JP6966281B2 - Transfer substrate and transfer method - Google Patents

Description

The present invention relates to a transfer substrate and a transfer method for transferring a semiconductor chip with high accuracy.

Semiconductor chips are becoming smaller in order to reduce costs, and efforts are being made to mount them at high speed and with high accuracy. In particular, LEDs used in displays are required to mount LED chips of 50 μm × 50 μm or less, which are called micro LEDs, with an accuracy of several μm at high speed.

In Patent Document 1, an LED chip formed in a grid pattern on a wafer is irradiated with a band-shaped laser beam to be collectively transferred to the transfer substrate 200 for each line or a plurality of lines, and then transferred to the transfer substrate 200. A configuration is described in which a plurality of later LED chips are irradiated with a band-shaped laser beam to collectively transfer one line or each of the plurality of lines to the transfer substrate 300.

Patent Document 1: Japanese Unexamined Patent Publication No. 2010-161221

However, the one described in Patent Document 1 has a problem that the LED chip collides with the transfer substrate during transfer, causing crushing and misalignment.

An object of the present invention is to solve the above problems, to alleviate the impact at the time of transfer, and to transfer the semiconductor chip with high accuracy.

In order to solve the above problems, the present invention transfers a semiconductor chip from a transfer source substrate arranged with a gap by irradiation with a laser beam, and at the same time , holds the semiconductor chip and transfers the semiconductor chip to the transfer destination substrate. Transfer substrate
A base material having a first main surface and a second main surface,
At least a shock absorbing layer for cushioning a shock at the time of transfer of a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the base material, is provided .
Provided is a transfer substrate characterized in that the leave hardness of the shock absorbing layer is 50 or more and 90 or less when the leave hardness of the base material is 100.

With this configuration, the impact at the time of transfer can be alleviated and the semiconductor chip can be transferred with high accuracy.

The chip fixing layer for holding the semiconductor chip may be provided with the second main surface in contact with the first main surface of the shock absorbing layer.

With this configuration, the semiconductor chip can be reliably held by the chip fixing layer even in the impact absorbing layer having poor adhesiveness.

Further, in order to solve the above problems, the present invention is a transfer method for transferring a semiconductor chip.
The first base material having the first main surface and the second main surface and the first main surface of the first base material are provided in contact with the second main surface to alleviate the impact at the time of transfer of the semiconductor chip. A first transfer substrate preparation step for preparing a first transfer substrate provided with at least a first shock absorbing layer for
A second base material having a first main surface and a second main surface and a second main surface in contact with the first main surface of the second base material are provided to reduce the impact during transfer of a semiconductor chip. A second transfer substrate preparation step for preparing a second transfer substrate provided with at least a second shock absorbing layer for
A semiconductor chip holding step of holding the semiconductor chip on the first main surface of the first shock absorbing layer in the first transfer substrate, and
A transfer in which the first main surface of the first shock absorbing layer in the first transfer substrate and the first main surface of the second shock absorbing layer in the second transfer substrate are arranged so as to face each other with a gap. Board placement process and
The semiconductor chip is separated from the first main surface of the first shock absorbing layer by irradiating a laser beam from the second main surface side of the first base material in the first transfer substrate, and the second transfer substrate is said to have the same. The present invention provides a transfer method comprising a transfer step of moving the second shock absorbing layer to the first main surface and transferring the transfer.

With this configuration, the impact at the time of transfer can be alleviated and the semiconductor chip can be transferred with high accuracy.

Further, in order to solve the above problems, the present invention is a transfer method for transferring a semiconductor chip.
The first base material having the first main surface and the second main surface and the first main surface of the first base material are provided in contact with the second main surface to alleviate the impact at the time of transfer of the semiconductor chip. A first shock absorbing layer for holding a semiconductor chip, and a first chip fixing layer for holding a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the first shock absorbing layer. The first transfer substrate preparation process for preparing the transfer substrate, and
A second base material having a first main surface and a second main surface and a second main surface in contact with the first main surface of the second base material are provided to reduce the impact during transfer of a semiconductor chip. A second shock absorbing layer for holding a semiconductor chip, and a second chip fixing layer for holding a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the second shock absorbing layer. The second transfer substrate preparation process for preparing the transfer substrate, and
A semiconductor chip holding step of holding a semiconductor chip on the first main surface of the first chip fixing layer in the first transfer substrate, and
A transfer in which the first main surface of the first chip fixing layer on the first transfer substrate and the first main surface of the second chip fixing layer on the second transfer substrate are arranged so as to face each other with a gap. Board placement process and
A laser beam is irradiated from the second main surface side of the first base material on the first transfer substrate to separate the semiconductor chip and move to the first main surface of the second chip fixing layer of the second transfer substrate. It provides a transfer method characterized by comprising a transfer step of causing and transferring.

With this configuration, the impact at the time of transfer can be alleviated and the semiconductor chip can be transferred with high accuracy.

According to the transfer substrate and the transfer method of the present invention, the impact at the time of transfer can be alleviated and the semiconductor chip can be transferred with high accuracy.

It is a figure explaining the cross section of the transfer substrate in Example 1 of this invention. It is a figure explaining the semiconductor chip holding process in Example 1 of this invention, (a) is a plan view, (b) is a side sectional view. It is a figure explaining the transfer process in Example 1 of this invention. It is a figure explaining the cross section of the transfer substrate in Example 2 of this invention. It is a figure explaining the semiconductor chip holding process in Example 2 of this invention, (a) is a plan view, (b) is a side sectional view. It is a figure explaining the transfer process in Example 2 of this invention.

Example 1 of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram illustrating a cross section of a transfer substrate according to a first embodiment of the present invention. 2A and 2B are views for explaining the semiconductor chip holding process according to the first embodiment of the present invention, in which FIG. 2A is a plan view and FIG. 2B is a side sectional view. FIG. 3 is a diagram illustrating a transfer process according to the first embodiment of the present invention.

(Transfer Substrate) The transfer substrate in the present invention is for transferring a semiconductor chip from a transfer source substrate by irradiation with a laser beam, holding the semiconductor chip, and transferring the semiconductor chip to a transfer destination substrate, and the transfer is repeated. Can be used for.

As shown in FIG. 1, the transfer substrate 10 in the first embodiment is provided with a shock absorbing layer 2 in which the second main surface 2b is in contact with the first main surface 1a of the base material 1. The base material 1 is made of glass, is made of a substantially quadrangle in a plan view, and has a thickness of 0.7 mm. Further, the shock absorbing layer 2 is made of a silicone resin, spreads over the entire base material 1 in a plan view, and has a thickness of about 20 μm. By providing the shock absorbing layer 2, the impact when the semiconductor chip S is urged from the transfer source substrate to the transfer substrate 10 by laser light irradiation and transferred is mitigated, and the semiconductor chip S is crushed and positioned. It is possible to prevent the deviation.

That is, the semiconductor chip S such as a micro LED formed on the carrier substrate 50 made of sapphire irradiates the laser beam L from the back surface of the sapphire substrate and is a part of the GaN layer at the interface between the carrier substrate 50 and the semiconductor chip S. Is decomposed into Ga and N2 (nitrogen) to separate the semiconductor chip S (see FIG. 2).

Here, in order to decompose GaN into Ga and nitrogen, the laser light needs to have a wavelength absorbed by GaN. That is, the laser beam L that emits a wavelength shorter than 365 nm, which corresponds to the energy gap of 3.4 eV of GaN, is irradiated. However, this wavelength corresponds to GaN, and some of the actual LEDs are doped with In or Al, or the principal component is different from GaN, and their energy gaps are different from GaN. Therefore, it is necessary to select the wavelength of the laser beam L according to the energy gap of the material of the semiconductor chip S.

A method of irradiating the laser beam L to decompose a part of the GaN layer at the interface between the carrier substrate 50 and the semiconductor chip S into Ga and N to separate the semiconductor chip S is called laser lift-off. At the time of this separation, since a gas composed of nitrogen is generated, a vigorous momentum is applied toward the transfer substrate 10 at the transfer destination. The violently vigorous semiconductor chip S may be crushed or the transfer position may be displaced by colliding with the transfer substrate. Therefore, as described above, the transfer substrate 10 is provided with the shock absorbing layer 2.

In Example 1, the shock absorbing layer 2 is made of a silicone resin, but the present invention is not limited to this, and can be changed as appropriate for convenience. For example, it may be made of an acrylic resin or a silicone foam, and at least the laser beam L may be transmitted and cushioning property may be provided.

The cushioning property of the shock absorbing layer 2 is expressed by the leave hardness of the repulsive hardness tester, and when the leave hardness of the base material 1 is 100, the leave hardness of the shock absorbing layer 2 formed on the base material 1 is 50 to 50 to 90 is preferable. If it is less than 50, the impact absorbing layer 2 may be elastically deformed during transfer and it may take time to recover the shape of the impact absorbing layer 2, so that it is not preferable. If it exceeds 90, the impact absorbing property is weak and the semiconductor chip S may be crushed. It is not suitable because there is. The leave hardness referred to here was evaluated using a repulsive portable hardness meter (HH-411 manufactured by Mitutoyo). The base material 1 on which the shock absorbing layer 2 was formed was placed on the stone surface plate, and the detector was installed so as to be perpendicular to the two surfaces of the shock absorbing layer for measurement. It was measured 3 times per sample and the average value was expressed as the leave hardness. Further, the transparency of the laser beam L of the shock absorbing layer 2 may be 40% or more. If the transparency of the laser light L is less than 40%, it is unsuitable because the laser light L may be absorbed and the first shock absorbing layer may be deteriorated.

Further, when the adhesiveness of the shock absorbing layer is poor, it is desirable to laminate a chip fixing layer having adhesiveness for holding the semiconductor chip S as described later, but this is not always essential and is static. The semiconductor chip S may be held by means of electric adsorption. That is, the transfer substrate 10 may be provided with at least a shock absorbing layer 2.

Further, in the first embodiment, the base material 1 is made of glass, but the present invention is not necessarily limited to this, and it can be changed as appropriate for convenience. For example, it may be composed of sapphire or a resin film, and at least laser light may be transmitted.

Further, in Example 1, the thickness of the base material 1 is set to 0.7 mm, and the thickness of the shock absorbing layer 2 is set to 20 μm, but the thickness is not necessarily limited to this and can be changed as appropriate. For example, the thickness of the base material 1 may be 0.8 mm or more, or 0.6 mm or less. The thickness of the shock absorbing layer 2 may be about 5 to 300 μm. That is, if the thickness is less than 5 μm, the impact of the semiconductor chip cannot be completely absorbed and the semiconductor chip S may be crushed, which is unsuitable. Since the absorption layer has light absorption, it is unsuitable because it may absorb laser light and deteriorate the shock absorption layer so that it cannot be transferred.

(Transfer Method) First, the first transfer substrate preparation step is executed, and the first base material 1 having the first main surface 1a and the second main surface 1b and the first main surface 1a of the first base material are subjected to the first step. The first transfer substrate 10 provided with the first shock absorbing layer 2 provided in contact with the two main surfaces 2b is prepared. Similarly, the second transfer substrate preparation step is executed on the second base material 101 having the first main surface 101a and the second main surface 101b and the first main surface 101a of the second base material 101. A second transfer substrate 110 including a second shock absorbing layer 102 provided in contact with the second main surface 102b is prepared.

The plane size of the first transfer substrate 10 and the second transfer substrate 110 may be large enough to hold a required number of semiconductor chips S, and may be made of glass having a thickness of about 0.7 mm. Further, the first shock absorbing layer 2 and the second shock absorbing layer 102 may be made of a silicone resin and may have a thickness of 20 μm or more. The silicone resin has shock absorption and adhesiveness, and can absorb the shock of the semiconductor chip at the time of transfer and can hold it reliably.

The adhesiveness of the first impact absorbing layer 2 and the second impact absorbing layer 102 is expressed by an adhesive force, and the adhesive force is preferably about 0.05 to 5 mN. That is, if the adhesive strength is less than 0.05 mN, the adhesive strength is weak and the semiconductor chip S may be displaced due to an impact during transfer, which is not suitable. Further, if it is thicker than 5 mN, when the laser lift-off to the second transfer substrate is performed after holding the semiconductor chip, the adhesive force is too strong and it may not be completely peeled off, which is not preferable. The adhesive strength here is the indenter diameter φ20 um, maximum applied load 10 mN, maximum applied load arrival time 5 seconds, maximum applied load holding using a thin film mechanical property evaluation device (iNano type nano indenter system manufactured by Nanomechanics, USA). Evaluated in 2 seconds. It was measured 10 times for each sample, and the average value was displayed as the adhesive strength.

Next, the semiconductor chip holding step is executed to hold the semiconductor chip S on the first main surface 2a of the first shock absorbing layer 2 in the first transfer substrate 10. That is, as shown in FIG. 2, the surface of the carrier substrate 50 made of sapphire on which a plurality of semiconductor chips S are formed and the first main surface 2a of the first shock absorbing layer 2 of the first transfer substrate 10 are opposed to each other and carriers are used. By moving the laser beam L while irradiating it in a line from the back side of the substrate 50, all the semiconductor chips S held by the carrier substrate 50 are moved on the first main surface of the first shock absorbing layer 2 on the first transfer substrate 10. 2a holds the semiconductor chip S.

That is, a part of the GaN layer in the carrier substrate 50 made of sapphire is decomposed into Ga and nitrogen by laser light L irradiation, and the semiconductor chip S is separated and urged toward the first transfer substrate 10. This method is called laser lift-off, and the separated semiconductor chip S is urged by the generation of a gas composed of nitrogen when GaN is decomposed and transferred to the first transfer substrate 10.

By the way, as described above, in the decomposition of GaN, the wavelength needs to be shorter than 365 nm. Therefore, an excimer laser that emits ultraviolet light is usually used as a laser light source, but in Example 1, a YAG laser that is easy to handle is used. However, since the transmission wavelength of the YAG laser is 1064 nm, which is a long wavelength in the infrared region, the third harmonic (wavelength 355 nm) or the fourth harmonic (wavelength 266 nm) is used as the laser light L in combination with the nonlinear optical crystal. ing. As the light source of the laser light L, another type of laser light source such as a semiconductor laser may be used as long as the conditions such as wavelength and irradiation energy are satisfied.

Since the first impact absorbing layer 2 is provided at the time of laser lift-off, even if the semiconductor chip S is violently urged, the impact of collision is alleviated, and crushing and misalignment can be prevented.

Further, by irradiating the carrier substrate 50 and the first transfer substrate 10 with a line-shaped laser beam while moving them in the same direction or in the opposite directions and adjusting the moving speeds of the respective lines, the semiconductor chip S can be arbitrarily moved for each line. It can be transferred at a pitch.

Next, the transfer substrate arranging step is executed to execute the first main surface 2a of the first shock absorbing layer 2 in the first transfer substrate 10 and the first main surface 102a of the second shock absorbing layer 102 in the second transfer substrate 110. And are arranged so as to face each other. At this time, the distance between the gaps between the first transfer substrate 20 and the second transfer substrate 110 facing each other is about 50 μm, but the distance is not necessarily limited to this and can be changed as appropriate. For example, it may be about 10 to 200 μm. If the gap is less than 10 μm, both substrates may come into contact with each other due to variations in surface roughness between the first transfer substrate 10 and the second transfer substrate 110, which may require a step of peeling off the contacted substrates, which is not suitable. .. Further, if it is larger than 200 μm, the moving distance of the semiconductor chip S that moves from the first transfer substrate 10 to the second transfer substrate 110 in the transfer step described later becomes long, the transfer accuracy is lowered, and the position shift of the semiconductor chip S is deviated. It is not preferable because it may occur.

Next, the transfer step is executed to transfer the semiconductor chip S to the second transfer substrate 110. That is, the laser beam L is irradiated from the second main surface 1b side of the first base material 1 on the first transfer substrate 10. At this time, in the first embodiment, the first base material 1 made of glass and the first shock absorbing layer 2 made of silicone resin have the transparency of the laser beam L. Therefore, the laser beam L irradiated from the second main surface 1b side of the first base material 1 on the first transfer substrate 10 is a gas at the interface between the first main surface 2a of the first shock absorbing layer 2 and the semiconductor chip S. Is generated and the semiconductor chip S is separated. Then, the semiconductor chip S is urged and transferred toward the first main surface 102a of the second shock absorbing layer 102 of the second transfer substrate 110 by the gas generated at that time.

In this transfer step, the first transfer is performed by irradiating the laser beam while keeping the first transfer substrate 10 and the second transfer substrate 110 facing each other and moving them in the same direction or in opposite directions while adjusting the speeds of each other. It can be transferred and held on the second transfer substrate 110 at a pitch different from the pitch of the semiconductor chip S held on the substrate 10. As a result, for example, when the semiconductor chip S is a micro LED, it can be rearranged at a pitch required for the display.

After the transfer step, the semiconductor chip S held on the second transfer board 110 can be transferred to another substrate such as a circuit board by the same transfer method.

Here, as described above, in the semiconductor chip holding step, the transfer substrate 10 functions as a transfer destination substrate on which the semiconductor chip S is transferred. Further, in the transfer step, the transfer substrate 10 functions as a transfer source substrate for transferring the held semiconductor chip S. As described above, the transfer substrate in the present invention also functions as a transfer destination substrate and also as a transfer source substrate, and can be repeatedly used for transfer.

In Example 1, in the transfer substrate arranging step and the transfer step, as shown in FIG. 3, the first transfer substrate 10 of the transfer source is arranged on the upper side, and the second transfer substrate 110 of the transfer destination is arranged on the lower side. However, it is not necessarily limited to this and can be changed as appropriate. For example, the transfer source first transfer substrate 10 may be arranged on the lower side and the transfer destination second transfer substrate 110 may be arranged on the upper side, or both transfer substrates may be arranged in the vertical direction and the semiconductor chip S may be arranged. May be configured to be transferred horizontally.

As described above, in the first embodiment, the semiconductor chip is transferred from the transfer source substrate by irradiation with laser light, and the semiconductor chip is held and transferred to the transfer destination substrate. A base material having a surface and a second main surface, a shock absorbing layer provided with the first main surface of the base material in contact with the second main surface, and a shock absorbing layer for alleviating the impact during transfer of the semiconductor chip. The semiconductor chip can be transferred with high accuracy by alleviating the impact at the time of transfer by the transfer substrate having at least the above.

Further, it is a transfer method for transferring a semiconductor chip, in which a first base material having a first main surface and a second main surface and a second main surface are in contact with the first main surface of the first base material. A first transfer substrate preparation step for preparing a first transfer substrate provided with at least a first impact absorbing layer for alleviating an impact during transfer of a semiconductor chip, and a first main surface and a second main surface. A second base material having a A second transfer substrate preparation step of preparing a second transfer substrate provided with at least, a semiconductor chip holding step of holding the semiconductor chip on the first main surface of the first shock absorbing layer in the first transfer substrate, and the first. A transfer substrate arranging step of arranging the first main surface of the first shock absorbing layer in one transfer substrate and the first main surface of the second shock absorbing layer in the second transfer substrate so as to face each other, and the first. The semiconductor chip is separated from the first main surface of the first shock absorbing layer by irradiating laser light from the second main surface side of the first base material in one transfer substrate, and the second transfer substrate is said. 2. The semiconductor chip can be transferred with high accuracy by alleviating the impact at the time of transfer by the transfer method including the transfer step of transferring to the first main surface of the shock absorbing layer.

Example 2 of the present invention is different from Example 1 in that a chip fixing layer having further adhesiveness is laminated on the surface of the shock absorbing layer in the transfer substrate.

Example 2 of the present invention will be described with reference to FIGS. 4 to 6. FIG. 4 is a diagram illustrating a cross section of the transfer substrate according to the second embodiment of the present invention. 5A and 5B are views for explaining the semiconductor chip holding process according to the second embodiment of the present invention, in which FIG. 5A is a plan view and FIG. 5B is a side sectional view. FIG. 6 is a diagram illustrating a transfer process according to a second embodiment of the present invention.

(Transfer Substrate) As shown in FIG. 4, the transfer substrate 20 in Example 2 is provided with a shock absorbing layer 2 in contact with the first main surface 1a of the base material 1 in contact with the second main surface 2b, and further shock absorbing. A chip fixing layer 3 made of polyimide is provided with the second main surface 3b in contact with the first main surface 2a of the layer 2. In Example 2, the shock absorbing layer 2 is made of a silicone foam. The silicone foam contains air bubbles inside and has excellent shock absorption.

When the shock absorbing layer 2 is made of a silicone resin or an acrylic resin, these materials have adhesiveness, so that the semiconductor chip S can be held. However, the silicone foam has poor adhesiveness, and it is difficult to hold the semiconductor chip S as it is. Therefore, in the second embodiment, the adhesive chip fixing layer 3 is laminated on the first main surface 2a side of the shock absorbing layer 2 to have adhesiveness. Specifically, the chip fixing layer 3 is made of polyimide having a thickness of 10 μm over the entire area of the transfer substrate 20 in a plan view.

In this way, the semiconductor chip S is transferred from the transfer source substrate to the transfer substrate 20 by providing the chip fixing layer 3 made of polyimide in contact with the first main surface 2a of the shock absorbing layer 2 with the second main surface 3b in contact with the first main surface 2a. The impact at the time can be alleviated to prevent the semiconductor chip S from being crushed or misaligned, and the semiconductor chip S can be reliably held.

In Example 2, the chip fixing layer 3 is made of polyimide having a thickness of 10 μm, but the present invention is not limited to this and can be changed as appropriate. For example, the thickness may be about 3 to 50 μm. That is, if the thickness is less than 3 μm, sufficient adhesiveness may not be exhibited and chip misalignment may occur, which is not suitable. Further, if it is thicker than 50 μm, the physical characteristics of the chip fixing layer dominate the surface physical properties of the transfer substrate, which may impair the shock absorption of the shock absorbing layer, which is not preferable. Further, it may be composed of a material having adhesiveness other than polyimide.

Further, in the second embodiment, the shock absorbing layer is formed of the silicone foam, but the present invention is not necessarily limited to this and can be appropriately changed. For example, the shock absorbing layer may be formed of a silicone resin or an acrylic resin, and the chip fixing layer may be laminated on the surface thereof.

(Transfer Method) First, the first transfer substrate preparation step is executed, and the first base material 1 having the first main surface 1a and the second main surface 1b and the first main surface 1a of the first base material 1 are formed. The first shock absorbing layer 2 provided in contact with the second main surface 2b and the first chip fixing layer 3 provided in contact with the first main surface 2a of the first shock absorbing layer 2 with the second main surface 3b. The prepared first transfer substrate 20 is prepared. Similarly, the second transfer substrate preparation step is executed on the second base material 101 having the first main surface 101a and the second main surface 101b and the first main surface 101a of the second base material 101. A second shock absorbing layer 102 provided in contact with the second main surface 102b and a second chip fixing layer 103 provided in contact with the first main surface 102a of the second shock absorbing layer 102 with the second main surface 103b. The provided second transfer substrate 120 is prepared.

In Example 2, the first base material 1 and the second base material 101 are glass, the first shock absorbing layer 2 and the second shock absorbing layer 102 are silicone resins, and the first chip fixing layer 3 and the second chip fixing layer 103 are polyimides. It is composed of. With this configuration, the impact of the semiconductor chip S at the time of transfer can be alleviated by the silicone resin, and the semiconductor chip S can be reliably held by laminating the polyimide on the silicone resin having poor adhesiveness.

Next, the semiconductor chip holding step is executed to hold the semiconductor chip S on the first main surface 3a of the first chip fixing layer 3 in the first transfer substrate 20. That is, as shown in FIG. 5, the surface of the carrier substrate 50 made of sapphire on which the semiconductor chip S is formed on which the semiconductor chip S is formed and the first main surface 3a of the first chip fixing layer 3 on the first transfer substrate 20 are formed. All the semiconductor chips S held in the carrier substrate 50 are fixed to the first chip in the first transfer substrate 20 by arranging them facing each other and moving them while irradiating the laser beam L from the back side of the carrier substrate 50 in a line shape. The semiconductor chip S is transferred and held on the first main surface 3a of the layer 3.

That is, by irradiating the laser beam, a part of the GaN layer in the carrier substrate 50 made of sapphire is decomposed into Ga and nitrogen, and the semiconductor chip S is separated and urged toward the first transfer substrate 20. This method is called laser lift-off, and the separated semiconductor chip S is urged by the generation of a gas made of nitrogen when GaN is decomposed and transferred to the first transfer substrate 20.

At this time, since the second main surface 2b is in contact with the first main surface 1a of the first transfer substrate 10 and the first shock absorbing layer 2 is provided, even if the semiconductor chip S is violently urged, the impact of collision is generated. It is relaxed and can prevent crushing and misalignment. Further, since the chip fixing layer 3 is provided with the second main surface 3b in contact with the first main surface 2a of the first shock absorbing layer 2, the transferred semiconductor chip S can be reliably held.

Next, the transfer substrate arranging step is executed to execute the first main surface 3a of the first chip fixing layer 3 in the first transfer substrate 20 and the first main surface 103a of the second chip fixing layer 103 in the second transfer substrate 120. And are arranged so as to face each other. At this time, the distance between the gaps between the first transfer substrate 20 and the second transfer substrate 120 facing each other is about 50 μm, but it is not necessarily the same. For example, it may be about 10 to 200 μm. That is, if the thickness is less than 10 μm, both substrates may come into contact with each other due to variations in the surface roughness of the first transfer substrate 20 and the second transfer substrate 120, and a step of peeling off the contacted substrates may be required, which is not suitable. be. Further, if it is thicker than 200 μm, the transfer accuracy is lowered during the transfer step described later, and the position of the semiconductor chip S may be displaced, which is not preferable.

Next, a transfer step is executed to transfer the semiconductor chip S to the second transfer substrate 120. That is, the laser beam L is irradiated from the second main surface 1b side of the first base material 1 on the first transfer substrate 20. At this time, in the second embodiment, the first base material 1 made of glass and the first shock absorbing layer 2 made of silicone resin are transparent to the laser beam L, but the first chip fixing layer made of polyimide is used. 3 has no transparency. Therefore, the laser beam L irradiated from the second main surface 1b side of the first base material 1 in the first transfer substrate 20 is absorbed by the first chip fixing layer 3 made of polyimide and burned out, so that the first shock absorbing layer The first main surface 2a of 2 and the semiconductor chip S are separated from each other. Then, the semiconductor chip S is urged and transferred toward the first main surface 103a of the second chip fixing layer 103 of the second transfer substrate 120 by the gas generated at that time.

The laser beam L that burns the first chip fixing layer 3 needs to have a wavelength that is absorbed by the first chip fixing layer 3, and a laser light source having a wavelength corresponding to the material of the first chip fixing layer 3 is selected. There is a need to. Further, the transmission of the laser beam L of the first chip fixing layer 3 is preferably 60% or less. If the transparency of the laser beam L is greater than 60%, it is unsuitable because the energy absorption of the laser beam L is insufficient and there is a risk that the laser beam L will not be burnt and transferred.

In the transfer step, the first transfer substrate 20 and the second transfer substrate 120 are kept facing each other, and the first transfer substrate is irradiated with laser light while adjusting the speeds of the first transfer substrate 20 and the second transfer substrate 120 in the same direction or opposite directions. The pitch of the semiconductor chip S held in 20 can be transferred and held on the second transfer substrate 120 at different pitches. As a result, for example, when the semiconductor chip S is a micro LED, it can be rearranged at a pitch required for the display.

After the transfer step, the semiconductor chip S held on the second transfer board 120 can be transferred to another substrate such as a circuit board by the same transfer method. When mounted on a circuit board, it often goes through a heating process. In that case, since the chip fixing layer made of polyimide has heat resistance, it can withstand the heating process at the time of mounting.

In Example 2, in the transfer substrate arranging step and the transfer step, as shown in FIG. 6, the first transfer substrate 20 of the transfer source is arranged on the upper side, and the second transfer substrate 120 of the transfer destination is arranged on the lower side. However, it is not necessarily limited to this and can be changed as appropriate. For example, the transfer source first transfer substrate 20 may be arranged on the lower side and the transfer destination second transfer substrate 120 may be arranged on the upper side, or both substrates may be arranged in the vertical direction to form the semiconductor chip S. It may be configured to transfer in the horizontal direction.

As described above, in the second embodiment, the chip fixing layer for holding the semiconductor chip is provided with the second main surface in contact with the first main surface of the shock absorbing layer, so that the shock absorbing layer has poor adhesiveness. The semiconductor chip can be reliably held by the chip fixing layer.

Further, it is a transfer method for transferring a semiconductor chip, in which a first base material having a first main surface and a second main surface and a second main surface are in contact with the first main surface of the first base material. To hold a semiconductor chip provided with a first shock absorbing layer for alleviating an impact during transfer of the semiconductor chip and a second main surface in contact with the first main surface of the first shock absorbing layer. A first transfer substrate preparation step for preparing a first transfer substrate including the first chip fixing layer, a second substrate having a first main surface and a second main surface, and the second substrate. A second shock absorbing layer for reducing the impact at the time of transfer of the semiconductor chip, which is provided in contact with the first main surface of the semiconductor chip, and a second main surface on the first main surface of the second shock absorbing layer. A second transfer substrate preparation step of preparing a second transfer substrate including a second chip fixing layer for holding a semiconductor chip, which is provided in contact with the surfaces, and fixing of the first chip on the first transfer substrate. The semiconductor chip holding step of holding the semiconductor chip on the first main surface of the layer, the first main surface of the first chip fixing layer on the first transfer substrate, and the second chip fixing layer on the second transfer substrate. The semiconductor chip is separated by irradiating a transfer substrate arranging step of arranging the first main surface so as to face the first main surface and irradiating a laser beam from the second main surface side of the first base material in the first transfer substrate. By a transfer method characterized by including a transfer step of transferring to the first main surface of the second chip fixing layer of the second transfer substrate, the impact at the time of transfer is alleviated and the semiconductor chip is made highly accurate. In addition to being able to transfer, the semiconductor chip can be reliably held by the chip fixing layer even in a shock absorbing layer having poor adhesiveness.

Example 3 of the present invention is different from Example 1 and Example 2 in that the configuration of the transfer source substrate and the configuration of the transfer destination substrate are different.

That is, in the transfer method in Example 3, the semiconductor chip S is separated by irradiating the back surface of the first transfer substrate 20 provided with the first chip fixing layer 3 made of the above-mentioned polyimide with laser light L to separate the semiconductor chip S, and silicone resin or acrylic. It is transferred to a second transfer substrate 110 having a second shock absorbing layer 102 made of a based resin and not having a chip fixing layer.

In this case as well, the first transfer substrate 20 can reliably hold the semiconductor chip S, and the second transfer substrate 110 can reliably hold the semiconductor chip S while being able to alleviate the impact during transfer. be able to.

(Modified Example) The transfer method in the modified example is to irradiate laser light L from the back surface of the first transfer substrate 10 having the first impact absorbing layer 2 made of the above-mentioned silicone resin or acrylic resin and not having the chip fixing layer. The semiconductor chip S is separated and transferred to a second transfer substrate 120 provided with a second chip fixing layer 103 made of polyimide.

In this case as well, the first transfer substrate 10 can reliably hold the semiconductor chip S, and the second transfer substrate 120 can reliably hold the semiconductor chip S while being able to alleviate the impact during transfer. be able to.

As described above, in Example 3, a transfer substrate having a shock absorbing layer made of a silicone resin or an acrylic resin and not having a chip fixing layer, and a transfer substrate having a shock absorbing layer and a chip fixing layer made of polyimide are used. In the meantime, the impact at the time of transfer can be alleviated and the semiconductor chip can be reliably held.

The transfer substrate and transfer method in the present invention can be widely used in the field of transferring a semiconductor chip.

1: Base material (first base material) 2: Shock absorbing layer (first shock absorbing layer) 3: Chip fixing layer (first chip fixing layer) 1a: First main surface 1b: Second main surface 2a: First Main surface 2b: Second main surface 3a: First main surface 3b: Second main surface 10: Transfer substrate (first transfer substrate) 20: Transfer substrate (first transfer substrate) 50: Carrier substrate 101: Second substrate 102: Second shock absorbing layer 103: Second chip fixing layer 101a: First main surface 101b: Second main surface 102a: First main surface 102b: Second main surface 103a: First main surface 103b: Second main surface 110: Second transfer substrate 120: Second transfer substrate L: Laser light S: Semiconductor chip

Claims (4)

A transfer substrate for transferring a semiconductor chip from a transfer source substrate arranged with a gap by irradiation with laser light, and for holding the semiconductor chip and transferring the semiconductor chip to the transfer destination substrate.
A base material having a first main surface and a second main surface,
At least a shock absorbing layer for cushioning a shock at the time of transfer of a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the base material, is provided.
A transfer substrate characterized in that the leave hardness of the shock absorbing layer is 50 or more and 90 or less when the leave hardness of the base material is 100. The transfer substrate according to claim 1, wherein a chip fixing layer for holding a semiconductor chip is provided in contact with a first main surface of the shock absorbing layer with a second main surface. A transfer method for transferring semiconductor chips,
The first base material having the first main surface and the second main surface and the first main surface of the first base material are provided in contact with the second main surface to alleviate the impact at the time of transfer of the semiconductor chip. A first transfer substrate preparation step for preparing a first transfer substrate provided with at least a first shock absorbing layer for
A second base material having a first main surface and a second main surface and a second main surface in contact with the first main surface of the second base material are provided to reduce the impact during transfer of a semiconductor chip. A second transfer substrate preparation step for preparing a second transfer substrate provided with at least a second shock absorbing layer for
A semiconductor chip holding step of holding a semiconductor chip on the first main surface of the first shock absorbing layer in the first transfer substrate, and
A transfer in which the first main surface of the first shock absorbing layer in the first transfer substrate and the first main surface of the second shock absorbing layer in the second transfer substrate are arranged so as to face each other with a gap. Board placement process and
A laser beam is irradiated from the second main surface side of the first base material in the first transfer substrate, and the semiconductor chip is separated from the first main surface of the first shock absorbing layer to separate the semiconductor chip from the second transfer substrate. A transfer method comprising a transfer step of moving the second shock absorbing layer to the first main surface for transfer. A transfer method for transferring semiconductor chips,
The first base material having the first main surface and the second main surface and the first main surface of the first base material are provided in contact with the second main surface to alleviate the impact at the time of transfer of the semiconductor chip. A first shock absorbing layer for holding a semiconductor chip, and a first chip fixing layer for holding a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the first shock absorbing layer. The first transfer substrate preparation process for preparing the transfer substrate, and
A second base material having a first main surface and a second main surface and a second main surface in contact with the first main surface of the second base material are provided to reduce the impact during transfer of a semiconductor chip. A second shock absorbing layer for holding a semiconductor chip, and a second chip fixing layer for holding a semiconductor chip, which is provided with a second main surface in contact with the first main surface of the second shock absorbing layer. The second transfer substrate preparation process for preparing the transfer substrate, and
A semiconductor chip holding step of holding a semiconductor chip on the first main surface of the first chip fixing layer in the first transfer substrate, and
A transfer in which the first main surface of the first chip fixing layer on the first transfer substrate and the first main surface of the second chip fixing layer on the second transfer substrate are arranged so as to face each other with a gap. Board placement process and
A laser beam is irradiated from the second main surface side of the first base material in the first transfer substrate to separate the semiconductor chip and reach the first main surface of the second chip fixing layer of the second transfer substrate. A transfer method characterized by comprising a transfer step of moving and transferring.

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