JPS59227970A - Abrasive - Google Patents

Abstract

PURPOSE:To provide an abrasive which effectively removes fins formed in the production of a molding such as semiconductor without causing damage to the molding, prepd. by adding a rigid abrasive in powder to a synthetic resin in granules. CONSTITUTION:A rigid abrasive in powder (e.g. glass powder having an average praticle diameter of about 0.1mm. is mixed in an amt. of about 1-100vol% into a synthetic resin soln. (e.g. unsatd. polyester resin soln.) and a hardener is added thereto. The cured resin is crushed and classified to obtain a polygonal abrasive 7 with such a structure that rigid abrasive in powder 6 is attached to the surface and incorporated in the interior of a synthetic resin compsn. in particle 5 having an average diameter of about 0.5-1mm.. When the abrasive 7 impinges upon a workpiece, cracking occurs readily from the rigid abrasive powder 6 as starting point and growth of cracks eventually lead to partial coming-off of the resin compsn. and formation of new sharp edges, thus preventing lowering of a fin- removing ability of the abrasive over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an abrasive material, and particularly to an abrasive material suitable for removing pars from synthetic resins.

[Technical background of the invention and its problems]

For example, in the manufacturing process of semiconductor devices such as ICs and LSIs, a lead frame on which a semiconductor element is mounted is housed in a mold for molding, and then epoxy resin is injected into the mold as shown in Figure 1. A semiconductor molded product (3) is formed in which a single semiconductor (not shown) on a lead frame (1) is sealed with a resin layer (2). However, during such mold forming, resin particles (4) are generated on the lead frame (1) near the resin layer (2) and between the leads of the lead frame (1), so it is necessary to perform post-processing after molding. Removal step of resin particles (4) is required. For this reason, in the past, hard ωF materials such as alumina, silicon carbide, and glass beads, or soft abrasive materials such as walnut shells were applied to the resin pad (4) of the lead frame (1) at high speed. Inject this resin Paris (4)
...is destroyed and removed. However, when a hard abrasive material is used, its hardness is 1 (C70 or higher), whereas the hardness of epoxy resin is around H C70, and the abrasive material is much harder than epoxy resin. Because the specific gravity is more than 4 times thicker, resin 71 month 4)...
When removing the molded product (3), the surface of the molded product (3) was damaged and its appearance was damaged, and moisture penetrated from uneven parts of the molded product (3), which adversely affected the reliability of the conductor. There was a problem. On the other hand, when a soft abrasive material is used, the abrasive force is weak, so it is necessary to spray at a high pressure even when a hard abrasive material is used. As a result, there was a drawback that not only the lead frame (1) might be bent, but also the running cost would increase. If soft abrasive Ws material is still used, this abrasive material and molded product (3
) Static electricity is generated, and this static electricity causes the crushed powder of the abrasive to firmly stick to the surface of the molded product (3), reducing the wettability of the solder and causing damage in the subsequent process. This may cause poor appearance in semi-[1] coat or plating, and cause corrosion of the lead frame (1).

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide an abrasive material that can efficiently remove resin debris during the molding of molded products such as semiconductors, and does not cause damage to the molded products. That is.

[Summary of the invention]

The abrasive material of the present invention is made by holding a powdery hard abrasive material such as glass beads in synthetic resin granules.

The synthetic resin particles include thermosetting resins such as urea resin, melamine resin, polyester resin, alkyd resin, and epoxy resin, or polyamide, polycarbonate,
Thermoplastic resins such as polystyrene can be used. In particular, when a thermosetting resin is used, it is suitable for removing resin particles because sharp edges are constantly created by the impact during the injection process. The particle size of these synthetic resin particles is
The abrasive can be freely selected depending on its purpose, but for example, when used for removing resin particles from molded products, the average particle diameter (l/2 of the sum of the maximum diameter and minimum diameter of one particle) is 0. 5-1
．． It is desirable to have a peak within the range of Q myn. The shape of the synthetic resin particles may be arbitrary, such as spherical or polygonal.

On the other hand, a powdery hard abrasive material has a greater polishing ability than a synthetic resin granule, and can improve the polishing ability even more than the synthetic resin granule alone.

As such a hard abrasive material, the average particle size is Q, 1 mm.
Glass beads of front and back (particles 2Jlt150) are suitable.

The mixing ratio of such a powdery hard abrasive material to the synthetic resin granules is 1 to 100% by volume, and the optimum range is 5 to 30% by volume.

The abrasive material in the present invention is made by holding a hard abrasive material in the form of a powder in synthetic resin granules, and specifically there are two types of abrasive materials shown below.

■An abrasive material in which powdered hard XIυ+ abrasive material is dispersed and mixed not only on the surface of synthetic resin granules but also inside them.

■Powdered hard abrasive material is attached only to the surface of synthetic resin granules @Abrasive material.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

First, add an average particle size Q of 1 mm to the unsaturated polyester resin liquid.
The following glass peas were added and stirred to mix uniformly, and then a curing agent was added to produce an unsaturated polyester cured product. Subsequently, this cured product was coarsely pulverized using a crusher, a hammer, etc., and then the coarse particles were pulverized using a ball mill, a roll mill, an impact pulverizer, or the like. After that, the particles were classified through a sieve and glass beads (6 )...is 25 performance%
Adhesive, mixed polygonal abrasives (gained strength).

Next, the removal of resin pars from a semiconductor molded product using the abrasive material will be explained using the wet-type plast apparatus shown in FIG. First, the hopper (9) installed in the pressurization chamber (8)
) inside the abrasive (7)... and water (+0) and '! i=1:
Accommodate at a ratio of 9. Next, the first pump (11)
The QfN material (force...) is sucked in together with water (IcI), and this is forcibly fed to the bottom of the hopper (9), stirring it and uniformly dispersing the abrasive material (7)... Then, the second pump (1) was activated to suck up the slurry and introduce it into the gun (13), which was then dispersed and accelerated by compressed air from the air introduction pipe tta to convert it into water. .

The processing chamber (
8) Semiconductor molded product transported inside (not shown)
Spray it towards. When the jet stream is injected onto the molded product in this way, as shown in Fig. Adhered resin particles (4)
collide with Resin Paris (4) is made of thermosetting epoxy resin and is brittle and easily broken, so glass beads (6
) The polishing force of the polished F<'ji material (
Due to the three forces of force and the vibrations accompanying this force,
Cracks ([6) occur in the resin pad (4). Water entered the crack 0()) of the resin pad (4), and the water entered the lead frame (1) and the +'y'41
1 Thf is inserted into the interface of the resin 71 (4) and acts to float it relative to the lead frame (11), so the resin bar IJ (a) is easily peeled off.Furthermore, the abrasive (
Because the sword collides with the crack 06) of the greasy burr (4) many times, the resin burr (4) is completely removed due to the lifting effect of the resin burr (4) caused by the infiltrated water. will be removed. In particular, the abrasive material (7) of this example has stronger abrasive power than the case of synthetic resin alone, so it can also remove the resin particles with a thickness of 1 to 10 μm to about 50 μm that are sandwiched between the leads of the lead frame. Can be removed. Moreover, when the abrasive material (force) of this example collides with the workpiece, cracks are likely to occur starting from the glass beads (6)...
Eventually, the crack will grow and some will fall off, easily creating new sharp edges. In other words, since the abrasive material of this embodiment has the action of generating sharp edges (self-sharpening action), the ability to remove resin particles can be maintained for a long period of time.

Incidentally, using the abrasive material (force) of this example containing glass beads (6) and the abrasive material made of the same resin that does not contain glass beads (6), the injection pressure and injection flow rate were Deburring was performed on 100 test pieces with resin particles attached under the same conditions for the injection time, and it was determined how many pieces were completely removed.As a result, it was found that the abrasive material that does not contain glass beads Resin particles remained in 20 to 30 of the test pieces, but in the case of the abrasive material (7) of this example, resin particles were completely removed from all 1.00 test pieces. In other words, when comparing the processing time required to completely remove the resin particles from all 100 test pieces using the conventional abrasive material and the abrasive material of this example, the abrasive material of this example (7) The processing time can be reduced by about 20%. Therefore, the resin paris (4) can be completely removed without increasing the ejection pressure of the three-phase high-speed injection flow 09, and the lead frame by single-shell injection RTU51 can be The abrasive material of this example is able to prevent bending.Since the main body is made of synthetic resin, the abrasive material of this example is stronger than the case of a single hard abrasive material such as alumina or silicon carbide. ) and the jig used for deburring, making it difficult to embed or embed, and the deburrs and polished side can be easily removed by cleaning in the post-process.As a result, solder coating and plating can be performed without impairing solder wettability. It can prevent later appearance defects and corrosion during use.Furthermore, since the glass beads (6) and the synthetic fat particles (5) are integrally bonded, they can be used for a long period of time. Even if the total amount of research material is insufficient for use, there is no need to mix and replenish the glass beads and synthetic resin granules in a fixed ratio, and there is an advantage that the material can be supplied as is.

Incidentally, the uninvented abrasive material is not limited to the one in the above embodiment, but as shown in FIG. An abrasive material (7') may also be used. This VI abrasive material (for example, the synthetic resin granules (5) with an average particle size of around 0.3 mm are dipped in an adhesive solution, or the same granules (5) are sprayed with an adhesive solution. The abrasive material (7) shown in FIG. As the adhesive 08), silicone resin or epoxy resin is suitable. When the glass beads t1η... are bonded using the latter epoxy resin, the glass beads (17)... are firmly fixed to the synthetic resin granules (5), so they are not easily bonded to each other during the polishing process. When the glass beads fi71... separate from the synthetic resin granules (5), a crack occurs, and a new cutting edge is generated starting from the generated crank. Force can be maintained at a constant level for a long period of time.

Also, like the above-mentioned commercial example, it has the advantage of being easy to replenish. On the other hand, when silicone resin is used as the adhesive (18), the adhesive strength is lower than that of epoxy resin.

Furthermore, as another example, polyoxyethylene alkyl ethers are added to the synthetic resin particles in an amount of o, o o i to 1% by weight, together with glass peas.

Surfactants such as polyoxyethylene alkyl esters may also be retained with the glass beads.

The holding form may be attached only to the surface of the synthetic resin body in the form of a film, or may be mixed in the form of fine particles inside and on the surface of the synthetic resin body. By doing this, together with the effect of glass beads being mixed in the synthetic resin body, the surface tension of the slurry is lowered and its permeability into cracks that occur in the resin layer is improved. In addition to promoting the deburring effect, it is possible to prevent charging of the molded product and facilitate the cleaning process for deburring and polishing debris. In addition, as shown in Fig. 6, an abrasive material (7) with glass beads (2G... The abrasive material according to the present invention can be applied to semiconductor molds and other four molded products as described in detail above. Resin particles generated during molding can be easily and quickly removed without causing damage to the molded product, and the molded product can be easily cleaned after removing the resin particles. .

[Brief explanation of the drawing]

Fig. 1 is a plan view showing a semiconductor molded product, Fig. 2 is a sectional view of an abrasive material showing an embodiment of the present invention, and Fig. 3 is a plan view showing a semiconductor molded product.
An explanatory diagram showing a type of wet blasting equipment used for blasting with the abrasive material shown in the figure, (1)...Lead frame (2)...Resin layer, (3)...
・Semiconductor molded product, (4)... Resin Paris, (5
)...Synthetic resin granules, (6), (lη, glass beads, (9) '...hopper,
QO)...Water, (Ll), (12) =-pump,
(131...if 7, (15)...Three-phase high-speed jet flow, (t6)...Crack. Agent Patent attorney Nori Chika Fumoto Yu (and 1 other person) Zu 1 Figure T20 Lower 50

Claims (5)

[Claims] (1) An abrasive material comprising a synthetic side bending granular material and a powdery hard abrasive material held in the synthetic wood 11￥f granular material. (2) The abrasive material according to item 1 of the scope of patent d11, characterized in that the powdery hard abrasive material is attached to the surface of a synthetic grain granule. (3) The powdery hard abrasive material is dispersed and mixed not only on the surface of the combined fat granules but also in the interior thereof. Material. (4) The abrasive material according to claims 1 to 3, wherein the synthetic grain particles are made of a thermosetting resin. (5) The abrasive material according to claims 1 to 3, wherein the powdery hard material is a glass piece.