HK1174304B - Method for applying liquid material - Google Patents

Description

Method for applying liquid material

Technical Field

The present invention relates to a method and a program for filling a gap between a substrate and a work placed thereon with a liquid material discharged from a discharge device by utilizing a capillary phenomenon, and more particularly to a method and a program for correcting a variation in a discharge amount and stabilizing a coating shape without changing a moving speed of the discharge device in an underfill filling process of a semiconductor package.

Background

One of the mounting techniques of a semiconductor chip is a technique called a "flip chip method". In the flip chip method, a bump-like electrode is formed on the surface of a semiconductor chip and is directly connected to an electrode pad on a substrate.

In flip chip packaging, in order to prevent stress generated by a difference in thermal expansion coefficient between the semiconductor chip 1 and the substrate 2 from concentrating on the connection portion 3 and causing the connection portion 3 to be broken, a gap between the semiconductor chip 1 and the substrate 2 is filled with a resin 4 to reinforce the connection portion 3. This step is referred to as "underfill" (see fig. 1).

The underfill process is performed by applying a liquid resin along the outer periphery of the semiconductor chip, filling the resin in the gap between the semiconductor chip and the substrate by capillary action, and then curing the resin by heating in an oven or the like.

In the underfill process, a change in viscosity of the derived resin material with the passage of time is considered. The reason is that when the viscosity is increased, the discharge amount from the material discharge port is reduced, and the capillary phenomenon becomes insufficient, which causes a problem that an appropriate amount of the material cannot be filled in the gap. When the viscosity changes drastically, the discharge amount may decrease by 10% or more after 6 hours, for example. Therefore, it is necessary to correct a change in the discharge amount due to a change in viscosity with time.

However, a dispenser is generally used for filling the resin material used in the underfill process. One of the dispensers is a jet dispenser that ejects droplets of a liquid material from a nozzle and discharges the droplets.

A method of performing the underfill dispensing process using a jet dispenser is disclosed in Japanese patent laid-open No. 2004-344883 (patent document 1). That is, patent document 1 discloses a method for discharging a viscous material onto a substrate using a jet dispenser, including: preparing the total volume of the viscous material to be discharged and the length of the viscous material for discharging the total volume; acting to coat a plurality of droplets of viscous material on a weight scale; generating a feedback signal indicative of a weight of the plurality of viscous material droplets coated on the weight scale; and determining a maximum relative speed between the dispenser and the substrate so that the total volume of the viscous material is discharged in the longitudinal direction.

The method of patent document 1 further includes: determining respective volumes of a plurality of droplets of liquid material; obtaining the total number of droplets necessary for making the total volumes substantially equal; obtaining a distance between droplets necessary for substantially uniformly distributing the droplets of the viscous material in the longitudinal direction; and determining a rate value at which the droplets of the viscous material are discharged from the dispenser so that the viscous material can be discharged in a total volume in the longitudinal direction at the maximum relative speed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2004-344883

Disclosure of Invention

(problems to be solved by the invention)

Patent document 1 belongs to a technique for uniformly discharging in the longitudinal direction, but there is still room for improvement from the following viewpoints.

That is, the ejection type dispenser discharges one drop of liquid material in one cycle of an open state in which an internal piston is raised to open a valve seat and a closed state in which the piston is lowered to close the valve seat. When the dispenser is used to perform the linear coating, the above cycle is repeated at a constant interval while the dispenser is moved at a constant speed.

However, when the linear coating having the corner portions such as L-shape and U-shape is performed along the outer periphery of the chip, the speed must be reduced at the corner portions so that the moving direction can be changed. Therefore, when the ejection is performed at a constant cycle, the liquid material stays at the corner, and the fillet (フィレット) of the liquid material oozing portion from the chip cannot be formed at a constant width. In addition, in the underfill process, even in the case of linear application without a corner portion, the fillet may be increased or decreased in the middle of the line due to the difference in the penetration rate of the liquid material into the gap, and thus a constant width cannot be formed.

Accordingly, an object of the present invention is to provide a method, an apparatus, and a program for filling a liquid material, which can correct a change in a discharge amount without changing a moving speed of a discharge device and can stabilize an application shape.

(means for solving the problems)

In order to solve the above-mentioned problems, it is considered that the speed is changed in the corner portion or the portion where the permeation rate is different, but the acceleration derived from the speed change is abruptly changed, which causes an increase in mechanical load and vibration, and thus is difficult to adopt.

The inventors first invented a novel method of correcting the discharge amount by adjusting the pulse number in the conventional method of performing the underfill process as in patent document 1. In the coating method, a liquid material is discharged from a nozzle while a nozzle and a workpiece are relatively moved to form a desired coating pattern, and a predetermined coating amount of the liquid material is applied to the workpiece, the coating method including: an initial parameter setting step of specifying the number of times for transmitting the discharge pulse signal and the pause pulse signal as a total pulse number, specifying the number of discharge pulse signals necessary for achieving the coating amount among the total pulse number, and specifying the remaining number as a pause pulse signal; a correction amount calculation step of measuring a discharge amount from the nozzle at a timing of a correction period in a preset correction period and calculating a correction amount of the discharge amount; and a discharge amount correction step of adjusting the number of discharge pulse signals and the number of pause pulse signals based on the correction amount calculated in the correction amount calculation step. Preferably, in the discharge amount correction step, the discharge amount is corrected without changing the frequency (for example, several tens to several hundreds of hertz) at which the discharge pulse signal and the pause pulse signal are transmitted.

In this method, when the application pattern is formed by periodically transmitting a pulse signal in which the number of discharge pulses and the number of pause pulses are in a predetermined ratio, if the ratio of the numbers of pulses is changed by performing correction, the length of the application pattern and the application speed (which may be replaced with the application time) are not changed, and therefore the period formed by the combination of the discharge pulses and the pause pulses ends, that is, the period does not coincide with the end of the application pattern. For example, when the discharge pulse is to be transmitted at the end of the application pattern, if the period is set to the pause pulse state at the end of the cycle, the discharge amount varies slightly.

The present invention further provides a technique for correcting the discharge amount by designing a plurality of discharge cycles and adjusting the position at which the discharge cycles are switched.

A method for filling a liquid material according to a first aspect of the present invention is a method for filling a liquid material discharged from a discharge device into a gap between a substrate and a workpiece placed thereon by utilizing a capillary phenomenon, the method including: a step of forming a coating pattern composed of a plurality of continuous coating regions; a discharge cycle allocation step of allocating a plurality of discharge cycles in which the number of discharge pulses and the number of pause pulses are combined at a predetermined ratio to each application region; and a correction amount calculation step of measuring a discharge amount from the discharge device at a time of the correction period in a preset correction period and calculating a correction amount of the discharge amount; the method further includes a discharge amount correction step including: adjusting the number of the discharge pulses and the number of pause pulses included in the coating pattern based on the correction amount calculated in the correction amount calculating step; and/or adjusting the length of at least the first coating region and the other one or two coating regions continuous with the first coating region without changing the discharge amount per unit time in each coating region.

In the method for filling a liquid material according to the second aspect of the present invention, in the discharge cycle distribution step according to the first aspect of the present invention, the discharge cycle includes a discharge cycle to which the multi-application regions are distributed.

In the method for filling a liquid material according to the third aspect of the present invention, in the correction amount calculating step, the correction amount of the discharge amount is calculated based on a difference between a measured value of the weight of the liquid material discharged for a certain period of time and a theoretical value of the liquid material for the certain period of time.

A method for filling a liquid material according to a fourth aspect of the present invention is the first or second aspect of the present invention, wherein in the correction amount calculating step, the correction amount of the discharge amount is calculated based on: a measured value of the weight of the liquid material discharged for a certain period of time; a theoretical value for the certain time; the length of each coated area; and a ratio of a discharge amount of any one of the application regions to a reference amount of the other one or two continuous application regions, when the discharge amount of the one of the application regions is set as the reference amount.

A fifth aspect of the present invention is the liquid material filling method according to any one of the first to fourth aspects of the present invention, wherein in the discharge amount correction step, the correction of the discharge amount is performed without changing the frequency of sending the discharge pulse and the pause pulse.

A method of filling a liquid material according to a sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects of the present invention, an allowable range for determining whether or not to perform correction is set in a step before the correction amount calculation step, and correction is performed when the allowable range is exceeded.

A seventh aspect of the present invention is the method for filling a liquid material according to any one of the first to sixth aspects of the present invention, wherein the correction cycle is set based on time information, the number of pieces of work, or the number of pieces of substrates, which is input by a user as the correction cycle.

A method of filling a liquid material according to an eighth aspect of the present invention is characterized in that, in any of the first to seventh aspects of the present invention, in the discharge amount correction step, the correction of the discharge amount is performed without changing the relative movement speed of the discharge device and the workpiece and the overall length of the application pattern.

The apparatus of the ninth aspect of the present invention is characterized by being a coating apparatus having: a liquid material supply unit for supplying a liquid material; a discharge device having a discharge port for discharging the liquid material; a metering section for metering the amount of the liquid material discharged from the discharge port; a driving part for making the discharge port and the workpiece move relatively; and a control unit for controlling these operations; in the apparatus, the control section may perform the filling method according to any one of the first to eighth aspects of the present invention.

A tenth aspect of the present invention is a program for causing a control section in a coating apparatus to perform the filling method described in any one of the first to eighth aspects of the present invention, wherein the coating apparatus comprises: a liquid material supply unit for supplying a liquid material; a discharge device having a discharge port for discharging the liquid material; a metering section for metering the amount of the liquid material discharged from the discharge port; a driving part for making the discharge port and the workpiece move relatively; and a control unit for controlling these operations.

(Effect of the invention)

According to the present invention, since the application pattern can be formed without limitation to uniform discharge along the workpiece (chip), it is possible to flexibly cope with a difference in the shape of the workpiece and the penetration rate of the liquid material, and to form a fillet having a constant width.

Further, since the coating amount can be corrected without changing the moving speed, occurrence of mechanical load, vibration, and the like can be suppressed.

Further, since one application pattern includes a plurality of discharge cycles, it is possible to form one application pattern by combining discharge cycles that realize different discharge amounts, and thus it is possible to finely set a desired application amount.

Compared with the case of performing correction on each droplet, the discharge amount correction process of the present invention has a simpler sequence and is less prone to errors caused by calculation. Further, since the amount of coating can be corrected without changing the relative movement speed of the nozzle and the workpiece, the coating length, and the frequency of the pulse signal, it is easy to control the amount of coating necessary for the purpose of realizing correction with higher accuracy than in the conventional art.

Further, in the correction performed by adjusting the switching position in the discharge cycle, since the correction of the application amount is performed without changing the discharge amount per unit time, the supply amount (discharge amount) of the liquid material from the discharge device does not change with respect to the amount of penetration of the liquid material into the gap before and after the correction, and thus a fillet of a certain width can be always formed.

Drawings

Fig. 1 is a side sectional view for explaining an underfill process.

Fig. 2 is an explanatory view showing a coating layout case.

Fig. 3 is an explanatory diagram of correction amount calculation.

Fig. 4 is a schematic perspective view of the coating apparatus of example 1.

Fig. 5 is a main part sectional view of the discharge device of embodiment 1.

Fig. 6 is an explanatory diagram for explaining a pulse signal transmitted to the ejection device of example 1.

Fig. 7 is a flowchart illustrating a correction procedure by the pulse number adjustment.

Fig. 8 is a flowchart illustrating a correction procedure performed to switch the position adjustment in the ejection cycle.

Fig. 9 is an explanatory view showing a coating layout case of example 3.

Description of the symbols

1 chip, work

2 base plate

3 connecting part

4 resin, liquid Material

5 first coating region

6 second coating region

7 coating direction

8 coating device

9 XY driving mechanism

10 weight meter

11 conveying mechanism

12 control part

13 discharge device

14 pulse signal supply line

15 piston

16 storage container

17 nozzle

18 compressed gas supply line

19 discharge pulse

20 pause pulse

21 third coating zone

Full length of L coating pattern

X₁Length of the first coating zone

X₂Length of the second coating zone

X₁' Length of first coating region after correction

X₂' Length of second coating region after correction

D₂The discharge rate of the second coating region is set to 1.

Detailed Description

An example of an embodiment for carrying out the present invention will be described below with reference to fig. 2 and 3.

[1] Production of coating patterns

The coating pattern for performing the linear coating is formed in consideration of the coating amount and the coating length determined by the shape of the work (chip). The "coating amount" herein means the amount of the liquid material necessary for coating the pattern, and the "coating length" means the total length of the relative movement amount of the nozzle and the workpiece.

The coating pattern is made up of a succession of "coating zones". For each application region, a plurality of pulse combinations (hereinafter referred to as "discharge periods") in which the number of discharge pulses and the number of pause pulses are combined at a predetermined ratio are prepared, and discharge is performed in accordance with the plurality of discharge periods.

In fig. 2, a first discharge period in which a discharge pulse and a pause pulse are combined at a first ratio and a second discharge period in which a discharge pulse and a pause pulse are combined at a second ratio are formed, and a coating pattern is formed by one first coating region 5 in which discharge corresponding to the first discharge period is performed and second coating regions 6 and 6 in which discharge corresponding to the second discharge period is performed being connected to both ends thereof.

In the example of fig. 2, the application regions 6, 6 are made to correspond to the second discharge cycle, but the present invention is not limited thereto, and one of the application regions 6 may be made to correspond to the second discharge cycle and the other may be made to correspond to the third discharge cycle. The number of application regions allocated to one discharge cycle can be set to an arbitrary number.

First, the amount of liquid material (weight or volume) necessary for a desired coating pattern is determined. Then, the lengths of the first coating area 5 and the second coating area 6 are designed according to the coating amount. The pulse combination ratio of each of the first coating region 5 and the second coating region 6 is determined in accordance with a coating pattern having a corner portion, a degree of penetration into a gap, and the like. In this way, stable coating with a constant width can be performed without changing the moving speed.

The chip may be formed along two, three, or the entire periphery of the chip, not only along one side of the chip. The workpiece is not limited to a square shape, and may be a circular shape or a polygonal shape.

A pulse signal composed of a discharge pulse and a pause pulse is transmitted at a predetermined frequency. In principle the frequency corresponds to the number of triggers/second. The frequency is preferably several tens of hertz or more, and more preferably several hundreds of hertz.

[2] Setting of initial parameters

The initial parameters set the number of ejection pulses and the number of pause pulses for each ejection cycle. A setting table in which combinations of the number of discharge pulses and the number of pause pulses are specified is stored in advance in a control unit. Hereinafter, a method of setting the number of discharge pulses and the number of pause pulses in one discharge cycle will be described.

Table 1 shows an example of a setting table stored in the control unit. In table 1, setting example a shows an example of setting the ejection rate when the total pulse number is 100, setting example B shows an example of setting the ejection rate when the total pulse number is 111, and setting example C shows an example of setting the ejection rate when the total pulse number is 125. In setting A, B, C, the number of ejection pulses corresponds to the ejection volume, and the ejection volume can be adjusted by pulse number adjustment by increasing or decreasing the number of pause pulses in the total number of pulses.

The setting example a is a setting example in which the discharge amount is changed based on a combination in which the pause pulse is not set for one discharge pulse (0 pause pulses) when the number of discharge pulses is 100.

The setting example B is a setting example in which the discharge amount is changed based on a combination of setting a pause pulse once (11 pause pulses) for nine discharge pulses when the number of discharge pulses becomes 100.

The setting example C is a setting example in which the discharge amount is changed based on a combination of setting one pause pulse (25 pause pulses) for four discharge pulses when the number of discharge pulses becomes 100.

[ Table 1]

When the number of pause pulses is increased or decreased in the correction of the discharge amount by the adjustment of the number of pulses described later, it is preferable to set the initial parameters so that the timing of the pause pulses becomes equal intervals.

When setting the initial parameters, it is preferable to perform the adjustment from a combination including a pause pulse, rather than from a combination including no pause pulse (i.e., a combination in which the number of pause pulses is 0). In other words, the setting of one or more parameters of the pause pulse can cope with both the case where the discharge amount needs to be increased and the case where the discharge amount needs to be decreased.

When the combination of the discharge pulse and the pause pulse is set, the combination of the discharge pulse and the pause pulse is selected from the stored setting table in accordance with the necessary discharge amount of the desired coating pattern. For example, when considering the coating pattern as shown in fig. 2, if the discharge amount of the first coating region 5 is set to be larger than that of the second coating region 6, a combination of 1 pause pulse (80% discharge) among 4 discharge pulses is selected and set in the first coating region 5, and a combination of 1 pause pulse (75% discharge) among 3 discharge pulses is selected and set in the second coating region 6, in the setting example a of table 1.

[3] Setting of correction period

A correction cycle, which is a cycle for correcting the discharge amount, is set. The correction cycle is set, for example, time information input by a user, the number of chips or substrates, and the like. When the predetermined time is set, the time is set in such a manner that the change in the discharge amount of the liquid material is expected to exceed the allowable range from the start of the operation. When the number of pieces is set, the number of pieces to be processed is determined from the time of processing one chip or the time of processing one substrate (the time of carrying in → coating → carrying out), and the predetermined time.

In setting the correction period, it is preferable that the relationship between the application pattern and the appropriate weight and/or the appropriate discharge time be calculated from a predetermined test with respect to the liquid material used for application, and these values be reflected in the correction period. Although there are also the effects of a change in viscosity of the liquid material due to a change in temperature and the effects of clogging of the discharge portion and a head difference, setting these parameters can be applied to a full-scale change in the discharge amount.

Further, as the limit value of the usage time of the liquid material, a value calculated from the effective time specified by the manufacturer may be stored in advance and combined in the correction cycle.

In the correction cycle setting, it is necessary to consider the viscosity change of the liquid material caused by the passage of time or the change in temperature, but the following description will be made on the premise that the viscosity change is derived only with the passage of time.

In addition, the conventional technique of controlling the viscosity of the liquid material by adjusting the temperature of the discharge portion can be used in the present invention.

[4] Calculation of correction amount

In the set correction period, a correction amount for a change in the discharge amount due to a change in the viscosity of the liquid material is calculated.

The correction amount is calculated by the following method: (A) a method of measuring the weight of the liquid discharged for a predetermined time and calculating the correction amount based on the difference from the appropriate weight; (B) a method of measuring the discharge time required until the weight becomes an appropriate weight and calculating the correction amount based on the difference from the previous discharge time. The present invention can employ any technique, but the following description will be made of a specific procedure for calculating the correction amount based on the technique (a).

[i] Adjustment of pulse number

First, the nozzle (i.e., the discharge device) is moved upward with respect to the weight scale, and the liquid material is discharged at a fixed position. The discharge of the weight meter is continuously performed during the calculated appropriate discharge time. The appropriate discharge time is obtained by calculating an initial setting parameter including a discharge pulse and a pause pulse from an appropriate discharge amount obtained by discharging an appropriate coating length at an appropriate coating speed.

Then, the weight G of the liquid material discharged to the weight meter is read₁. Measuring the weight G from the meter₁With an appropriate weight G₀The rate of change R (═ G) was calculated₁-G₀)/G₀X 100) to obtain the current discharge amount V in the correction period_t. When the rate of change R is negative, the discharge amount V in the appropriate discharge time is set to_tSince the weight is less than the appropriate weight, the setting in which the discharge amount corresponding to the change rate R is increased by the weight is selected from the setting table stored in the control unit, and the number of the discharge pulses and the pause pulses after the correction is set. Conversely, when the rate of change R is positive, the discharge time is appropriateDischarge amount of (V)_tSince the discharge amount is larger than the appropriate amount, the setting in which the discharge amount corresponding to the change rate R is weighted by the reduced amount is selected from the setting table stored in the control unit, and the number of the discharge pulses and pause pulses after correction is set.

Further, the weight may be measured a plurality of times and then averaged. Thus, the measured value can be obtained with higher accuracy.

[ ii ] adjustment of discharge cycle switching position

The discharge amount correction may be performed by adjusting the pulse number in [ i ] or by individually adjusting and switching the positions of the plurality of discharge cycles set in [1 ]. Here, the "adjustment of the switching position of the discharge cycle" is performed without changing the discharge amount per unit time in each discharge cycle with respect to the length of the application region corresponding to one discharge cycle and the length of the application region corresponding to another one or more discharge cycles. The correction by the adjustment of the discharge cycle switching position can be performed in a finer manner than the correction of [ i ], and the correction accuracy can be further improved by performing the correction alone or after the correction of [ i ]. The reason is that although there may be a portion where an offset occurs in the correction performed by the adjustment of the number of pulses belonging to the digital expression, in the case of the period switching position adjustment belonging to the analog expression, the correction may be performed without an offset in the portion.

The description will be given with reference to fig. 3 based on the example shown in fig. 2.

First, the discharge weight was measured in the same manner as in [ i ]. As will be described later, the correction procedure may be performed without performing the measurement and the result of [ i ] may be used, or the measurement and correction may be performed again.

First, from the measured weight (measured coating weight) G₁In the method, the discharge weight G per unit length is obtained_d. Measuring weight G₁Corresponds to that shown in FIG. 3(b)Convex portion S surrounded by oblique lines in the figure₁The area of (a). Specifically, the discharge amount G per unit length of the 1 st coating region is set to_dMultiplied by the length X of the first coated area₁The portion (corresponding to the symbol 5) and the discharge amount G per unit length of the second coating region_dD₂Multiplied by the total length (L-X) of the second coating zone₁) The area of (c) is added to the area of (d) (corresponding to reference numeral 6). Here, L is the total length of the coating pattern, X₁Is the length of the first coating region before correction, D₂The discharge rate of the second application region is set to 1. Therefore, the weight G is measured₁The following calculation was made:

[ formula 1]

G₁＝X₁G_d+(L-X₁)D₂G_d

Therefore, the discharge weight G per unit length_dThe following calculation was made:

[ formula 2]

Second, the discharge weight G per unit length obtained from equations 1 and 2_dAnd an appropriate weight (appropriate coating weight) G calculated by the following formula₀Calculating the length of the first coating region after correctionDegree X₁'. Appropriate weight G₀The area S of a convex portion surrounded by oblique lines in the graph shown in FIG. 3(c) is set as₀. In this case, the discharge weight G per unit length is not changed_dAnd the ratio D of the discharge amount of the second coating region₂In the case of (2), the discharge of an appropriate weight G is performed₀The length of each application region must be changed for the correction of (2). If the length of the first coating region after being changed is X₁', by the same method as in the above formula 1, the weight G is appropriately set₀The following calculation was made:

[ formula 3]

G₀＝X₁′G_d+(L-X₁′)D₂G_d

Therefore, the corrected length X of the first coating region₁' the following equation is calculated:

[ formula 4]

In addition, the length X of the second coating region after correction₂' is from the total length L of the coating pattern, minusLength X of the first coating region after correction₁'. In the example of fig. 3, the length X of the first coating region after correction is subtracted from the overall length L of the coating pattern₁' value, 2 equivalences and set as X₂′。

Finally, the coating pattern changed to the length of the first coating region and the second coating region after the correction obtained above is set as a new coating pattern.

Similarly, the weight may be measured a plurality of times and then averaged. Thus, a measurement value with better accuracy can be obtained.

[5] Execution of corrections

When the above [4] determines that the correction of the discharge amount is necessary, the pulse number is adjusted in the above [ i ] and then the correction is performed by adjusting the position in the above [ ii ] discharge cycle.

Here, whether or not the discharge amount correction is necessary is determined, and it is preferable that the correction is performed only when the difference in the measured discharge amount (measured value) or the change rate exceeds an allowable range (for example, ± 5%) without performing the correction normally when there is no weight difference or the change rate is zero. A preferable mode of the correction for setting the allowable range is described in detail in, for example, japanese patent No. 3877038 filed by the applicant of the present application. That is, the allowable range for determining whether or not to perform the correction is designed, and the coating pattern is corrected only when the difference or the change rate exceeds the allowable range.

As described above, the steps of [4] and [5] can be performed in the correction cycle set in [3], or in the case where the type (size or shape) of the substrate is changed, or the like, so that an optimum amount of coating can be always achieved regardless of the change in the viscosity of the liquid material with time. Further, since the correction by the adjustment of the pulse number of [ i ] of [4] is suitable for the correction with a large width and the correction by the adjustment of the discharge cycle switching position of [ ii ] of [4] is suitable for the correction with a small width, the correction accuracy can be further improved by performing the adjustment of [ ii ] of [4] after the adjustment of [ i ] of [4 ].

According to the correction of the present invention described above, since it is not necessary to change the discharge conditions (for example, stroke, nozzle temperature, etc.) for determining the discharge amount for each trigger, the calculation of the correction is simple, and there is no problem of variation in the discharge amount caused by changing the discharge conditions, so that the correction can be performed with high predictability.

The present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1

[1] Coating device

The coating apparatus 8 of the present embodiment is, for example, a coating apparatus used in the underfill process, and as shown in fig. 4, includes: a discharge device 13, an XY drive mechanism 9, a weight scale 10 as a measuring section, a conveying mechanism 11, and a control section 12 for controlling these operations.

The discharge device 13 is of a jet type and has a nozzle 17 for discharging the liquid material 4. The discharge device 13 is mounted on the XY drive mechanism 9 and is movable above the substrate 2 and above the weight scale 10.

The XY drive mechanism 9 can perform an operation of applying the liquid material 4 in a desired pattern while moving in the XY direction above the substrate 2.

When the coating is started, the flip chip mounted substrate 2 as a coating object is first conveyed to a position below the discharge device 13 by the conveying mechanism 11.

The coating by the discharge device 13 is started after the substrate 2 is transported to a position below the nozzle 17 and the substrate 2 is positioned. The trajectory of the coating operation of the nozzle 17 (i.e., the basic coating pattern) is stored in advance in a memory or the like in the control unit 12.

When the coating is completed, the substrate 2 is carried out of the coating apparatus 8 by the carrying mechanism 11. Subsequently, the next substrate 2 is carried in and the coating operation is repeated. In this case, the carrying in, the coating, and the carrying out are one step, and the coating operation is repeated until the coating of the required number of substrates 2 is completed.

During the repetition of the above steps, the discharge amount is corrected at a timing of a predetermined correction cycle. That is, correction of the discharge amount that is derived from a change in the viscosity of the liquid material 4 is performed. The correction amount is calculated by moving the nozzle 17 above the weight scale 10 by the XY drive mechanism 9 and measuring the weight of the liquid material 4 by the weight scale 10. The correction procedure will be described in detail later.

[2] Discharge device

As shown in fig. 5, the discharge device 13 includes: a piston 15 connected to the piston so as to be movable vertically, a reservoir 16 pressurized by a compressed gas regulated by a compressed gas supply line 18, and a nozzle 17 communicating with the reservoir 16.

The liquid material 4 filled in the reservoir 16 is discharged in the form of droplets from the nozzle 17 by moving the piston 15 up and down in accordance with the pulse signals (19, 20) transmitted from the control unit 12 through the pulse signal supply line 14. The liquid material 4 discharged from the nozzle 17 is applied to the substrate 2, the weight scale 10, and the like positioned below the nozzle 17. Here, the storage container 16 is pressurized by the compressed gas supplied from the control section 12 via the compressed gas supply line 18 and pressure-regulated.

The discharge device 13 discharges one droplet of the liquid material 4 from the nozzle 17 by reciprocating the piston 15 one time for one pulse signal. That is, a unit period formed by one pulse signal corresponds to one trigger.

The pulse signals (19, 20) are applied as shown in fig. 6, for example, and when the pulse signal is on, the piston 15 is raised to open the nozzle opening, and when the pulse signal is off, the piston 15 is lowered to close the nozzle opening. Then, the rise of the piston 15 (opening of the nozzle opening) and the fall of the piston 15 (closing of the nozzle opening) are set as a unit cycle, and a droplet of the liquid material is discharged in the operation of the unit cycle (reference numeral 19 in fig. 6). On the other hand, when the pulse signal is off, the piston 15 does not operate, and the nozzle opening is closed for one unit period (reference numeral 20 in fig. 6).

In addition, the time of the on state (rising time) and the time of the off state (falling time) in one unit cycle may be adjusted.

When coating is performed along the edge of the workpiece, the control unit 12 sends pulse signals (19, 20) to the discharge device 13 at a predetermined frequency while moving the nozzle 17 at the same time as the start of coating, and continuously discharges the liquid material 4. The liquid material 4 discharged along the edge of the work fills the gap between the work 1 and the substrate 2 by capillary action.

The frequency setting of the pulse signals (19, 20) transmitted by the discharge device 13 is performed in accordance with the mechanical response characteristics of the discharge device 13 and the characteristics of the liquid material 4. The optimum frequency varies depending on the discharge rate, and is usually about 100 to 200 Hz.

If the frequency is changed, the discharge amount and the like are also changed, but the discharge amount does not have a linear change characteristic with respect to the frequency change, and may not be ejected depending on the conditions. Therefore, when the discharge amount is corrected in the coating operation of the same coating pattern, it is preferable that the frequency be set without changing. That is, the present embodiment is characterized in that: the discharge amount is corrected by adjusting the ratio of the discharge pulse to the pause pulse, and the discharge amount is corrected not in accordance with the change in the frequency of the pulse signal.

[3] Correction sequence by pulse number adjustment

Fig. 7 is a flowchart illustrating a correction procedure by pulse number adjustment according to the present embodiment.

First, when a set correction cycle is reached, discharge is performed by transmitting a plurality of pulses including a discharge pulse and a pause pulse for an appropriate discharge time from an appropriate discharge time obtained from an appropriate coating length and an appropriate coating speed (step 11). Then, the weight G of the discharged liquid material was measured₁(step 12). Then, the appropriate weight G₀And measuring the weight G₁And comparing (step 13), and judging whether correction is needed or not by using whether the weight difference exceeds the allowable range or not (step 14).

If it is determined in step 14 that correction is necessary, the weight G is adjusted from the appropriate weight₀And measuring the weight G₁The rate of change R (═ G) was calculated₁-G₀)/G₀X 100) (step 15), and the positive or negative of the change rate R is judged (step 16).

If the rate of change R is negative, the discharge amount is less than the appropriate amount, and therefore, a setting in which the discharge amount corresponding to the rate of change is increased by a weight is selected from the table stored in the control unit, and the values of the discharge pulse and the pause pulse are set again (step 17).

If the rate of change R is positive, the discharge amount is greater than the appropriate amount, and therefore, a setting in which the discharge amount corresponding to the rate of change is reduced by a weight is selected from the table stored in the control unit, and the values of the discharge pulse and the pause pulse are set again (step 18). If the setting is finished, the coating is executed (step 19).

As a variation of the above-described correction procedure, the presence or absence of correction may be determined by setting the allowable range at a change rate, instead of setting the allowable range at the weight difference. In this case, the determination is performed between step 15 and step 16 without performing step 14.

[4] Correction sequence by switching position adjustment in discharge cycle

Fig. 8 is a flowchart illustrating a correction procedure performed by switching the position adjustment in the ejection cycle according to the present embodiment.

First, if it is, thenAt the set correction cycle, discharge is performed for a proper discharge time determined from the proper coating length and the proper coating speed (step 21). Then, the weight G of the discharged liquid material was measured₁(step 22). Then, the appropriate weight G is compared₀And measuring the weight G₁(step 23) it is determined whether or not correction is necessary by using whether or not the weight difference exceeds the allowable range (step 24).

When it is determined in step 24 that correction is necessary, the lengths of the plurality of application areas are calculated (step 25), and the length of each application area in the application pattern is set again based on the calculated lengths (step 26). If the setting is finished, the coating is executed (step 27).

As a variation of the above-described correction procedure, the presence or absence of correction may be determined by comparing the allowable range with any of the lengths of the respective application regions, without using the weight difference. In this case, the determination is performed between step 25 and step 26 without performing step 24.

Further, the above-mentioned [3] and [4] may be performed continuously. In this case, even if a portion that cannot be corrected by [3] remains, the correction can be continued by [4 ]. Conversely, the sequence from step 21 to step 24 in [4] may not be performed, but the results from step 11 to step 14 in [3] above may be used. Further, the step 18 of [3] above may be executed first, and the step after the step 25 of [4] may be executed next. Thus, the time required for the correction operation can be shortened.

According to the device of the present embodiment described above, by storing the predetermined adjustment ratio (setting table) calculated in advance, adjustment can be performed without considering the properties of the liquid material and the like. Further, by switching a plurality of different discharge cycles in the middle of the application pattern, the fillet shape can be maintained in a stable state even if the workpiece shape or the penetration rate into the gap is different. Further, by adjusting the position at which the plurality of different discharge cycles are switched in addition to the adjustment of the number of pulses, the correction accuracy can be further improved, and a certain amount of discharge can be performed more precisely.

Example 2

[ variation of correction amount calculation ]

In the embodiment, the discharge weight G per unit length is obtained_dAfter that, the corrected length of each application region is obtained again, but the corrected length of each application region may be obtained from the number of times of discharge per unit time, the moving speed of the discharge device, and the discharge weight of one trigger. The details are as follows. In addition, the coating pattern is the same as in fig. 3.

First, discharge is performed for an appropriate discharge time determined from an appropriate coating length and an appropriate coating speed, and the weight G of the discharged liquid material is measured₁. Measuring the weight G from the meter₁The discharge amount w per one trigger is obtained. First, if the number of times of discharge per unit time Y of the first application region is known₁And the number of times of discharge per unit time Y of the second coating region₂And the moving speed V of the discharge device, and then the weight G is measured₁The following equation is calculated:

[ formula 5]

Here, L is the total length of the coating pattern, X₁Is the length of the first coated region. Therefore, each timeThe triggered discharge amount w is calculated by the following equation:

[ formula 6]

The number of times Y of discharge per unit time of each application region is not changed in order to obtain the discharge amount w per one shot₁、Y₂In the case of (3), a proper weight G is discharged₀The length of each coating area must be changed. If the length of the first coating region after being changed is X₁', then the appropriate weight G₀It is represented by the following formula:

[ formula 7]

Therefore, the corrected length X of the first coating region₁' the following equation is calculated:

[ formula 8]

In addition, the length X of the second coating region after correction₂' is to subtract the corrected length X of the first coating region from the total length L of the coating pattern₁' and setting a new coating pattern to be changed to the length of the first coating region and the second coating region after the correction obtained above, as a new coating pattern, similarly to the above-described embodiment.

In addition, when the discharge weight is obtained, the weight at the time of discharge is measured by a predetermined number of triggers, and the discharge amount per trigger is obtained from the measured weight and the number of triggers, instead of equations 5 and 6.

The weight may be measured several times and then averaged. Thus, a measurement value with better accuracy can be obtained.

Example 3

[ other coating Pattern case 1]

Fig. 9 shows an application pattern in the case of applying the coating in an L-shape along the outer periphery of the work 1. In this example, the first coating regions 5 are formed in the vicinity of the centers of the two sides to be coated, respectively, the second coating regions 6 are formed in the vicinity of the corners where the two sides join each other, and the third coating regions 21 are formed at the opposite ends of the second coating regions 6, respectively. The first to third coating regions 5 to 21 correspond to the first to third discharge cycles. At this time, the liquid material is likely to be retained at the corner portion due to the liquid material permeating from both directions, the direction change, and the like. Therefore, by setting the second discharge cycle to a pulse combination with a smaller discharge amount than in the other discharge cycles, the liquid material can be prevented from staying at the corner portions, and a fillet with a constant width can be formed. The same calculation method as in embodiments 1 and 2 described above can be applied to the calculation method of the correction amount.

In the case of fig. 9, the adjustment of the discharge cycle switching position can be performed at a plurality of positions, but at which position the adjustment is performed, the optimum position is appropriately determined in accordance with the shape of the workpiece 1, the mounting position of the workpiece 1 on the substrate, the arrangement density of the protruding electrodes (hereinafter referred to as "bumps"), and the like. For example, when the bump arrangement density is changed at the switching position by adjusting the discharge cycle switching position, it is preferable to select a region where the bump arrangement density is not changed and perform the correction. In consideration of such conditions, the area where the expansion and contraction is performed is determined so that the application shape (fillet shape) does not collapse. The calculation of the correction amount is studied in principle in units of one stroke (nozzle lowering → coating → nozzle raising), but the present invention can be sufficiently applied when a plurality of overlapping coatings are applied at the same place (when two or more coatings are applied).

Example 4

[ other coating Pattern case 2]

When the work (chip) 1 is small and the like and can be completed with a small filling amount, the coating length is also shortened (when the filling amount is small, the side to be coated is often completed while being coated). In this case, since a small correction amount can be almost completed, the correction by the "adjustment of the discharge cycle switching position" shown in embodiment [4] [ ii ] can be performed alone.

As described above, although fine correction can be performed by the correction performed by "adjustment of the discharge cycle switching position", when the correction amount is large, a large difference must be given in each discharge cycle period in advance, and the application shape (mainly the line width) is affected, which is not an optimal means. However, when a small correction amount can be completed, it is possible to sufficiently cope with the correction by "adjustment of the discharge cycle switching position", and it is naturally preferable from the viewpoint of accuracy. Further, by performing the correction by "adjustment of the discharge cycle switching position" alone, there is also an advantage that the time taken for the correction is shortened.

In this procedure, after the discharge weight is roughly measured and whether or not the correction is performed is determined, when the correction is necessary, the length of the application region is calculated in the same manner as described above, and the application pattern is reset. That is, the present invention is implemented in accordance with the procedures described in the flowcharts of the embodiments [4] [ ii ], examples 1[4], and "fig. 8".

In this example, when the length of the coating pattern was 1cm, the correction was performed in the above-described order, and as a result, a good correction result was obtained.

(availability in industry)

The present invention may be implemented in various devices for discharging liquid materials. For example, as a discharge mode of a mode in which the liquid material is brought into contact with the work after being separated from the discharge device, there may be: a jet type in which a valve body is caused to collide with a valve seat to thereby cause a liquid material to be scattered and discharged from a tip of a nozzle; a plunger jet type in which a plunger is moved, then abruptly stopped, and similarly ejected from a nozzle tip; and an ink jet type of a continuous ejection type or a random ejection type.

Claims (8)

1. A method for filling a liquid material discharged from a discharge device into a gap between a substrate and a work placed thereon by utilizing a capillary phenomenon, the method comprising:

a step of forming a coating pattern composed of a plurality of continuous coating regions;

a discharge cycle allocation step of allocating a plurality of discharge cycles in which the number of discharge pulses and the number of pause pulses are combined at a predetermined ratio to each application region; and

a correction amount calculation step of measuring a discharge amount from the discharge device at a time of the correction period in a preset correction period and calculating a correction amount of the discharge amount;

the method further includes a discharge amount correction step including:

adjusting the number of the discharge pulses and the number of pause pulses included in the coating pattern based on the correction amount calculated in the correction amount calculating step; and/or adjusting the length of at least the first coating region and the other one or two coating regions continuous with the first coating region without changing the discharge amount per unit time in each coating region.

2. The method for filling a liquid material according to claim 1, wherein in the discharge cycle distribution step, the discharge cycle includes a discharge cycle to which the multi-application regions are distributed.

3. The method for filling a liquid material according to claim 1 or 2, wherein in the correction amount calculating step, the correction amount of the discharge amount is calculated based on a difference between a measured value of the weight of the liquid material discharged for a certain period of time and a theoretical value of the certain period of time.

4. The method for filling a liquid material according to claim 1 or 2, wherein in the correction amount calculating step, the correction amount of the discharge amount is calculated based on: a measured value of the weight of the liquid material discharged for a certain period of time; a theoretical value for the certain time; the length of each coated area; and a ratio of a discharge amount of any one of the application regions to a reference amount of the other one or two continuous application regions, when the discharge amount of the one of the application regions is set as the reference amount.

5. The method of filling a liquid material according to claim 1 or 2, wherein in the discharge amount correction step, the correction of the discharge amount is performed without changing the frequency of transmitting the discharge pulse and the pause pulse.

6. The method for filling a liquid material according to claim 1 or 2, wherein an allowable range for determining whether or not to perform correction is set in a step before the correction amount calculation step, and correction is performed when the allowable range is exceeded.

7. The method for filling a liquid material according to claim 1 or 2, wherein the correction cycle is set based on time information, the number of pieces of work, or the number of pieces of substrates, which is input as the correction cycle by a user.

8. The method of filling a liquid material according to claim 1 or 2, wherein in the discharge amount correction step, the correction of the discharge amount is performed without changing a relative movement speed of the discharge device and the workpiece and an overall length of the application pattern.