in the yield of wiring boards.

[0003] In the mounting of semiconductor elements or integrated circuit elements used in current electronic equipment, those using a sealant for increasing reliability are increasing. The material used for sealing has a very high airtightness to improve vibration resistance, dust resistance, water resistance, and thermal shock resistance, and various materials such as ceramics, metal materials, resin materials, etc.・ It has been devised. Sealing using a ceramic or metal material has high reliability but high cost, and is inferior in workability as compared with sealing using a resin material. Therefore, resin sealing is now common.

[0004] Materials used for resin encapsulation include epoxy resin, silicone resin, phenol resin, diallyl phthalate resin, polyimide resin, etc., but are excellent in heat resistance, moisture resistance, chemical resistance, adhesiveness and the like. Epoxy resins are widely used. Although the sealing resin can ensure high mounting reliability due to its high adhesive strength, it is very difficult to remove the resin once it has been subjected to heat treatment to cure the resin. Alternatively, there is a problem that it is difficult to remove the semiconductor element when a failure occurs in the wiring board.

There are three main types of encapsulation using a resin, a glob top type (FIG. 2), a mold type (FIG. 3), and an underfill type (FIG. 4). The glob top type and the mold type are sealing forms mainly used at the time of wire bonding connection, and are forms in which the semiconductor element itself is cured while being surrounded by a sealing resin. The underfill type is a sealing mode mainly used for flip chip connection, in which a sealing resin is poured only into a connection portion between a semiconductor element and a wiring board, and the poured resin is cured.

[0006] There are two types of substrates on which semiconductor elements are mounted, mainly those using ceramics and those using organic materials. Many high-density wiring boards have a laminated structure called build-up, as shown in FIG. The build-up wiring board has two parts, a core layer and a build-up layer. The core layer plays a role as a structural support of the wiring board and a layer with a low wiring density such as a power supply layer, so that the high-density wiring layer is used at a low density to balance the wiring density. I have.

[0007] Organic substrate materials that are advantageous in that they can draw narrow-pitch wiring include acrylic, polyolefin, polyurethane, polycarbonate, polystyrene, polyether, polyamide, polyimide, polymers containing fluorine, polyester, phenolic resin, and fluorene. resin,
Although there are various materials such as benzocyclobutene and silicon-based polymers, epoxy resins excellent in cost, low thermal expansion, low dielectric loss, heat resistance and the like are generally used. The outermost layer of the wiring board is coated with a solder resist for preventing solder flow. Many of these solder resists are also epoxy resins like the substrate material and the sealing resin, and it can be said that current organic wiring boards are formed of epoxy resins.

Next, a description will be given of a conventional technique for removing a semiconductor element when a defect occurs on the semiconductor element or the wiring board side. As an example of a method of removing a defective element sealed with a resin, a method of removing a semiconductor element by applying heat to weaken the adhesive strength of the resin and removing the residual resin using a solvent (for example, Japanese Patent Application Laid-Open No. H11-130946). Gazette, JP-A-10-095833, JP-A-11-23
No. 3571) have been proposed.

However, this method has the disadvantage that the time required to remove the resin residue is generally long, and it is difficult to completely remove the resin residue. Further, since most of the sealing resin and the wiring board currently used are both epoxy resins, there is a possibility that the wiring board side may be damaged by a solvent for removing the resin residue. Furthermore, the state of the wiring board surface changes due to the solvent for removing the resin residue,
When the wiring substrate is reused, there is a possibility that the refillability of the sealing resin may be deteriorated. When a solvent is used as described above, it is difficult to selectively process only the sealing resin without affecting the wiring substrate side.

Due to the above-mentioned concerns, there has been devised a method of making the mounted body itself a reusable structure in case of failure. As an example of this, a method has been proposed in which an interposer structure is formed when a semiconductor element is mounted, and when a defect occurs, the entire interposer is removed by solder reflow (Japanese Patent Application Laid-Open No. 04-124845).

However, the mounting method using the interposer is disadvantageous for high-speed signal transmission and has a drawback that it is difficult to achieve impedance matching. For this reason, repairing a semiconductor device by taking an interposer structure is not sufficient as a means for solving a fundamental problem.

As a method of removing a sealing resin which does not require a solvent or heat, a method of irradiating an electromagnetic wave to the resin residue (Japanese Patent Laid-Open No. 6-77264), a method of removing a wiring board through which a laser beam is transmitted. Used during mounting, irradiate laser light from the back surface where the semiconductor element is mounted,
Method for weakening adhesion of sealing resin (JP-A-4-25724)
No. 0) has been proposed.

However, since most of the encapsulation resins and wiring boards currently used are both epoxy resins, it is difficult to selectively process only the encapsulation resin, and it is difficult to remove the encapsulation resin. When laser irradiation is performed at a laser intensity of the above, there is a possibility that the sealing resin refillability when the wiring substrate is reused may be deteriorated due to damage to the wiring substrate and changes in the surface state of the wiring substrate. It is difficult. Further, most of the wiring boards currently used do not have laser transmittance, and it is difficult to solve the problem by the method disclosed in Japanese Patent Application Laid-Open No. 4-257240.

[0014]

As described above, the prior art does not disclose any material, structure and method for selectively processing only the sealing resin.

In general, to remove the sealing resin, a method is used in which a solvent having a solubility parameter close to that of the sealing resin is used to swell or dissolve the resin to lower the adhesion of the resin.

However, both the wiring board and the sealing resin currently used as mounting materials are often made of epoxy resin, and when a solvent is used, selective processing of only the sealing resin or only the wiring board is not possible. Have difficulty.

The same problems as described above apply to the processing of the sealing resin using a laser, and it is difficult to selectively process only the sealing resin or only the wiring substrate.

An object of the present invention is to provide a resin material comprising a plurality of layers as shown in FIG.
Another object of the present invention is to provide a structure capable of selectively processing at least one layer by giving a quenching effect to a solder resist layer, and a processing method thereof.

[0019]

SUMMARY OF THE INVENTION The present invention basically employs the following technical configuration to achieve the above object.

That is, a first embodiment of the resin structure for laser processing according to the present invention is a resin structure for laser processing comprising a plurality of layers, wherein at least one of the plurality of layers has
A layer having a sensitizing effect on laser light, and a second aspect is a resin structure for laser processing composed of a plurality of layers, wherein At least one layer is characterized by being a layer in which a compound having a sensitizing effect on laser light is dispersed, and a third embodiment is a laser processing resin structure comprising a plurality of layers. Further, at least one of the plurality of layers is a layer having a quenching effect on laser light, and the fourth aspect is a laser processing resin comprising a plurality of layers. The structure, wherein at least one of the plurality of layers is a layer in which a compound having a quenching effect on laser light is dispersed, and a fifth embodiment is characterized in that: A layer having a quenching effect on laser light, or The layer in which a compound having a quenching effect on laser light is dispersed is a substrate on which a semiconductor is assembled. In a sixth aspect, the plurality of layers are formed by sealing a semiconductor. A layer having a quenching effect on the laser light, or a layer in which a compound having a quenching effect on the laser light is dispersed, is a lowermost layer of the sealing material. And a seventh aspect is characterized in that the plurality of layers are sealing materials for sealing a semiconductor,
In an eighth aspect, at least one of the plurality of layers is a sealing material for sealing a semiconductor.

In a first aspect of the method for processing a resin structure according to the present invention, the resin structure comprising a plurality of layers is irradiated with a laser beam to selectively remove at least one of the plurality of layers. The second aspect is characterized in that
The layer to be selectively removed contains a sensitizer in an effective absorption wavelength range corresponding to the wavelength of the laser beam. At least one of the layers includes a layer in which a quencher is dispersed,
The layer in which the quencher is dispersed is not processed by the laser light. The fourth mode is that the laser light is irradiated from the surface of the semiconductor element and the laser light that has passed through the semiconductor element. And selectively processing only the resin material on the lower surface of the semiconductor element, and the fifth mode is to irradiate an infrared laser from the surface side of the semiconductor element,
Processing the resin material on the lower surface of the semiconductor element with an infrared laser that has passed through the semiconductor element, removing the semiconductor element from the wiring board, and then removing the residual resin, and The sixth mode is characterized in that a cavity structure is formed by irradiating a resin material composed of a plurality of layers with a laser beam and selectively removing each layer in order from a surface layer. The aspect is characterized in that each layer to be selectively removed contains a sensitizer of a different effective absorption wavelength range, and each layer is selectively processed with laser light having a wavelength corresponding to the effective absorption wavelength range. Is what you do.

As described above, the present invention relates to a material in which a resin has a structure having a sensitizing portion corresponding to a laser light wavelength region, or a resin having a sensitizing portion corresponding to a laser light wavelength region. The problem can be solved by the material obtained by dispersing.

Further, for the parts not desired to be processed,
The selective processing can be performed by a material obtained by dispersing a compound having a quenching portion corresponding to a laser light wavelength region or the like into a material having a structure having a quenching portion or a resin.

Either one or both of the above-described resins capable of selective processing by sensitization or the resins capable of selective processing by quenching may be used.

The resin capable of being selectively processed by a laser, or the sensitizer or quencher to be dispersed used in the present invention may be either an organic dye or an inorganic dye, but adversely affects the mounting reliability of the sealing resin. It is necessary to add an amount that does not affect the process, and it is desirable to have a heat resistance that can withstand various assembly processes, for example, a heat resistance that can withstand a process of a commonly used eutectic solder at a reflow temperature of 230 ° C. Those having properties are desirable.

It is desirable that the amount of the sensitizer to be added to the resin that enables selective processing by dispersing the sensitizer is as small as possible from the viewpoint of avoiding a decrease in mounting reliability and reducing costs. Therefore, those having a large molecular extinction coefficient are suitable, and specifically, it is desirable that the molecular absorption coefficient be 10,000 or more. It can be used even if the molecular extinction coefficient is smaller than 10,000, but in that case, the amount of sensitizer to be added increases, which is disadvantageous in terms of mounting reliability and cost, so that the usage application is limited. Will be done.

It is necessary that the sensitizer added to the resin that enables selective processing by dispersing the sensitizer does not lower the mounting reliability. Therefore, those having low hygroscopicity and high melting point are desirable. Specifically, a diimonium-based compound,
Organic compounds such as cyanine compounds, aminium compounds, anthraquinone compounds, and polymethylene compounds,
Inorganic compounds such as chromium oxide and manganese dioxide;

In the present invention, a laser beam used for selective processing is a solid laser, a gas laser, a semiconductor laser,
Any of a dye laser, an excimer laser, a free electron laser, and the like can be used, and any resin or material having a portion suitable for the wavelength can be used. A commercially available carbon dioxide laser, ND: YA
G lasers, ND: YAF lasers, and lasers using harmonics thereof can be used. However, when performing selective processing that requires precision so as not to damage the underlayer at all, a laser having a very large energy is not suitable. Therefore, a laser having an oscillation wavelength of 300 nm or more is desirable as a wavelength region having energy capable of fine processing, and more preferably, an infrared region to an ultraviolet region,
Specifically, it is desirable to use a laser having an oscillation wavelength of 300 nm or more.

An example of the proper use of the laser according to the application will be described below. Since the ultraviolet laser has a large photon energy, the processing of the resin is ablation. Therefore, adhesion of resin residue powder or the like is not observed on the processed surface, and very fine processing can be performed. On the other hand, an infrared laser has a small photon energy, and in order to perform processing similar to that of an ultraviolet laser, a device such as a short pulse is required. With such features, underfill-type sealing resin processing can be performed even when the silicon chip is mounted on the wiring board with little damage to the wiring board. Visible lasers have intermediate properties between ultraviolet and infrared lasers. Of the organic dye sensitizers used in the present invention, most of those having a small molecular weight and excellent dispersibility have a sensitized region in the visible region, so that any of the above two application examples is possible.

In the case where a sensitizer is dispersed in a sealing resin or a substrate material and selective processing is enabled by irradiating an infrared laser, an azurenium compound, an aminium compound, an anthraquinone compound, a croconium compound can be used. Dyes such as compounds, cyanine compounds, diimonium compounds, squarium compounds, naphthoquinone compounds, pyrylium compounds, phthalocyanine compounds, polymethylene compounds, polymethylene compounds, and merocyanine compounds can be used, but are not limited thereto. It is not something to be done.

The quenching agent dispersed in order to reduce the etching rate at the time of laser processing, like the sensitizer, must not lower the mounting reliability. The quenching is a compound that, while the compound itself hardly absorbs light, efficiently captures active free radicals generated by the light and suppresses a photoreaction. Specific examples of the quenching agent that can be used in the present invention include an organic nickel compound.
2'-thiobis (4-tertiary octylphenolate)]-
2-ethylhexylamine-nickel (II), nickel dibutyl-dithiocarbamate, [2.2′-thiobis (4-tertiary octylphenolate)]-n-butylamine-nickel (II), nickel bis (octylphenyl) ) Sulfide, nickel complex 3,5
-Di-tert-butyl-4-hydroxybenzylic amide monoethylate, 2.2'-thiobis (4-tert-octylphenolate) triethanolamine-nickel (I
I) and the like, but any of these may be used and is not limited thereto.

The resin to which the sensitizer is added is generally an epoxy resin. Polyolefin, polyurethane, polycarbonate, polyether, polyamide, a polymer containing fluorine, polyester, fluorene resin, benzocyclobutene, phenol resin, and silicone resin Any material such as a polymer may be used, and the material is not limited thereto.

[0033]

Most of the materials currently used for substrate materials are epoxy resins. Materials such as copper foil, polyimide, glass cloth, and the like are used for the internal layer of the high-density wiring board built up of this material. However, the top layer has a solder resist layer for the purpose of preventing solder flow,
This solder resist layer is often an epoxy resin like the wiring board. In addition, a resin that seals between the semiconductor element and the wiring board generally uses an epoxy resin in many cases. Since the above-described materials are used, when a defect occurs on the semiconductor element or the wiring board side, even if the semiconductor element can be removed by heat or the like, the sealing resin is removed by a solvent or the like. Attempts have often caused damage to the wiring board side. Therefore, in the present invention, a resin for selectively sensitizing or quenching a laser is dispersed in one or both of a sealing resin and a wiring board, or a resin element itself is provided with such a portion to replace a defective element. Enable
Only a desired portion can be selectively processed.
Further, as an application example of the present invention, a material composed of a plurality of layers as shown in FIG. 6 is irradiated with an infrared laser, a visible laser, and an ultraviolet laser sequentially (FIGS. 7, 8, and 9). It is also possible to form a fine cavity structure using a laser.

[0034]

EXAMPLES The present invention will be described more specifically below, but the present invention is not limited to the following examples unless it exceeds the gist.

In the following, the semiconductor element is mounted on the wiring board, but a defect occurs on the semiconductor element or the wiring board side,
An example in which a semiconductor element and a sealing resin are removed from a wiring substrate without damaging the wiring substrate will be described. When an infrared laser is used, the resin is decomposed or melted and vaporized via a thermal reaction. An ultraviolet laser or a visible laser may be used, but as the laser oscillation wavelength becomes shorter, ablation is mainly used for resin processing. Although there is a difference in the processing shape, since there is a difference in the etching rate, selective processing is possible using any laser. However, ultraviolet lasers and visible lasers have a high possibility of damaging the wiring board side due to large photon energy. Therefore, it is the infrared laser that can maximize the etching rate in performing the selective processing.

Further, since the infrared laser passes through the silicon, by performing infrared laser irradiation from the semiconductor element side, it is possible to process the sealing resin with the semiconductor element attached. Therefore, it can be more suitably used as compared with lasers in other wavelength ranges.

In one embodiment of the present invention, a sensitizer or a quencher is dispersed in a resin capable of being selectively processed by a laser. In that case, in order not to deteriorate the heat resistance of the material to be processed, it is desirable that the compound to be dispersed has high heat resistance.

For example, when the present invention is applied to a sealing material, a solder reflow process is performed. Therefore, the sensitizer or quencher to be dispersed, the compound having the sensitizing effect, and the compound having the quenching effect are required not to be altered by heat. Specifically, it is necessary to have a heat resistance of 100 ° C. or more, and more preferably to endure the reflow temperature of a commonly used tin-lead eutectic solder. Is desirable.

Example 1 Sensitizer of diimonium-based compound (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range 800 to 1200 nm, molecular extinction coefficient 1040)
00, m. p. About 250 ° C) for 1W to epoxy sealing resin
After applying the material 2 dispersed in t% to the wiring substrate 6 with a thickness of 110 μm, a curing treatment of the sealing resin was performed. Subsequently, laser irradiation was performed using a ND: YAG laser beam machine from the side of the sealing resin under the conditions of a wavelength of 1064 nm and 0.1 mj / pulse. Observation of the laser-irradiated surface using an SEM confirmed that the solder resist layer 5 was not damaged and that only the sealing resin material 2 to which the sensitizer was added was selectively processed.

Example 2 IRG-040 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range 800 to 1200 nm, molecular extinction coefficient 10)
4000, m. p. (About 250 ° C.) was added at 1 Wt% to prepare a resin material 2 dispersed therein.

This is underfilled into the semiconductor element 1 mounted on the epoxy wiring board 6 as shown in FIG.
After curing the sealing resin material 2 by performing a heat treatment, as shown in FIG. 10, after the semiconductor element is mechanically removed, the sealing resin remaining on the wiring board 6 is ND:
Wavelength 1 from the side of the sealing resin 2 using a YAG laser processing machine
Laser irradiation was performed under the conditions of 064 nm and 0.1 mj / pulse (FIG. 11). From the observation result of the laser irradiation surface using the SEM, it was confirmed that only the sealing resin material residue 20 could be selectively processed without damaging the solder resist layer 5 (FIG. 12).

Example 3 IRG-040 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range 800 to 1200 nm, molecular extinction coefficient 10)
4000, m. p. (About 250 ° C.) was added in an amount of 0.1 Wt% to prepare a dispersed resin material 2. This is underfilled into the semiconductor element 1 mounted on the epoxy wiring board 6 as shown in FIG. 1, and the heat treatment is performed to cure the sealing resin material 2, and thereafter, as shown in FIG.
After the semiconductor element 1 is mechanically removed, the sealing resin material 2 remaining on the wiring board is subjected to a wavelength of 1064 nm from the side of the sealing resin material 2 using an ND: YAG laser beam machine.
By performing laser irradiation under the condition of 0.1 mj / pulse, most of the sealing resin residue 20 could be removed. Since the amount of the sensitizer added was small, a small amount of the sealing resin residue 20 remained on the wiring board 6, but as shown in FIG. 13, the hot plate 21 heated the wiring board 6 to 80 ° C.
Then, as shown in FIG. 11, all the residual resin could be removed by using a cotton swab 22 soaked in a solvent (FIG. 12). From the observation result of the laser irradiation surface using the SEM, it was confirmed that only the sealing resin residue 20 could be selectively processed without damaging the solder resist layer 5.

Example 4 IRG-040 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range 800 to 1200 nm, molecular extinction coefficient 10)
4000, m. p. (About 250 ° C.) was added at 1 Wt% to prepare a resin material 2 dispersed therein. The semiconductor element 1 mounted on the epoxy wiring board 6 as shown in FIG.
The sealing resin was cured by performing an underfill and performing a heat treatment. With the semiconductor element 1 still mounted, laser irradiation was performed from the side of the semiconductor element with a wavelength of 1064 nm and 0.3 mj / pulse using an ND: YAG laser processing machine. As a result, the adhesive force of the sealing resin could be reduced by the laser transmitted through the semiconductor element 1 (FIG. 15). Subsequently, by heating to the solder reflow temperature from the wiring board 1 side, the semiconductor element 1 could be easily removed as shown in FIG. By irradiating infrared laser again to the sealing resin residue 20 remaining on the wiring substrate, the wiring substrate 6 could be brought into the same state as before the application of the sealing resin (FIG. 17). From the observation result of the laser irradiation surface using the SEM, it was confirmed that only the sealing resin residue 20 could be selectively processed without damaging the solder resist 5.

Example 5 UV-378 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range of 325 to 410 nm, molecular extinction coefficient of 3080) was used as the epoxy sealing resin.
0, m. p. (About 260 ° C.) was added at 1 wt% to prepare a dispersed resin material 2. This is shown in FIG.
The semiconductor element 1 mounted on the epoxy wiring board was underfilled and heat-treated to cure the sealing resin. Thereafter, as shown in FIG. 10, after the semiconductor element was mechanically removed, as shown in FIG. 11, the third harmonic of the ND: YAG laser was used for the sealing resin remaining on the wiring board. Using an IHG-YA laser beam machine, a wavelength of 35
Irradiation was performed with a laser beam of 5 nm and an output of 0.05 mj / pulse. From the observation result of the laser irradiation surface using the SEM, it was confirmed that only the remaining sealing resin could be selectively processed without damaging the solder resist 5 (FIG. 12).

Example 6 An epoxy resin was UV-378 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range: 325 to 410 nm, molecular extinction coefficient: 30800,
m. p. Material 15 in which 1 Wt% is added and dispersed at about 260 ° C.) and an organic nickel quencher SEESORB 612N
H (manufactured by Cipro Kasei: melting point 253-259 ° C) by 10 Wt
%, And dispersed material 16 was prepared. As shown in FIG. 18, a material 16 was applied on a printed wiring board by a screen printing method, leveled, and then heat-cured to form a first layer. A second layer of material 15 was formed in a similar manner.
The thickness of each formed layer was 100 μm. Using a THA-YAG laser processing machine that utilizes the third harmonic of an ND: YAG laser, a wavelength of 355 n is applied to the produced resin layer.
Irradiation was performed with a laser beam of m and an output of 0.05 mj / pulse (FIGS. 19 and 20). From the observation result of the laser irradiation surface using the SEM, it was confirmed that only the sensitizer dispersion layer 15 for ultraviolet light could be selectively processed without damaging the layer 16 in which the quencher was dispersed. (FIG. 20).

Example 7 R-544 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range: 490-580 nm, mp: about 250 ° C.) was added to the epoxy sealing resin at 1 Wt%, and the resin material 14 dispersed therein was dispersed. Got ready.
This is underfilled into the semiconductor element 1 mounted on the epoxy wiring board 6 as shown in FIG. 1, and the sealing resin is cured by performing a heat treatment. Thereafter, as shown in FIG. After the semiconductor element 1 is removed, as shown in FIG. 11, N is applied to the sealing resin remaining on the wiring board.
D: SHA-YA using second harmonic of YAG laser
Using a G laser processing machine, wavelength 532 nm, output 0.0
Irradiation with a laser beam of 5 mj / pulse was performed. From the observation result of the laser irradiation surface using the SEM, the solder resist layer 5
It was confirmed that only the sealing resin residue 20 could be selectively processed without damaging (FIG. 12).

Example 8 As shown in FIG. 6, a sensitizer for infrared laser processing IRG-040
(Nippon Kayaku Co., Ltd .: 800-1200n effective absorption wavelength range)
m, molecular extinction coefficient 104000, m.p. p. About 250 ° C)
13, a material 13 containing 1 Wt% of sensitizer R-544 (manufactured by Nippon Kayaku Co., Ltd .: mp about 250 ° C.)
Wt% added material 14, UV laser processing sensitizer UV
-378 (manufactured by Nippon Kayaku Co., Ltd .: effective absorption wavelength range 325 to 41)
0 nm, molecular extinction coefficient 30800, m.p. p. About 260
C) was added and dispersed at 1 Wt%, and a material 16 having a quencher dispersed therein was prepared. The material 16 was applied on a printed wiring board by a screen printing method, leveled, and then heat-cured to form a first layer. In the same manner, a second layer of the material 15, a third layer of the material 14, and a fourth layer of the material 13 were formed. The thickness of each layer formed was 20 μm. The produced resin layer was processed by an ND: YAG laser processing machine. By scanning with a laser beam having an output of 0.1 mj / pulse, only the fourth layer was processed to form a cavity structure (FIG. 7). Subsequently, the exposed third layer is
Processing was performed by laser light scanning with an output of 0.1 mj / pulse using an HG-YAG laser processing machine (FIG. 8). Similarly,
Using a THA-YAG laser beam machine for the exposed third layer,
Processing was performed by laser light irradiation with an output of 0.05 mj / pulse (FIG. 9). By sequentially irradiating such lasers having different wavelengths, it was possible to form a fine cavity structure of 20 μm in each stage. As a result of observing the laser irradiation surface using the SEM, it was confirmed that the layer 16 in which the quencher was dispersed was not damaged, and the desired processing could be performed on the 13, 14, and 15 layers.

[0048]

According to the present invention, selective processing of resin can be achieved by using a material to which a laser sensitizer or a laser quencher is added, or a material having a part sensitized by a laser or a part quenched by a laser. Can be made possible. By enabling selective machining in this way,
Only the sealing resin on the wiring board can be selectively removed,
Further, it has become possible to easily form a fine structure such as a cavity structure on a wiring board used in an electronic device.

[0049]

[Brief description of the drawings]

FIG. 1 is a view showing Examples 2, 3, 5, and 7, showing a state in which a semiconductor element is mounted on a wiring board using a sealing resin in which a sensitizer is dispersed.

FIG. 2 is a diagram showing a conventional glob top type sealing mode.

FIG. 3 is a view showing a conventional mold type sealing mode.

FIG. 4 is a view showing a conventional underfill type sealing mode.

FIG. 5 is a diagram showing a cross section of a conventional build-up wiring board.

FIG. 6 is a view showing Example 8 and showing an example of a material for forming a multi-stage cavity structure.

FIG. 7 is a view showing Example 8, showing a cavity structure after infrared laser irradiation.

FIG. 8 is a view showing Example 8 and showing a cavity structure after irradiation of a visible laser beam.

FIG. 9 is a view showing Example 8, showing a cavity structure after ultraviolet laser irradiation.

FIG. 10 is a view showing Examples 2, 3, 5, and 7, in which a mounted semiconductor element is removed by a mechanical method such as polishing.

FIG. 11 is a view showing Examples 2, 3, 5, and 7, and is a view in which a sealing resin remaining on a wiring board is removed by laser.

FIG. 12 is a view showing Examples 2, 3, 5, and 7, and is a view showing a state where cleaning is completed.

FIG. 13 is a view showing Example 3 and showing a step of removing a sealing resin residue by using a solvent dipped in a cotton swab.

FIG. 14 is a view showing Examples 2 and 4, and is a view showing a repair method in a state where a semiconductor element is kept attached.

FIG. 15 is a view showing Example 4, in which a resin on the lower surface of the element is processed by infrared light transmitted through the semiconductor element.

FIG. 16 is a view showing Example 4, in which the semiconductor element is removed by solder reflow after the adhesive force of the sealing resin is reduced.

FIG. 17 is a diagram illustrating the fourth embodiment, and is a diagram illustrating a state where cleaning is completely performed by a solvent or a laser.

FIG. 18 is a view showing Example 6 and is a view showing a resin structure for performing selective fine processing by ultraviolet laser.

FIG. 19 is a view showing Example 6 and is a view showing a resin structure before ultraviolet laser irradiation.

FIG. 20 is a view showing Example 6 and showing a resin structure after ultraviolet laser irradiation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor element 2 sealing resin layer in which sensitizer is dispersed 3 solder bump 4 solder ball 5 solder resist layer 6 wiring board layer 7 wire bonding 8 sealing resin 9 lead frame 10 ball bump 11 build-up layer 12 core layer 13 Infrared light sensitizer dispersion layer 14 Visible light sensitizer dispersion layer 15 Ultraviolet light sensitizer dispersion layer 16 Quencher dispersion layer 17 Infrared laser irradiation 18 Visible laser irradiation 19 Ultraviolet laser irradiation 20 Sealing resin residue 21 Hot plate 22 Swab soaked in solvent

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) // B23K 101: 40 (72) Inventor Koji Matsui 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation (72) Inventor Yuzo Shimada 5-7-1 Shiba, Minato-ku, Tokyo NEC Corporation F-term (reference) 4E068 AF01 DA09 DB10 4M109 AA02 EA15 5F061 AA02 BA01 CA21 GA02

Claims (15)

[Claims] 1. A laser processing resin structure comprising a plurality of layers, wherein at least one of the plurality of layers is a layer having a sensitizing effect on laser light. For resin structure. 2. A laser processing resin structure comprising a plurality of layers, wherein at least one of the plurality of layers is a layer in which a compound having a sensitizing effect on laser light is dispersed. Characteristic resin structure for laser processing. 3. A laser processing resin structure comprising a plurality of layers, wherein at least one of the plurality of layers is a layer having a quenching effect on laser light. Resin structure. 4. A resin structure for laser processing comprising a plurality of layers, wherein at least one of the plurality of layers is a layer in which a compound having a quenching effect on laser light is dispersed. Resin structure for laser processing. 5. The semiconductor device according to claim 3, wherein the layer having a quenching effect on the laser light or the layer in which a compound having a quenching effect on the laser light is dispersed is a substrate on which a semiconductor is mounted. Or the resin structure for laser processing according to 4. 6. The method according to claim 1, wherein the plurality of layers are sealing materials for sealing a semiconductor, and a layer having a quenching effect on the laser light or a compound having a quenching effect on the laser light is dispersed therein. The resin structure for laser processing according to claim 3, wherein the layer is a lowermost layer of the sealing material. 7. The laser processing resin structure according to claim 1, wherein the plurality of layers are sealing materials for sealing a semiconductor. 8. The method according to claim 1, wherein at least one of the plurality of layers comprises:
The resin structure for laser processing according to any one of claims 1 to 5, wherein the resin structure is a sealing material for sealing a semiconductor. 9. A method for processing a resin structure, comprising: irradiating a resin structure comprising a plurality of layers with a laser beam to selectively remove at least one of the plurality of layers. 10. The processing of the resin structure according to claim 9, wherein the layer to be selectively removed contains a sensitizer in an effective absorption wavelength range corresponding to the wavelength of the laser beam. Method. 11. At least one of the plurality of layers includes:
The method for processing a resin structure according to claim 9, further comprising a layer in which a quencher is dispersed, wherein the layer in which the quencher is dispersed is not processed by the laser beam. 12. Irradiating a laser beam from a semiconductor element side;
13. The method for processing a resin structure according to claim 9, wherein only the resin material on the lower surface of the semiconductor element is selectively processed by a laser beam passing through the semiconductor element. 13. Irradiating an infrared laser from the semiconductor element side, processing a resin material on a lower surface of the semiconductor element by the infrared laser passing through the semiconductor element, removing the semiconductor element from the wiring board, and removing residual resin. The method for processing a resin structure according to any one of claims 9 to 12, wherein: 14. A method for processing a resin structure, comprising irradiating a resin material comprising a plurality of layers with a laser beam and selectively removing each layer in order from a surface layer to form a cavity structure. 15. Each of the layers to be selectively removed contains a sensitizer having a different effective absorption wavelength range, and each layer is selectively processed with a laser beam having a wavelength corresponding to the effective absorption wavelength range. The method for processing a resin structure according to claim 14, wherein: