JP3147424B2 - Electronic circuit components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit component.
More specifically, the present invention relates to an IC (semiconductor integrated circuit) chip for chip-on-board mounting, an IC chip for hybrid integrated circuit, various surface mounting (SMT) elements, a lead frame, and a TAB (Tape Automated Bonding) mounting. Electronic parts having bumps such as film carrier tapes and wiring boards (PWB).

[0002]

2. Description of the Related Art In recent years, as the demand for circuit miniaturization has increased, mounting techniques such as a chip-on-board for directly mounting a bare IC chip (bare chip) on a wiring board have been developed. As a connection method in such a chip-on-board or the like, a wire bonding method in which an IC chip and a circuit wiring of a wiring board are connected by a wire, a film carrier tape is used, and leads of the film carrier tape are connected to bumps of the IC chip. TAB method, I
A flip chip method has been developed in which a bump is provided on the upper surface of a C chip, the IC chip is mounted face down on a wiring board, and the bump of the IC chip is connected to a circuit wiring.

[0003] Above all, as the miniaturization and high-density mounting of elements have progressed and the spacing between leads and circuit wirings has been gradually narrowed, mounting methods using bumps have become important. The bonding method using a bump includes the above-described TAB method and flip chip method. For example, in these methods, an Au bump of an IC chip and an electrode pad of Al or the like of a wiring board are overlapped, and these are heated and pressed. Thus, a eutectic alloy such as Au-Al is formed, and the Au bump is
And the like.

[0004]

Conventionally, the bumps are formed by electrochemical plating (wet method), and therefore have a high hardness (Vickers hardness of 80 or more). For this reason, a large pressing force (the pressing force of one bump × the number of bumps) is required to bond a bump such as an IC chip to an electrode pad of a circuit wiring, and a large amount of bonding energy is consumed. The IC chip may be damaged due to cracks or the like due to large internal stress. In particular, as the number of pins of the IC chip increases and the bump interval becomes narrower, the required pressing force increases.
The IC chip is easily damaged. As a result, there is a problem that the reliability of the IC is reduced and the yield of electronic circuits and the like is deteriorated.

In addition, since the formation of bumps is a wet process by electrochemical plating, IC chips (wafers) and the like are easily contaminated with a plating solution, the plating solution is liable to cause pollution, and Au plating is used to an extra place. However, there is a problem that it is not economical, it is necessary to mask a region other than the bump formation region, the process is troublesome, and mass production is low due to a batch process.

Further, if the current flow varies within the wafer of the IC chip, the bump height becomes uneven. Furthermore, since the crystal type of the bump differs depending on the current density, the bump has anisotropic shape (growth), and it is difficult to control the bump shape.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and has as its object to provide a bump which can be joined with a small pressing force and can be easily formed by a dry process. It is to provide an electronic circuit component.

[0008]

According to the electronic circuit component of the present invention, a bump is formed by depositing ultra-fine particles using a gas deposition method , and the bump is irradiated with light.
Thus, the hardness of the bump is changed.

[0009]

[0010]

[0011]

In the electronic circuit component of the present invention, since the bump is formed by the ultrafine particle film on which the ultrafine particles are deposited, the bump speed is controlled by controlling the collision speed, temperature and the like during the deposition of the ultrafine particles. Hardness can be adjusted. Therefore, a soft bump having low hardness can be manufactured, and the bump can be bonded to a bonding target portion such as an electrode pad with a small pressing force.

Moreover, since the ultrafine particles have a high light absorbing ability,
The properties can be changed by irradiating light, and the hardness of bumps can be adjusted by irradiating light.
Wear. Therefore, in the state of good adhesion due to the ultrafine particles
A bump is formed, and then the bump is formed by irradiating light.
The hardness of the surface layer of the pump can be adjusted.

Further, since the bump can be formed by a dry process such as a gas deposition method,
It is possible to solve the problem of the conventional bumps formed by electrochemical plating. That is, there is no possibility of polluting electronic circuit components such as IC chips (wafers) and the like, and there is no danger of emitting pollutants such as a plating solution.
The bump material such as is not excessively attached, the bump can be formed without using a mask, and the in-line production can be performed, so that mass productivity is high.

Further, according to the gas deposition method, the height and shape of the bump can be easily controlled, and a uniform bump can be formed.

[0015]

FIG. 2 is a partially cutaway front view showing an outline of an electronic circuit component 1 according to an embodiment of the present invention, and shows ultrafine particles (for example, having a particle size of about 0.1 μm or less). Has a bump 2 made of an ultrafine particle film on which is deposited.

FIG. 1 is a schematic structural view showing a bump forming apparatus 3 for forming the bump 2 of FIG. This is an apparatus for directly drawing an ultrafine particle film using a gas deposition method (published in a document of the 90th Meeting of the New Ceramics Society). It has a chamber 5, and both chambers 4, 5 are connected by a transfer pipe 6. The pressure inside the ultrafine particle generation chamber 4 and the inside of the film formation chamber 5 can be reduced by a vacuum pump 7. A gas 9 such as He gas is supplied to the ultrafine particle generation chamber 4 through a flow control valve 8.
Is supplied. The ultrafine particle generation chamber 4 is provided with an evaporation tank 10 using a resistance heating method as a heat source. The evaporation tank 10 contains Au11 as a bump material. On the other hand, a manipulator 12 for holding and moving the electronic circuit component 1 is provided in the film forming chamber 5, and a nozzle 13 protrudes from the transport pipe 6 toward the manipulator 12.

Thus, the electronic circuit component 1 is held by the manipulator 12, the pressure in the film forming chamber 5 is reduced by the vacuum pump 7, and the gas 9 is sent to the ultrafine particle generation chamber 4 while being pressurized. When heated and evaporated, the evaporated Au atoms aggregate in the air to become Au ultrafine particles, and pass through the transfer pipe 6 together with a gas 9 such as He gas due to a pressure difference between the ultrafine particle generation chamber 4 and the film formation chamber 5. Film formation chamber 5
Is sprayed from the nozzle 13 onto the surface of the electronic circuit component 1 at a high speed to form an ultrafine particle film. If the position of the nozzle 13 is adjusted to the bump formation position of the electronic circuit component 1 in this manner, the bump 2 made of an ultrafine particle film as shown in FIG. 2 can be formed on the electronic circuit component 1 without using a mask.

In this way, by depositing Au ultra-fine particles larger than Au atoms on the electronic circuit component 1 to form a bump composed of an ultra-fine particle film whose texture is coarser than that of the plating layer, the hardness is lower and softer than that of Au plating. Na bump 2
Can be manufactured. Further, even after bonding, since the hardness of the bump 2 is low and flexible, the brittleness of the bonded portion is reduced, and the bonded portion is hardly peeled off by impact or the like, and the reliability of bonding is improved. Further, by controlling the pressure difference between the ultrafine particle generation chamber 4 and the film formation chamber 5 and the temperature of the ultrafine particles, the size of the ultrafine particles, the size of the grain boundary, and the like can be changed, and the hardness of the ultrafine particle film can be changed. (Or compactness) can be adjusted. The diameter of bump 2 is nozzle 1
Since it is determined by the diameter of the bump 3, the bump 2 having a desired diameter can be obtained without using a mask. Also, bump 2
Can be controlled by the injection amount and the injection time of the ultrafine particles. Therefore, a bump of a required size can be formed at a required portion of the electronic circuit component 1 from the nozzle 13, and there is no waste of bump material. further,
Since this is a dry process, the problem of the conventional method of forming a bump by Au plating is also solved.

In the above description, A is used as the bump material.
The case where u is used has been described, but other materials such as Au, Fe, Ni, Cu, Ag, Sn, A
Most metals such as l, In, and Pt can be used.

If an alloy of a metal having the same boiling point is put in the evaporating tank, bumps can be formed from an ultrafine particle film of the alloy. Furthermore, if two or more evaporating tanks are provided in the ultrafine particle generation chamber 5 and different metal materials are put therein, even if the boiling point temperatures of both metal materials are different, a superalloy such as a binary alloy (eutectic alloy) is used. A bump made of a fine particle film can be formed. For example, according to such an alloy manufacturing method, Au
Incorporation of Co, Ag, or the like into the bumps adjusts the hardness of the bumps, improves the ohmic contact of the bumps, considers the movement of ions with the underlying film, and adds an appropriate dopant to the base metal. In this case, the bonding strength of the bump can be increased, and the bonding temperature can be lowered.

FIG. 4 is a partially cutaway front view schematically showing an electronic circuit component 21 according to another embodiment of the present invention, which has a bump 22 made of a composite composition ultrafine particle film.

FIG. 3 is a schematic structural view showing a bump forming apparatus 23 for forming the bump 22 of FIG. this is,
It has two ultrafine particle generation chambers 4a and 4b and a film formation chamber 5,
The two ultrafine particle generation chambers 4a and 4b and the film formation chamber 5 are connected by transport pipes 6a and 6b, respectively. An evaporating tank 1 using a resistance heating method as a heat source is provided in each of the ultrafine particle generation chambers 4a and 4b.
0a, 10b are provided, and each evaporating tank 10a, 10b
Different bump materials 11a and 11b are put in b. On the other hand, a manipulator 12 for holding and moving the electronic circuit component 21 is provided in the film forming chamber 5, and a nozzle is provided from each of the transport pipes 6 a and 6 b disposed adjacent to the manipulator 12 side. 13a, 13
b protrudes.

Thus, ultra-fine particles made of the first bump material 11a (for example, Au) are ejected from the nozzle 13a to the electronic circuit component 21 at a high speed to form a lower ultra-fine particle film 22a. Next, the electronic circuit component 21 is moved by the manipulator 12 so that the lower
3b, and the ultra-fine particles made of the second bump material 11b (for example, Cu) are ejected from the nozzle 13b to form the upper ultra-fine particle film 22b on the lower ultra-fine particle film 22a.
To form As a result, a bump 22 having a gradient composition (or a composite structure) as shown in FIG. 4 composed of the lower ultrafine particle film 22a and the upper ultrafine particle film 22b is obtained.

The lower and upper ultrafine particle films 22a and 22b have different performances, and different bump materials can be used in consideration of hardness, economy, adhesion, and the like. Alternatively, the same bump material may be used, and the hardness, the density, and the like may be different. More specifically, one can be an Au ultrafine particle film to have the properties required for bonding, and the other can be an AuCo ultrafine particle film to have the required hardness. Alternatively, the upper and lower ultrafine particle films 22a
And 22b, the same material can be used, the lower ultra-fine particle film 22a can have a dense structure, and the upper ultra-fine particle film 22b can have a rough and soft structure in order to improve the adhesion to the electronic circuit component 21.

In the gradient composition bump 22 shown in FIG. 4, a lower ultrafine particle film 22a and an upper ultrafine particle film 22b are laminated in a sectional manner, but gradually from the lower ultrafine particle film 22a to the upper ultrafine particle film 22b. It may be changed. To do so, the tips of the nozzles 13a and 13b may be made coincident, and the injection amount of the ultrafine particles injected from both nozzles 13a and 13b may be gradually changed. Alternatively, two evaporation tanks are provided in one ultrafine particle film generation chamber, and the composition of the bump material ejected from the nozzle is changed by gradually changing the evaporation rate of the bump material from both evaporation tanks. Is also good.

FIG. 6 is a partially cutaway front view showing an outline of an electronic circuit component 31 according to still another embodiment of the present invention. The surface portion 32a of the bump 32 formed by the ultrafine particle film is heated by laser. It is modified and has increased hardness.

FIG. 5 is a schematic configuration diagram showing a bump forming apparatus 35 for forming the bump 32 of FIG. In the bump forming apparatus 35, the nozzle 13 is
The laser light emitting end 33a of the optical fiber 33 is disposed near the optical fiber 33, and the laser light 34 emitted from a laser oscillator (not shown) is made to enter from the other end 33b of the optical fiber 33.

After the bumps 32 having a predetermined shape are formed on the electronic circuit component 31 by the ultrafine particles ejected from the nozzle 13 at a high speed, the electronic circuit component 31 is moved by the manipulator 12, and the laser beam is emitted from the laser light emitting end 33a. The surface of the bump 32 is irradiated with the emitted laser light 34. Since the diameter of the ultrafine particles and the wavelength of the laser light are of the order of magnitude close to each other, the bump 32 made of the ultrafine particle film has a high light absorbing ability, and the ultrafine particles absorb the energy of the laser light 34 and further aggregate, The grain size grows, the crystal type changes, the size of the grain boundary changes, and the physical properties such as the hardness and adhesion of the surface portion 32a of the bump 32 change. Therefore, for example, it is possible to form the ultrafine particle film 32 with good adhesion to the electronic circuit component 31, and then irradiate a laser beam to adjust the hardness of the surface portion 32a. The apparatus for irradiating the bump 32 with the laser beam 34 may be separate from the apparatus for forming the bump 32 by the gas deposition method, and the bump forming step and the laser beam irradiating step may be performed separately.

Incidentally, in each of the above bump forming apparatuses, if the ultrafine particle film 37 is formed while the electronic circuit component 36 is linearly moved by the manipulator, FIG.
As shown in (a), a linear film pattern can be drawn. If the nozzle is opened and closed by a shutter at that time, an ultrafine particle film 38 having an intermittent (or dotted) film pattern can be drawn as shown in FIG. 7B. Further, the electronic circuit component 36 is controlled by the manipulator.
By rotating, the ultrafine particle film 39 having an annular film pattern can be drawn as shown in FIG. 7C. Therefore, the bump forming apparatus can be used not only for drawing bumps but also for drawing other electrodes and wiring patterns.

Next, a specific electronic circuit component having a bump of an ultrafine particle film will be described. 8 and 9 show a TA having bumps 42a and 42b formed by an ultrafine particle film.
IC chip 41 for mounting B and film carrier tape 4
8A shows a mushroom-shaped bump 42a, and FIG. 8B shows a straight-shaped bump 42b. These bumps 42a and 42b are
The lead 44 of the film carrier tape 43 is overlaid,
By pressurizing and heating, it is joined to the lead 44 as shown in FIG. At this time, as shown in FIG. 10, the pressing force gradually increases at the beginning, and is gradually reduced after being kept at the maximum value. However, in the case of the Au bump by the conventional electrochemical plating, the solid line is shown in FIG. Although a large pressing force was required as shown in FIG.
Then, as shown by the broken line A in FIG. 10, the joining can be performed with a low pressing force. Therefore, the energy at the time of joining is reduced.

FIGS. 11 to 13 show another embodiment of the present invention, in which a transfer bump type film carrier tape 53 in which a bump 52 is formed on a lead 51 by an ultrafine particle film.
And the IC chip 54 are shown. In this embodiment, a bump 52 provided on a lead 51 of a film carrier tape 53 is overlapped on an electrode pad 55 of an IC chip 54, and FIG.
As shown in FIG. 4, after preheating the bump 52 under a low pressing force, the bump 52 is heated under a higher pressing force, and the bump 52 is bonded to the electrode pad 55 as shown in FIG. Then, after forming the lead 51, as shown in FIG.
The IC chip 54 is attached to the wiring board 56, the leads 51 are soldered to the wiring board 56, and the IC chip 54 is sealed with a sealing resin 57. Also in this method, at the time of bump bonding, Au by conventional electrochemical plating is used.
The bump requires a large pressing force as shown by a solid line c in FIG. 14, while the bump 52 made of an ultrafine particle film can be joined with a low pressing force as shown by a broken line d in FIG.

FIGS. 15 and 16 show still another embodiment of the present invention, in which a bump 6 used in a flip chip method is used.
1 is an IC chip 62 attached. This IC chip 62
Are the electrode pads 6 on the wiring board 63 as shown in FIG.
4, the bump 61 of the ultrafine particle film and the electrode pad 64 are joined by heating and pressing. Next, sealing is performed by a sealing resin 65.

FIG. 17 shows still another embodiment of the present invention, in which bumps 75 to 75 made of an ultrafine film are provided between an IC chip 71, intermediate wiring boards 72 and 73, and a wiring board 74, respectively.
77.

FIG. 18 shows still another embodiment of the present invention, in which an IC chip (Si bare chip) 81 is bonded onto an electrode pad 84 of another Si chip 82 by a bump 83 of an ultrafine particle film. 82 is bonded (Si on Si bonding) to the electrode pad 87 of the wiring board 86 by the bump 85 of the ultrafine particle film.

FIG. 19 shows still another embodiment of the present invention, in which an IC chip 92 encapsulated in an IC package 91 is placed on a lead frame 93 by an ultrafine particle bump 9.
4 are bump-bonded.

FIG. 20 shows still another embodiment of the present invention, in which a bump 103 made of an ultrafine particle film is formed on a substrate 103 of a hybrid integrated circuit 102 on which an IC chip 101 and the like are mounted.
The hybrid integrated circuit 102 is mounted on the wiring board 105 by providing the bumps 104 and bonding the bumps 104 to the electrode pads 106 of the wiring board 105.

[0037]

According to the present invention, a soft bump having low hardness can be manufactured. Therefore, the bump can be bonded to the bonding target portion such as the electrode pad with a small pressing force, and low energy bonding can be performed. In particular, even if the number of bumps of the electronic circuit component increases and the bump interval becomes narrower, it is possible to suppress an increase in the pressing force. As a result, damage to electronic circuit components such as IC chips due to cracks and the like can be prevented, and the reliability and yield of electronic circuit components can be improved.

In addition, a bump made of an ultrafine particle film can be adjusted in hardness or the like by irradiating light, and a bump having a desired hardness can be manufactured.

Also, since the bumps can be formed by a dry process, they do not contaminate electronic circuit components such as IC chips (wafers), are clean, do not emit pollutants, and have high safety. It is economical because bump materials such as Au can be adhered only to the necessary parts, it is economical, bumps can be formed without a mask, the process is simplified, and mass production is high because in-line production is possible. There is.

Further, according to the gas deposition method, the height and shape of the bump can be easily controlled, and a uniform bump can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a bump forming apparatus according to one embodiment of the present invention.

FIG. 2 is a partially cutaway front view showing an electronic circuit component on which bumps have been manufactured by the above device.

FIG. 3 is a schematic configuration diagram showing a bump forming apparatus according to another embodiment of the present invention.

FIG. 4 is a partially cutaway front view showing an electronic circuit component on which bumps have been manufactured by the above-described apparatus.

FIG. 5 is a schematic configuration diagram showing a bump forming apparatus according to still another embodiment of the present invention.

FIG. 6 is a partially cutaway front view showing an electronic circuit component on which bumps have been manufactured by the above device.

FIGS. 7A, 7B, and 7C are views showing several examples of other film patterns that can be formed by the above-described bump forming apparatuses.

8 (a) and 8 (b) are specific examples of the present invention, and are partially cutaway front views showing TAB mounting chips and leads. FIG.

FIG. 9 is a partially cutaway front view showing the IC chip mounted with TAB.

FIG. 10 is a time chart showing a change in pressure when bonding bumps by the TAB method.

FIG. 11 is a partially cutaway front view showing an inverted bump type film carrier tape and an IC chip according to another specific embodiment of the present invention.

FIG. 12 is a cross-sectional view showing an IC chip mounted by an inverted bump method.

FIG. 13 is a partially cutaway front view showing an X part in FIG. 12;

FIG. 14 is a time chart showing a change in the pressing force when the bumps are joined by the inverted bump method.

FIG. 15 is yet another specific embodiment of the present invention,
FIG. 2 is a partially broken front view showing the flip-chip type IC chip.

FIG. 16 is a front view showing an IC chip mounted by a flip chip method.

FIG. 17 is a front view showing still another specific embodiment of the present invention.

FIG. 18 is a partially broken perspective view showing still another specific embodiment of the present invention.

FIG. 19 is a partially broken perspective view showing still another specific embodiment of the present invention.

FIG. 20 is a front view showing still another specific embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic circuit component 2 Bump 3 Bump forming apparatus 4 Ultrafine particle generation room 5 Film formation room 6 Conveyance tube 41 IC chip 42a, 42b Bump 51 Lead 52 Bump 61 Bump 62 IC chip

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/60

Claims (1)

(57) [Claims] 1. A bump is formed by depositing ultrafine particles using a gas deposition method , and a light is applied to the bump.
Electronic circuit components whose bump hardness is changed by irradiating the bumps .