JP2614741B2 - Thermo Mode Tool for Tab Bonding and Tab Bonding Method Using the Thermo Mode Tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION I) Industrial Field of the Invention The present invention relates to positioning and equilibrium contact of a tape lead to a pattern on a substrate with micro-precision precision, and bonding, adjusting, pressing and heating. The present invention relates to a thermo bonding tool for tab bonding and a tab bonding method using the tool.

II) Object of the present invention (1) At present, as a method of bonding (welding) a chip (mainly a semiconductor) to a pattern of a substrate (mainly, PCB = print circuit board, IC card, etc.), a wire is used. Bonding and tab bonding (tab = TAB = tape automated bonding) are generally performed.

Wire bonding is limited to a pitch of 100 μm between leads, and the number of leads is about 125 to 250.
Those with 500 or more) are considered impossible without tab bonding.

As is well known, tab bonding forms a lead on a tape (film) by printing and etching, bonds a chip to an inner lead of the tape (ILB = inner lead bonder), and attaches an outer lead to a substrate. Bonding to pattern (OLB
= Outer lead bonder). (See FIGS. 3 and 4.) (2) In the present invention, in bonding the leads (outer leads) of the tape to the pattern of the substrate in the OLB process, heating the leads of the tape, that is, the thermode tool that has absorbed the tape. A thermode tool for tab bonding, and a tab by the tool, which enable extremely high-precision bonding by positioning and equilibrium abutment of the part so as to conform to the pattern of the substrate ultra-precisely, and evenly adjusting and pressing. A bonding method was developed.

III) Problems in the prior art (1) Heating the thermode tool that bonded the chip to the inner lead of the tape (the above-mentioned ILB) and cut and formed the outer lead (hereinafter abbreviated as tape) When the part is positioned and abutted against the pattern on the board, and then bonded by heating under pressure, even if the lead of the tape of the heating part and the pattern of the board are precisely aligned in advance by optical means, both are precisely in the horizontal plane. It is very unlikely that there is a slight inclination error between the two when they come into contact with each other. Therefore, when the heating part is brought into contact with and pressed as it is, a misalignment occurs between the lead and the pattern. Partial strength unevenness occurs.

As described above, the pitch between the leads of the tape is, for example, as small as 50 μm or less, so that even when the position is minutely shifted, the lead and the pattern are not connected, or an error occurs in which the lead is erroneously connected to an adjacent lead. However, non-welding, incomplete welding, fusing due to excessive pressurization, and the like occur depending on uneven pressure.

Therefore, even if one connection error or welding failure occurs, the whole product is defective, so the above is a very serious problem.
Therefore, in order to perform accurate tab bonding, extremely accurate positioning and equilibrium contact (average surface contact), and adjustment pressurization (even and uniform pressurization) are imposed as stringent conditions that must be cleared. However, none of the conventional devices and methods could clear this.

V) Configuration and Method of the Present Invention The present invention effectively solves the above conventional problems.

(1) That is, the present invention provides a tool body having a rectangular heating portion for suction-holding a tape at a lower end thereof and pressing and bonding a lead of the tape to a pattern of a substrate by pressing and heating, and mounting a ball on a vertical axis center line at an upper end. Into the through hole in the center of the holder on the lower surface plane so as to be slidable up and down. The holder is slidably supported by a plurality of balls that are in point contact with the lower surface of the holder, and its two parallel sides in the X direction are The parallel guide is slidably engaged in the X direction, and the engagement between the two parallel sides and the parallel guide is
Set up the holder so that it will come off when slightly raised,
This is a thermoelectric tool for tab bonding, in which a stopper surface is provided above a ball at an upper end of a tool main body and a substrate is provided below a heating section at a lower end so as to be vertically movable as required.

(2) Further, according to the present invention, the pattern of the tape lead and the substrate sucked and held by the heating part of the thermod tool is precisely positioned at a relative position vertically separated by optical means or the like, and then the heating part and the substrate are contacted. (I) First, one corner of the square heating part of the thermode tool is brought into point contact with a set point on the substrate, (ii), and then (ii) (Iii) Finally, by bringing the continuous surface (entire surface) into surface contact with the line, the heating portion, that is, the tape lead sucked and held there, is brought into contact with the line. Positioning and equilibrium contact of substrate pattern (average surface contact)
The heating part of the positioning and equilibrium contacted thermode tool is adjusted, pressurized and heated to the substrate, and each lead is bonded to the pattern.
This is a bonding method using a thermode tool.

(3) Next, the configuration of the thermomode tool of the present invention will be described with reference to an embodiment. A tape T is sucked and held at the lower end, and its lead L is attached to the substrate P.
The tool body 1 provided with a square heating section 2 for pressure-bonding and heating bonding to the pattern of FIG. The holder 4 is tightly inserted into a through hole 10 formed in the center of the holder 4 so as to be slidable up and down, and the holder 4 is connected to four balls 5 (screw 6
Slidably supported by a steel ball fixed or rotatably attached to the end of the holder 4, and the parallel two sides 7, 7 in the X direction of the holder 4 are slidable in the X direction by parallel guides 8, 8. So that the two parallel sides 7, 7 and the parallel guides 8, 8 are still disengaged when the holder 4 is slightly raised (eg, about 0.5 mm). A stopper surface 9 is provided above the ball 3 at the upper end of the tool body 1.
And a substrate P below the lower end of the heating unit 2, respectively.
The thermode tool S is configured to be freely movable up and down as necessary. (See FIG. 1) (4) In the present invention, the rotation of the heating part 2 of the thermode tool S from the point a ₁ contact position at one corner to the line a ₂ contact position in the X direction, Point a _{1 With the} contact position as a fulcrum, the holder 4 is rotated in the X direction by the sliding between the holder 4 and the four balls 5 that are in point contact with the lower surface thereof, and simultaneously rotated in the Y direction to θ
The parallel two sides 7, 7 of the holder 4 are provided so as to be guided in the X direction by the parallel guides 8, 8, so that no displacement occurs.

(5) Further, the rotation of the heating section 2 of the thermode tool S from the contact position on the line a _{2 in} the X direction to the contact position on the surface a _{3 in the} Y direction,
The two parallel sides 7, 7 of the holder 4 are removed from the parallel guides 8, 8, for example, by slightly lifting the holder 4, and the holder (+ tool main body 1) is set free so as to perform the heating. 2 is provided so that the entire surface thereof comes into equilibrium contact with the substrate (average surface contact without positional unevenness).

(6) Further, the ball 3 at the upper end of the thermode tool S
However, for example, it comes into point contact with the descending stopper surface 9,
When the true center of the ball 3 is pressurized, the heating unit 2 that is in equilibrium contact with the substrate P as described above is partially pressurized and adjusted to a state where there is no variation in strength, and bonding is performed. Things.

V) Action The present invention provides tab bonding, that is, ultra-precise positioning and equilibrium contact (average surface) between the heating portion of the thermode tool (that is, the lead of the tape sucked and held there) and the substrate (pattern). Contact), adjustment pressurization (uniform pressurization) in the equilibrium contact state, and heat bonding, and a tab bonding method using the thermostat tool. Method).

Normally, when the heating section 2 of the thermode tool S is positioned and brought into contact with the substrate P, it is impossible that the heating section 2 exactly matches from the beginning with an accuracy of a micron unit. It shifts to contact.

However, when the point contact is immediately shifted to the surface contact as in the related art, a θ shift always occurs.
A shift of 5 μ at one corner symmetrical to the corner would lead to erroneous lead connection.

(1)... Therefore, according to the present invention, the substrate P is moved upward, and first, one corner of the heating section 2 is always brought into contact with the set point of the substrate at a point a ₁ . (Figure 2, (a)) (2) ... Then, when raised slightly by the substrate P, both transitions St. to surface contact, skid to its own weight point a ₁ contact position by Sir mode tool S at the same time ( position shift) but tends to St. occurs, because of the holder 4 lower surface which closely fitting insert the tool body 1 into four very slipperiness good conditions in point-contact support of the ball 5, the contact resistance of the point a ₁ The force acts on the point contact position between the ball 5 and the holder 4 and the holder 4 (+
The tool body 1) slides and turns.

(3)... The present invention restricts the sliding rotation of the holder 4 in the X direction (when the rotation in the Y direction occurs simultaneously and θ
Parallel 2 in the X direction of the holder 4
Since receiving sides 7,7 in parallel guide 8,8, the holder 4 (+ tool body 1) is rotated in the X-direction the point a ₁ as the fulcrum, is continuous in the point a ₁ of the heating unit 2 X One side of the direction is line a ₂
Contact. (Figure 2, when the slightly raised (i) → (ii) (4) ... Then, the line a ₂ substrate in contact P and the tool body 1 (+ holder 4), the holder 4
Two parallel sides 7, 7 is disengaged from the parallel guides 8, 8, also spaced apart ball 5 both tool body 1 (+ holder 4) becomes a free state, therefore, automatically from a line a ₂ contact one side to be rotated in the Y direction of the surface a _3-contact, the heating unit 2 and the substrate P is equilibrium abutment (positional unevenness-free average surface contact).
(FIG. 2, (c) → (e)) As described above, the pattern of the lead L of the tape T and the pattern of the substrate P sucked and held by the heating unit 2 were positioned and brought into equilibrium contact without any displacement of 1 micron. Becomes

(5) ... Finally, the stopper surface 9 descends and presses in point contact with the ball 3 at the upper end of the thermode tool in the above state, and the pressing force is adjusted and pressurized on the entire heating section on average. , The leads of the tape and the patterns of the substrate are all bonded evenly.

(6) ... embodiment, when one corner of the heating unit 2 is in point contact with the substrate, the angle between one side and the substrate in the X-direction continuous with the point a ₁ is within 0.35 to 0.5 ° (except Example Tape Is a 15mm square,
In the case of about 500 leads and a pitch between leads of about 50 μm), pressure bonding was performed in the above-mentioned positioning equilibrium contact state, and no deviation of 1 μm occurred between each lead and the pattern.

(7) In the above (1) to (3), the tool body + holder is lowered instead of raising the substrate, and the substrate and tool body +
The parallel guide may be lowered instead of raising the holder, and the substrate and the tool body may be raised instead of lowering the stopper surface in item (5).

(8) ... Also, a line contact is made from the point contact in the Y direction, and then X
Surface contact in the direction is also possible.

VI) Effect (1) As described above, according to the present invention, the heating part (that is, the lead of the tape) of the thermod tool is super-precisely positioned on the substrate (pattern), is brought into equilibrium contact, and is adjusted and pressed. When bonding, make sure that the first corner of the heating section is in point contact with the substrate.
Next, one side continuous to the point is brought into line contact in the X direction, and the action from the point to the line contact is performed by the sliding property of each ball in point contact with the holder and the parallel guide for guiding the holder only in the X direction. So, the point →
It has the feature that X-direction line contact can be performed extremely accurately and smoothly. This prevents the θ shift (Y-direction position shift) that always occurred due to the conventional transition from point contact to surface contact. There is an excellent effect to get.

(2)... Next, the present invention relates to the above-described line contact from one side in the X direction to Y
To the surface contact in the direction, and this is automatically performed when the two parallel sides of the holder are free from the parallel guide, so that there is a risk of displacement from the line contact to the surface contact in the Y direction. Can be performed very naturally without any contact (one side is in line contact and does not deviate due to its contact resistance), which enables ultra-precise positioning of leads and patterns (without 1μ deviation) and partial There is an excellent feature that makes it possible to make balanced surface contact without unevenness (balance contact = average surface contact).

(3) Since the stopper surface makes point contact with the ball at the upper end of the thermode tool where the above-described accurate positioning and equilibrium abutment are completed, the pressure applied to the point increases from the center of the ball to the tool body. The center line of the vertical axis of → is applied to the entire surface of the heating section in equilibrium contact with the substrate, so that an even adjustment pressure is applied without partial variation, and therefore, all the leads and the pattern can be bonded with even precision. There is.

(4) As described above, the present invention can provide an excellent-performance thermobonding tool for tab bonding and a tab bonding method using the tool, which have solved the conventional disadvantages.

[Brief description of the drawings]

FIG. 1A is a front view schematically showing the configuration of an embodiment of a thermode tool of the present invention, FIG. 1B is a side view, and FIG.
(E) is an explanatory view of the method (action) of the present invention, FIG. 3 is a plan view of an ILB in which a chip is bonded to an inner lead of a tape, and FIG. 4 is an OLB in which an outer lead of the ILB is cut and formed (the present invention relates to a substrate). FIG. 3A is a plan view and a side view of an object to be bonded to the substrate. Number S: Thermode tool, T: Tape, L: Lead, P: Substrate, C: Center line of vertical axis, 1 ... Tool body, 2 ... Heating section, 3 ... Ball, 4 …
... Holder, 5 ... Ball, 6 ... Screw, 7, 7 ... 2 parallel sides, 8, 8 ... Parallel guide.

Claims (4)

(57) [Claims] 1. A tool body having a rectangular heating section for adsorbing and holding a tape at its lower end and press-bonding and heating its lead to a pattern on a substrate. The holder is slidably inserted in the through hole at the center of the holder in a vertically slidable manner, and the holder is slidably supported by a plurality of balls in point contact with the lower surface of the holder, and two parallel sides in the X direction are slid in the X direction by a parallel guide. The two parallel sides and the parallel guide are engaged so that they can be disengaged when the holder is slightly raised, and a stopper surface is provided above the ball at the upper end of the tool main body and below the heating section at the lower end. A thermo-tool for tab-bonding, in which the boards are set up and down as required. 2. A pattern of a tape lead and a substrate sucked and held by a heating part of a thermode tool and a pattern of a substrate are precisely positioned at a relative position vertically separated by an optical means or the like. Then, when performing tab bonding for bonding the lead and the pattern, (i) first, one corner of the square heating portion of the thermode tool is brought into point contact with a set point on the substrate; (Iii) Finally, by bringing the surface (whole) continuous with the line into surface contact, the heating unit, that is, the position of the pattern of the tape and the substrate of the tape sucked and held by the heating unit, and the balance of the pattern are adjusted. (Iv) The heating part of the positioning and equilibrium contacted thermostat tool is adjusted and heated to the substrate to bond each lead to the pattern. Characterized in that the tab bonding method according to Sir mode tools tab bonding according to paragraph 1 the claims. 3. The rotation of the heating portion of the thermode tool from a point contact position at one corner to a line contact position in the X direction is performed by using the point contact position as a fulcrum and sliding between the holder and the ball contacting the lower surface thereof at each point. Thus, two parallel sides of the holder are guided in the X direction by parallel guides so that the holder is rotated in the X direction and simultaneously rotated in the Y direction so as not to cause a θ shift. A thermode tool for tab bonding according to claim 1. 4. The rotation of the heating part of the thermode tool from the line contact position in the X direction to the surface contact position in the Y direction is performed by removing two parallel sides of the holder from the parallel guide and setting them free. 2. The thermo bonding tool for tab bonding according to claim 1, wherein the heating unit is provided so that the entire surface of the heating unit is in equilibrium contact with the substrate.