KR102243088B1 - Composition for No-Clean Flux - Google Patents

Abstract

The present invention relates to a no-clean flux composition, specifically, to a no-clean flux composition comprising a resin, a solvent and an acid, viscosity, tack, underfill die shear adhesion, Since it exhibits an excellent effect in terms of ball shear adhesion and minimization of residue, it can be usefully used as a no-clean flux composition.

Description

Composition for No-Clean Flux {Composition for No-Clean Flux}

The present invention relates to a non-clean (No-Clean) flux composition, specifically, to a non-clean flux composition comprising a resin (Resin), a solvent and an acid (Acid).

Ball Grid Array (BGA), Flip Chip Ball Grid Array (FCBGA), and Through Silicon Via (TSV) package technologies used in various electronic products and mobile devices are semiconductor processing. As capacity and speed increase, demand is increasing for lighter weight, thinner thickness, and high integration. These BGA, FCBGA and TSV package technologies have the advantage of minimizing signal travel distance and power consumption and maximizing package space through solder bonding rather than wire bonding. Accordingly, the demand for flux materials for solder balls and solder bumping is also increasing.

At this time, flux is a core material that stably removes the oxide film of solder balls or bumps, bonds solder balls to a substrate, or forms solder balls on a wafer, but mostly depends on imports.

Assembly of a typical flip chip system requires (1) flip chip bonding and (2) encapsulation or underfill processes. First, in the flip chip bonding process, a die bumped using a flux is aligned and attached to a bonding pad on a substrate. Thereafter, the module is heated to dissolve the solder to form a metal bond with the bond pad (reflow process). After the flip chip bonding process, the flux residue used in the process is cleaned prior to the encapsulation or underfill process.

However, since the solvent substances required to clean these flux residues are typically very flammable and dangerous substances, some are carcinogenic, they require highly specialized equipment for cleaning and require a high cost for the cleaning step.

In addition, as the ball pitch spacing of semiconductor packages has recently become finer (typically flip chip packages, wafer level packages, etc.), a cleaning process to remove flux residues from the device after the reflow process is completed is not performed. There is still a need for a method of assembling a semiconductor device in a flip chip configuration.

Korean Patent Publication No. 10-2018-0038844

The present inventors have made extensive research efforts to develop a flux composition capable of minimizing residues so that a separate cleaning process is not required after the reflow process during the semiconductor package process. As a result, in the case of a composition containing a synthetic fragrance (Aroma Chemical) resin, a solvent, and an acid, it exhibited excellent effects in terms of viscosity, adhesion, underfill die shear adhesion, ball shear adhesion and residue minimization. -Clean) By finding out that it can be used as a flux composition, the present invention was completed.

Accordingly, it is an object of the present invention to provide a No-Clean flux composition.

The present invention relates to a no-clean flux composition, and more specifically, to a no-clean flux composition comprising a resin (Resin), a solvent and an acid (Acid).

The present inventors have made extensive research efforts to develop a flux composition capable of minimizing residues so that a separate cleaning process is not required after the reflow process during the semiconductor package process. As a result, in the case of a composition containing a synthetic fragrance (Aroma Chemical) resin, a solvent, and an acid, it exhibited excellent effects in terms of viscosity, adhesion, underfill die shear adhesion, ball shear adhesion and residue minimization. -Clean) It was found that it can be used as a flux composition.

Hereinafter, the present invention will be described in more detail.

One aspect of the present invention relates to a No-Clean flux composition comprising a resin, a solvent, and an acid.

In the present specification, the "flux composition" stably removes the oxide film of the solder ball or bump used in the semiconductor package process (Ball Grid Array, Flip Chip Ball Grid Array, TSV package process, etc.), and the substrate It refers to a composition that serves to bond solder balls to or to form solder balls on a wafer.

In the present specification, the "No-Clean flux composition" refers to a flux composition that does not need to be cleaned separately after the reflow process, or that there is little or no need to clean it after the reflow process.

The no-clean flux composition may have sufficient viscosity and tackiness to bond solder balls to a substrate or form solder balls on a wafer. In addition, only a minimum amount of residue can be left during the reflow process, which does not interfere with the subsequent underfill process.

In the present specification, the resin may be a synthetic fragrance (Aromatic Chemical) resin, and "synthetic fragrance" means a substance that gives off a scent expressed by a single chemical structure, and "synthetic fragrance resin" means a scent expressed by a single chemical structure. It means resin. Synthetic fragrances may include isolated fragrances separated from natural fragrances (free fragrances) and pure synthetic fragrances produced by synthetic reactions.

The resin may be selected from the group consisting of compounds represented by the following Formulas 1 to 5, for example, but is not limited thereto.

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

Since the resin has a high vapor pressure and high volatilization, it is possible to impart sufficient viscosity and tackiness to the no-clean flux composition during the soldering process, and reflow due to the low boiling point and high volatility properties. After the (Reflow) process, the residue of the no-clean flux composition can be minimized. In addition, it is possible to minimize contamination of reflow equipment while volatilization.

The resin may be included in an amount of 60 to 95 parts by weight, 65 to 95 parts by weight, 70 to 95 parts by weight, 75 to 95 parts by weight, 80 to 95 parts by weight, or 85 to 95 parts by weight, based on the total weight of the non-clean flux composition. However, it is not limited thereto. If the invention is carried out outside the above-described weight, for example, if it is carried out in excess of the above weight, insufficient soldering may occur, and if it is carried out under the above weight, the amount of residue may increase and uncured underfill may occur. Failure to protect the solder balls can lead to poor reliability (solder ball cracks or short circuits).

In the present specification, the solvent may include any solvent used to prepare the flux in the art, for example, isopropyl alcohol, ethanol, acetone, toluene, xylene, ethyl acetate, ethyl cellosolve, butyl cello Solve, glycol ether, hexyldiglycol, (2-ethylhexyl)diglycol, phenylglycol, butylcarbitol, octanediol, α-terpineol, β-terpineol, tetraethylene glycol dimethyl ether, Trimellitic acid tris (2-ethylhexyl), sebacic acid bis (2-ethylhexyl), diethylene glycol monobutyl ether, or a combination thereof, but is not limited thereto.

The solvent is based on the total weight of the non-clean flux composition, 5 to 40 parts by weight, 5 to 35 parts by weight, 5 to 30 parts by weight, 5 to 25 parts by weight, 5 to 20 parts by weight, 5 to 15 parts by weight or 5 It may be included in an amount of 10 parts by weight, but is not limited thereto. In the case of carrying out the invention outside the above-described weight, for example, if the composition exceeds the weight, the viscosity of the composition decreases, resulting in insufficient soldering, and if the weight is less than the above weight, the viscosity of the composition increases. Bridges can occur.

In the present specification, the acid may be selected from the group consisting of compounds represented by the following Formulas 6 to 8, for example, but is not limited thereto.

[Formula 6]

[Formula 7]

[Formula 8]

Even if the acid remains as a residue after the reflow process, it is used as an epoxy curing agent to cure the underfill, so there is no problem in reliability, whereas the acid (Glutaric acid, Succinic acid, Adipic acid) mainly used in conventionally no-clean flux compositions. acid, Diglycolic acid, Polyglicolic acid, Glycolic acid, etc.) have no or little reactivity with epoxy if they remain as residues, so there is a problem that may cause reliability problems in subsequent processes such as underfill.

More specifically, when the underfill is not cured, the solder ball and the underfill cannot be bonded to protect the solder ball, so it may cause a solder ball crack or a solder ball short circuit due to thermal shock or CTE mismatch. In addition, since the acid can harden the underfill even if it remains as a residue after the reflow process, there is no problem in reliability.

The acid is based on the total weight of the non-clean flux composition, 1 to 10 parts by weight, 2 to 10 parts by weight, 3 to 10 parts by weight, 4 to 10 parts by weight, 5 to 10 parts by weight, 6 to 10 parts by weight, 7 to 10 parts by weight, 8 to 10 parts by weight, 9 to 10 parts by weight, 1 to 9 parts by weight, 1 to 8 parts by weight, 1 to 7 parts by weight, 1 to 6 parts by weight, 2 to 9 parts by weight, 2 to 8 parts by weight Parts, 2 to 7 parts by weight, 2 to 6 parts by weight, 3 to 9 parts by weight, 3 to 8 parts by weight, 3 to 7 parts by weight, 3 to 6 parts by weight, 4 to 9 parts by weight, 4 to 8 parts by weight, It may be included in 4 to 7 parts by weight, 4 to 6 parts by weight, 5 to 9 parts by weight, 5 to 8 parts by weight, 5 to 7 parts by weight, or 5 to 6 parts by weight, but is not limited thereto. When the invention is carried out outside the above-described weight, for example, when the invention is carried out in excess of the above weight, a problem of increasing residues may occur, and when the invention is carried out under the above weight, soldering defects may occur.

The present invention relates to a no-clean flux composition, specifically, to a no-clean flux composition comprising a resin, a solvent and an acid, viscosity, tack, underfill die shear adhesion, Since it exhibits an excellent effect in terms of ball shear adhesion and minimization of residue, it can be usefully used as a no-clean flux composition.

1 is a result of confirming whether a solder ball is formed according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for describing the present invention in more detail, and it will be apparent to those of ordinary skill in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention. .

Example. No-clean flux composition

Di-ethylene glycol monobutyle ether, isobornyl cyclohexanol (IBCH) and acid (2PZ-CNS or C11-CNS) were added to a 500 ml beaker, and the mixture was heated to 150°C. After melting, the mixture was stirred at 150 rpm for 30 minutes and then cooled to 30° C. or less while maintaining the stirring speed to prepare a flux composition. The specific composition is shown in Table 1 below.

Ingredients (parts by weight) Isobornyl cyclohexanol Di-ethyleneglycol monobutyle ether Acid Sum 2PZ-CNS C11-CNS Example 1 90 6 One - 97 Example 2 90 6 3 - 99 Example 3 90 6 5 - 101 Example 4 90 6 7 - 103 Example 5 90 6 9 - 105 Example 6 90 6 - One 97 Example 7 90 6 - 3 99 Example 8 90 6 - 5 101 Example 9 90 6 - 7 103 Example 10 90 6 - 9 105

Comparative Example 1. Existing flux composition

By varying some components of the composition, a flux composition was prepared in the same manner as in Examples. The specific composition is shown in Table 2 below.

Ingredients (parts by weight) Isobornyl cyclohexanol Di-ethyleneglycol monobutyle ether Acid Sum Glutaric acid Adipic acid Comparative Example 1 90 6 4 - 100 Comparative Example 2 90 6 - 4 100

Experimental Example 1. Viscosity measurement

For the compositions of Examples and Comparative Examples, 0.5 ml of each composition was quantified in a viscometer (Brookfield DV-II), and the viscosity value was measured at a speed of 5 rpm using a spindle (Spindle No. 51), and repeated three times. The average value was shown after measurement. The results are shown in Table 3 below.

Viscosity (mPa) Example 1 3225 Example 2 6852 Example 3 9449 Example 4 13628 Example 5 15161 Example 6 4085 Example 7 7424 Example 8 10304 Example 9 13024 Example 10 16632 Comparative Example 1 5021 Comparative Example 2 5201

As can be seen from Table 3 above, it can be seen that the composition of the present invention is at least similar or superior in viscosity compared to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples.

Experimental Example 2. Tackiness measurement

For the compositions of the Examples and Comparative Examples, using a universal testing machine UTM (universal testing machine) under JIS-Z-3284 conditions (Load: 50 g, Down Speed: 2 mm/s, Up Speed: 10 mm/s) After setting, each composition was printed to a thickness of 0.2 mm, and then measured by pressing a probe having a diameter of 5.1 mm for 0.2 seconds. The results are shown in Table 4 below.

Adhesiveness(gf) Example 1 142 Example 2 156 Example 3 162 Example 4 170 Example 5 172 Example 6 144 Example 7 151 Example 8 163 Example 9 168 Example 10 176 Comparative Example 1 147 Comparative Example 2 148

As can be seen from Table 4 above, it can be seen that the composition of the present invention is at least similar or better in terms of adhesion compared to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples.

Experimental Example 3. Underfill Die Shear Strength (DST) Measurement

For the compositions of Examples and Comparative Examples, in order to check whether the residue affects the underfill hardening, a 350 x 350 x 0.3 mm Copper Clad Laminated Board printed circuit board (PCB) was used. After each composition was applied to a thickness of 50 um, reflow was performed three times in a reflow oven under _{O 2 conditions of 200 ppm or less.} ^{After reflow, a silicon chip (2x2 mm 2} ) was attached on the copper foil using the underfill adhesive (UF3300, epoxy, silica filler 60% by weight) manufactured by our company without washing the remaining residue on the PCB copper foil. After curing for 1 hour, shear strength was measured using a Dage 4000. The results are shown in Table 5 below.

Underfill DST(kgf) Example 1 5.32 Example 2 6.97 Example 3 8.47 Example 4 7.32 Example 5 4.25 Example 6 4.98 Example 7 6.44 Example 8 9.61 Example 9 8.22 Example 10 5.41 Comparative Example 1 1.24 Comparative Example 2 1.12

As can be seen from Table 5, it can be seen that the composition of the present invention is at least similar or superior to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples in terms of underfill die shear adhesion.

Experimental Example 4. Confirmation of formation of solder balls and measurement of ball shear strength (BST)

For the compositions of Examples and Comparative Examples, after attaching solder balls (SAC305, Deoksan Hi-Metal, Korea) using each composition on a PCB coated with OSP (Organic Solderability Preservative), reflow (maximum temperature: 240 °C) It was confirmed whether the solder ball was formed well (see FIG. 1). Then, the ball shear adhesion (BST) of the solder ball formed using Dage 4000 was measured (solder ball size: 300 μm, measurement speed: 500 μm/s, shear height: 20 μm). The results are shown in Table 6 below.

BST(gf) Example 1 341 Example 2 368 Example 3 394 Example 4 371 Example 5 362 Example 6 338 Example 7 354 Example 8 385 Example 9 364 Example 10 355 Comparative Example 1 382 Comparative Example 2 372

As can be seen in Fig. 1 and Table 6, it can be seen that the composition of the present invention is at least similar or better in terms of ball shear adhesion compared to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples.

Experimental Example 5. Acid value measurement

For the compositions of Examples and Comparative Examples, in order to check the acidity that affects the soldering effect, 10 g of each composition was dissolved in 100 ml of a mixture of ethanol: methanol (2: 1), and phenolphthalein was 4 to 5 Droplets were added and stirred, and then 0.1 N KOH solution was titrated using a burette, and the acid value was measured using the following calculation formula. The results are shown in Table 7 below.

(S: collection amount for the sample, a: initial 0.1 N KOH amount (ml), b: remaining 0.1 N KOH amount (ml), f: 0.1 N KOH titer (usually 1 used))

Acid value Example 1 8.92 Example 2 20.7 Example 3 35.8 Example 4 52.82 Example 5 65.34 Example 6 9.82 Example 7 21.66 Example 8 38.32 Example 9 54.63 Example 10 66.41 Comparative Example 1 25.6 Comparative Example 2 23.3

As can be seen from Table 7, the compositions of the present invention (Examples 3-5 and 8-10) were found to be superior to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples in terms of acid value.

Experimental Example 6. Measurement of residue after reflow

For the compositions of Examples and Comparative Examples, after printing each composition to a thickness of 50 μm on a slide glass, the weight of the sample was measured, and reflow (maximum temperature: 240° C.) was 3 in a reflow oven (1707MK III, Heller). After repetition, the final remaining weight of each composition was re-measured. The results are shown in Table 8 below.

Residue after reflow (wt%) Example 1 9.6 Example 2 9.2 Example 3 8.5 Example 4 7.6 Example 5 6.4 Example 6 10.4 Example 7 9.4 Example 8 8.8 Example 9 7.4 Example 10 6.3 Comparative Example 1 10.2 Comparative Example 2 10.4

As can be seen from Table 8, it can be seen that the composition of the present invention is superior to the conventional materials (Comparative Examples 1 and 2) shown in Comparative Examples in terms of residue after reflow.

The non-clean flux composition of the present invention (Examples 1 to 10) is generally superior in terms of viscosity, tackiness, underfill DST, and residue after reflow compared to the composition using the conventional acid shown in Comparative Example (Comparative Examples 1 and 2). Appeared.

In particular, in the case of a composition containing 5 to 10 parts by weight of an acid (Examples 3-5 and 8-10), in all aspects of the experimental example, a composition using a conventional acid shown as a comparative example (Comparative Examples 1 and 2) It can be seen that it has properties that are very suitable for application to a no-clean flux composition, appearing to be superior.

Claims (8)

A No-Clean flux composition containing an Aromatic chemical resin, a solvent and an acid, wherein the synthetic perfume resin is selected from the group consisting of compounds represented by the following Chemical Formulas 1 to 5, The acid is selected from the group consisting of compounds represented by the following formulas 6 to 8, a no-clean flux composition:
[Formula 1]

,
[Formula 2]

,
[Formula 3]

,
[Formula 4]

,
[Formula 5]

,
[Formula 6]

,
[Formula 7]

, And
[Formula 8]

.
delete delete The method of claim 1, wherein the solvent is isopropyl alcohol, ethanol, acetone, toluene, xylene, ethyl acetate, ethyl cellosolve, butyl cellosolve, glycol ether, hexyldiglycol, (2-ethylhexyl)diglycol, Phenyl glycol, butylcarbitol, octanediol, α-terpineol, β-terpineol, tetraethylene glycol dimethyl ether, trimellitic acid tris (2-ethylhexyl), sebacic acid bis (2-ethyl) Hexyl), diethylene glycol monobutyl ether, and combinations thereof. delete The non-clean flux composition of claim 1, wherein the acid is contained in an amount of 1 to 10 parts by weight based on 90 parts by weight of the synthetic perfume resin. delete delete

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