JP2000150544A - Mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method by which a semiconductor device which can be handled easily can be manufactured by stably producing a thin chip at a low cost. SOLUTION: The thickness of a wafer 105 stuck to a tape 107 is reduced by uniformly etching the wafer 105 by moving an etchant at a high speed in the lateral direction against the surface of the wafer 105, by rotating the wafer 105 or moving the wafer 105 forward and backward in the lateral direction in a plane at a high speed. Then a thin chip 105' obtained by dicing the thinned wafer is fixed on a substrate 102 by heating and press-contacting the chip 105' with the substrate 102 by means of a heating head 106. Therefore, the thin chip 105' can be formed stably at a low cost and can be fixed to the substrate 102 without causing cracks in the chip 105'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device suitable for forming an extremely thin semiconductor device stably and at low cost.

[0002]

2. Description of the Related Art Conventional semiconductor device assembly techniques include:
For example, "LSI Handbook" (edited by the Institute of Electronics and Communication Engineers, Ohmsha Co., Ltd., issued on November 30, 1984,
(Pages 406 to 416), etc., and these conventional semiconductor device assembling techniques deal with a semiconductor chip having a thickness of about 200 μm or more, which does not crack even when directly handled.

[0003]

As is well known, a polishing method is widely used as a means for thinning a semiconductor wafer. However, in order to process the semiconductor wafer uniformly by the polishing method, for example, with a processing accuracy of 5% or less,
It is necessary to perform the parallel placement of the wafer and the polishing apparatus with high precision and high reproducibility. To perform such extremely high parallel placement, extremely expensive equipment is required, and practical use is difficult. Was.

There is also a method of performing polishing while monitoring the thickness of a semiconductor wafer. However, if this method is performed over a wide range of thickness, the required time becomes extremely long and the productivity is reduced. Resulting in.

[0005] Further, the thickness of the semiconductor wafer is set to, for example, 0.
When polishing is performed to a very thin thickness of about 1 μm, there is a problem that devices on the surface of the semiconductor wafer are destroyed due to stress caused by polishing.

Further, if the semiconductor chip thus thinned is directly handled by the above-mentioned conventional technique, there is a problem that the semiconductor chip itself is destroyed, and a semiconductor device is formed at a high yield and at a low cost. It was difficult to do.

An object of the present invention is to solve the above-mentioned problems of the prior art and to reduce the thickness of a semiconductor chip from 0.1 to 110 μm.
It is an object of the present invention to provide a method of manufacturing a semiconductor device which can be thinned to about m and can handle such an extremely thin chip without generating a crack.

[0008]

In order to achieve the above-mentioned object, the present invention provides a method of attaching a wafer to a tape and rotating the wafer at high speed or reciprocating in a lateral direction within the surface direction of the wafer, while etching the wafer with tape. By contacting, the wafer is uniformly etched to make the film thickness extremely small,
The thinned wafer is diced and divided into a plurality of chips, and these thin chips are sequentially brought into contact with a target substrate under heating pressure to be fixed.

Since the semiconductor wafer is brought into contact with the etchant while rotating or reciprocating at a rapid speed in the in-plane direction of the semiconductor wafer, the etching is performed very uniformly, without any unevenness or distortion. An extremely thin wafer can be obtained.

The plurality of thin chips formed by dividing such an extremely thin wafer are sequentially separated from the tape as the first substrate and heated and pressed, so that the chips are extremely thin. Instead, it can be fixed on the second substrate without cracking. In particular, by using a soft tape as the first substrate, only a desired chip can be pushed upward and only this chip can be selectively heated. Therefore, it is difficult to fix the desired chip to the second substrate. Extremely easy.

Furthermore, by bonding the second substrate and the chip via a conductive adhesive, wire bonding becomes unnecessary, which is extremely effective in simplifying the process and reducing the cost.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment 1> As shown in FIG. 1, a thin semiconductor wafer 105 is placed on a tape (HA-1506, manufactured by Hitachi Chemical Co., Ltd.) 107 held by a frame 101. 105 is a dicing groove 1
04 separates into a plurality of chips 105 ′.

Each separated chip 105 ′ is pushed upward from the back surface of the tape 107 by the heating head 106, pressed against the substrate 102 on which the adhesive 103 is applied, and heated and adhered to the substrate 102. Since the adhesive 103 is an anisotropic conductive adhesive made of a composite material of an organic substance and conductive particles, an electrode (not shown) formed on the substrate 102 and an electrode (not shown) of the thin chip 105 are provided. ) Are electrically connected to each other by pressurization and heating. The tip 105 'has a thickness of 0.1 to 1 mm.
It is a very thin chip that can be bent at about 0 μm. If the thickness is smaller than 0.1 μm, this chip 10
It becomes difficult to form various semiconductor elements in 5 ′,
If it is larger than μm, there is a possibility that cracking may occur due to bending.

Further, since the tape 107 is soft, the tape 107 is pushed upward while being heated by the heating head 106, so that the thin chip 105 'on the tape 107 is also pushed up, and the tape 107 is uniformly and stably formed on the substrate 102. Glued.

FIG. 3 is a view showing the planar structure of FIG. 1, in which a tape 107 is held by a frame 101 and a wafer 105
Are separated into chips 105 ′ by dicing grooves 104. The periphery 304 of the wafer 105 is the frame 101
And is flatly adhered to the tape 107. The frame 101 is formed of stainless steel or a plastic material. The thickness of the wafer 105 is 0.1 to 110 μm
Even though the wafer 105 is extremely thin, since it is strongly adhered to the tape 107 by the adhesive, even when dicing is performed while the wafer 105 is adhered to the tape 107, the thin chips 105 ′ are separated from the tape 107. It does not peel off.

FIG. 4 shows a state after the thin chip 105 'is fixed to the substrate 102. FIG. 4A is a plan view,
FIG. 4B is a cross-sectional view. A thin chip 105 ′ is aligned and fixed on the substrate 102. The electrodes formed on the thin chip 105 ′ and the electrodes formed on the substrate 102 are connected to each other by face-down bonding. However, they may be connected to each other by wire bonding or conductive paste.

Since thin chips can be mounted easily and easily in this manner, thinning, high performance, and low cost of semiconductor devices are promoted, and new applications can be developed.

FIG. 4C shows FIGS. 4A and 4B.
FIG. 3 is an enlarged cross-sectional view schematically showing a connection portion between a thin chip 105 ′ and a substrate 102 shown in FIG. As shown in FIG. 4C, the pad 405 is located on the surface of the thin chip 105 ′.
The passivation film 408 is provided in a portion where the passivation film has been removed, and is connected to the substrate electrode 412 provided on the surface of the substrate 102 by the conductive particles 406 and is electrically connected to each other. An organic film 409 is provided between the substrate 102 and the chip 105 ', and the organic film 409 contains conductive particles 410, and the conductive particles 410 allow conduction between the two. .

On the other hand, in the conventional method, as shown in FIG. 2, a chip 202 on a tape 203 is handled by a vacuum chuck 201 and moved onto another substrate (not shown). That is, the chips 202 placed on the tape 203 are individual chips formed by dicing the wafer, and the chips 202 pushed up by the push-up pins 204 are placed on the vacuum chuck 20.
1 and are sequentially moved one by one.

An adhesive is applied to the tape 203, and the adhesiveness is reduced by ultraviolet (UV) irradiation or heating, but the adhesiveness is still slightly left. The chip 202 can be separated from the tape 203 by the push-up pin 204 that operates.

However, in the conventional method in which the chip 202 is pushed upward by the push-up pin 204, if the thickness of the chip 202 is extremely thin, from 0.1 to 110 μm, the chip 2
02 is apt to crack and productivity is reduced.

<Embodiment 2> This embodiment shows a method of thinning a wafer.

As shown in FIG. 5A, the wafer 105
Is fixed on a tape 107 affixed to the frame 101 with an adhesive, and an etchant 502 is dropped from an etchant nozzle 501 to etch the surface of the wafer 105. Although an aqueous solution of potassium hydroxide (concentration: 40%) is used as the etchant 502 in this embodiment, an etchant other than potassium hydroxide may be used.

At this time, since the wafer 105 is rotated at a high speed of not less than 1.000 revolutions per minute, as shown in FIG. Move at high speed. Therefore, the surface of the wafer 105 is uniformly etched without any step or damage,
The wafer 105 became a thin film.

Similarly, as shown in FIG. 5 (3), the etchant 502 is moved at a high speed in the lateral direction on the surface of the wafer 105 by reciprocating the wafer 105 at a high speed of 1,000 reciprocations per minute or more. As a result, the surface of the wafer 105 was uniformly etched without a step or damage, and was thinned.

<Embodiment 3> FIG. 6 is a process diagram showing another embodiment of the present invention.

As shown in FIG. 6A, after the wafer 105 is fixed on the tape 107 attached to the frame 101, the wafer 105 is thinned by the method described in the second embodiment. 6 (2), a dicing groove 104 is formed in the wafer 105 as shown in FIG. 6 (3), and the wafer 105 is
05 '.

Next, as shown in FIG.
02, the heating head 106 is pressed from below to heat and press the desired chip 105 ′, and as shown in FIG. 6 (5), the thin chip 105 ′ is placed on the substrate 102. It was transferred and fixed via the adhesive 103. The characteristics of each chip 105 ′ are measured in advance in the wafer state before the division, and the non-defective products and the defective products are clearly defined. And fixed.

In Examples 2 and 3, the same tape as that used in Example 1 was used as the tape 107, but it goes without saying that various other tapes can be used.

<Embodiment 4> FIG. 7 is a process diagram showing another embodiment of the present invention, in which a thin chip main surface is joined by face-down bonding with the substrate main surface facing each other.

First, as shown in FIG. 7A, the wafer 1 is placed on the first tape 107 attached to the first frame 101.
7 was fixed, and the wafer 105 was thinned in the same manner as in Example 2 as shown in FIG.

As shown in FIG. 7C, the wafer 105
With the surface of the tape facing down and facing the surface of the second tape 107 'affixed to the second frame 101'.

After the first tape 107 is peeled off from the wafer 105 to form a structure in which the wafer 105 is formed on the surface of the second tape 107 ', as shown in FIG. Forming a dicing groove 104 in 105;
The chips were separated into a plurality of chips 105 '.

Next, as shown in FIG.
2 and the heating head 106 is pressed from below to apply heat and pressure, and as shown in FIG. 7 (6), the thin chip 105 ′ is attached to the substrate 102 by the anisotropic conductive adhesive 709. Glued through.

According to the present embodiment, the chip 105 'is
Is transferred to the substrate 102 after being transferred to the tape 107 ′. Therefore, the front and back sides of the semiconductor chip 105 ′ are opposite to those in the first embodiment, and the upper surface of the wafer 105 initially becomes the upper surface even when it is fixed to the substrate 102. Therefore, in this embodiment, if the desired semiconductor element is formed on the surface of the wafer 105 after the wafer 105 is thinned, the semiconductor element is formed on the chip 1 formed on the surface of the substrate 102.
05 ′.

[0037]

As apparent from the above description, the following effects can be obtained by the present invention.

(1) Since the wafer is thinned by the high-speed etchant moving along the main surface of the semiconductor wafer,
A thin wafer having a uniform film thickness can be easily obtained, and there is no possibility that distortion and defects occur.

(2) Since the peeling of the thin chip from the tape and the bonding to the substrate are performed in the same process, the thin chip can be fixed on the substrate without breaking the thin chip.

(3) Since a desired chip is selectively heated and pressed and transferred onto the substrate, a thin chip can be mounted on the substrate extremely easily and at low cost.

(4) Each chip can be connected to the substrate without wire bonding by being fixed to the substrate with an anisotropic conductive adhesive.

(5) Since the thickness of the chip is extremely thin, from 0.1 to 110 μm, which enables bending, a thin semiconductor device which is strong against bending can be realized.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention;

FIG. 2 is a diagram for explaining a conventional method.

FIG. 3 is a plan view for explaining an embodiment of the present invention;

FIG. 4 is a diagram for explaining the present invention;

FIG. 5 is a diagram for explaining thinning of a wafer according to the present invention;

FIG. 6 is a process chart showing another embodiment of the present invention;

FIG. 7 is a process chart showing another embodiment of the present invention.

[Explanation of symbols]

101 ... frame, 101 '... second frame, 102 ... substrate,
103: adhesive, 104: dicing groove, 105:
Wafer, 105 ': chip, 106: heating head,
107 ... tape, 107 '... second tape, 201 ...
Vacuum chuck, 202: chip, 203: tape,
204: push-up pin, 304: around the wafer, 4
05: pad, 406: conductive particles between electrodes, 408: passivation film, 409: organic film, 410:
Conductive particles, 412: substrate electrode, 501: etch liquid nozzle, 502: etch liquid.

Claims (7)

[Claims] A step of preparing a plurality of IC chips which are completely separated by dicing and are attached to a dicing tape in an arrangement in a wafer state; Having a step of facing one of the IC chips in a standing state and a step of fixing the substrate and the IC chip by selectively heating and pressing the IC chip facing the substrate. A mounting method characterized by the following. 2. The fixing of the substrate and the IC chip,
2. The mounting method according to claim 1, wherein the mounting is performed using an adhesive. 3. The mounting method according to claim 2, wherein the adhesive is an anisotropic conductive adhesive. 4. A step of preparing a plurality of IC chips which are completely separated and adhered to a tape in an arrangement in a state of a wafer, and wherein a substrate on which wiring is formed and the IC chip is adhered to said tape. And a step of extruding the IC chip facing the substrate with a heating head and pressing the IC chip against the substrate. 5. The mounting method according to claim 4, wherein the heating head has a flat surface. 6. A step of preparing a plurality of IC chips which are completely separated by dicing, adhered to a dicing tape in an arrangement in a wafer state, and have a thickness in a range of 0.1 μm to 110 μm; A step of causing the formed substrate to face one of the IC chips that are still attached to the dicing tape; and selectively heating and pressing the IC chip facing the substrate to form a contact with the substrate. Fixing the IC chip. 7. A wafer which is completely separated and affixed to a tape in an as-wafer arrangement, and has a thickness of 0.1 μm to 110 μm.
Preparing a plurality of IC chips in the range of: a step of making the substrate on which the wiring is formed face one of the IC chips which is still attached to the tape; Extruding the IC chip with a heating head and pressing the IC chip against the substrate.