Laser system, laser processing method, and method for manufacturing interposer

Abstract

A laser system is provided with: a pump laser device that outputs pump light of a first wavelength; a signal laser device that outputs signal light of a second wavelength longer than the first wavelength; an optical parametric crystal that transmits the pump light and the signal light and outputs amplified light of a second wavelength; and the photon flux density control mechanism is used for controlling the photon flux density of the pump light and the signal light, so that the sum of the photon flux density of the pump light and the photon flux density of the signal light at the input end of the optical parametric crystal becomes the intensity distribution of the amplified light of the second wavelength which is monotonically reduced from the center to the outside.

Description

Technical Field

[0001] This disclosure relates to laser systems, laser processing methods, and methods for manufacturing intermediate layers. Background Technology

[0002] In recent years, with the miniaturization and high integration of semiconductor integrated circuits, there has been a demand for higher resolution in semiconductor exposure equipment. Therefore, efforts are underway to shorten the wavelength of light emitted from the exposure light source. For example, as gas laser devices for exposure, KrF excimer lasers using lasers with an output wavelength of approximately 248 nm and ArF excimer lasers using lasers with an output wavelength of approximately 193 nm are being developed.

[0003] The spectral linewidth of the naturally oscillating light from KrF and ArF excimer lasers is as wide as 350 pm to 400 pm. Therefore, if the projection lens is made of a material that allows ultraviolet light, such as that from KrF and ArF lasers, to pass through, chromatic aberration may sometimes occur. As a result, the resolution may be reduced. Therefore, it is necessary to narrow the spectral linewidth of the laser output from the gas laser device to a level where chromatic aberration can be ignored. Thus, in order to narrow the spectral linewidth, the laser resonator of a gas laser device sometimes includes a line-narrowing module (LNM) containing narrowing elements (etalon, grating, etc.). Hereinafter, gas laser devices with narrowed spectral linewidths will be referred to as narrow-bandgap gas laser devices.

[0004] Existing technical documents

[0005] Patent documents

[0006] [Patent Document 1] Japanese Patent No. 3471188

[0007] [Patent Document 2] International Publication No. 2023 / 145524 Summary of the Invention

[0008] A laser system according to one aspect of this disclosure comprises: a pump laser device that outputs pump light of a first wavelength; a signal laser device that outputs signal light of a second wavelength longer than the first wavelength; an optical parametric crystal that allows the pump light and signal light to pass through and outputs amplified light of the second wavelength; and a photon flux density control mechanism that controls the photon flux density of the pump light and signal light and adjusts the sum of the photon flux densities of the pump light and signal light at the input end of the optical parametric crystal so that the intensity distribution of the amplified light of the second wavelength is a monotonically decreasing intensity distribution from the center outward.

[0009] Another aspect of this disclosure discloses a laser processing method comprising the following steps: generating a second wavelength laser using a laser system; performing wavelength conversion on the second wavelength laser to generate an ultraviolet laser; and irradiating an irradiated object with the ultraviolet laser to process the irradiated object. The laser system comprises: a pump laser device that outputs a first wavelength pump light; a signal laser device that outputs a second wavelength signal light longer than the first wavelength; an optical parametric crystal that allows the pump light and signal light to pass through and outputs amplified light of the second wavelength; and a photon flux density control mechanism that controls the photon flux density of the pump light and signal light, adjusting the sum of the photon flux densities of the pump light and signal light at the input end of the optical parametric crystal, so that the intensity distribution of the amplified light of the second wavelength becomes a monotonically decreasing intensity distribution from the center outwards.

[0010] Another aspect of this disclosure describes a method for manufacturing an intermediate layer, comprising the following steps: generating a second wavelength laser using a laser system; performing wavelength conversion on the second wavelength laser to generate an ultraviolet laser; and irradiating the ultraviolet laser onto an irradiated object to manufacture the intermediate layer. The laser system includes: a pump laser device that outputs a first wavelength pump light; a signal laser device that outputs a second wavelength signal light longer than the first wavelength; an optical parametric crystal that allows the pump light and signal light to pass through and outputs amplified light of the second wavelength; and a photon flux density control mechanism that controls the photon flux density of the pump light and signal light, adjusting the sum of the photon flux densities of the pump light and signal light at the input end of the optical parametric crystal to make the intensity distribution of the amplified light of the second wavelength a monotonically decreasing intensity distribution from the center outwards. Attached Figure Description

[0011] The following description, by way of example only, refers to the accompanying drawings to illustrate several embodiments of this disclosure.

[0012] Figure 1 The structure of the comparative example laser system is shown in outline.

[0013] Figure 2 The structure of an optical parametric amplifier (OPA) is shown in outline.

[0014] Figure 3 The structure of the beam diameter adjustment optical system of the OPA is shown in outline.

[0015] Figure 4 The magnified light is shown as a multi-ringed distribution.

[0016] Figure 5 The structure of the OPA in Implementation 1 is shown in outline.

[0017] Figure 6 The structure of the beam power adjustment system of the OPA in Embodiment 1 is illustrated schematically.

[0018] Figure 7 This shows that the amplified light was suppressed to form a multi-ring distribution.

[0019] Figure 8 It is a graph that shows the conversion efficiency of amplified light through a heat map.

[0020] Figure 9 The structure of the laser processing system and intermediate layer processing apparatus of Embodiment 2 is shown in a schematic diagram.

[0021] Figure 10 The structure of the electronic device is shown schematically.

[0022] Figure 11 This is a flowchart illustrating a method for manufacturing electronic devices. Detailed Implementation

[0023] -Table of contents-

[0024] 1. Comparative laser system and amplification system

[0025] 1.1 Overview of the Laser System

[0026] 1.1.1 Structure

[0027] 1.1.2 Actions

[0028] 1.2 Overview of the Amplification System

[0029] 1.2.1 Structure

[0030] 1.2.2 Actions

[0031] 1.2.3 Functions and Effects

[0032] 2. Research Topic

[0033] 3. Implementation Method 1

[0034] 3.1 Structure

[0035] 3.2 Actions

[0036] 3.3 Derivation of Conditions

[0037] 3.4 Functions and Effects

[0038] 4. Implementation Method 2

[0039] 4.1 Structure of the Laser Processing System

[0040] 4.2 Operation of the laser processing system

[0041] 5. Manufacturing method of electronic devices including an interposer layer

[0042] 5.1 Structural Examples of Electronic Devices

[0043] 5.2 Manufacturing methods for electronic devices

[0044] 6. Other

[0045] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, not all structures and operations described in each embodiment are necessary for the structures and operations of the present disclosure. Furthermore, the same reference numerals are used to refer to the same constituent elements, and repeated descriptions are omitted.

[0046] 1. Comparative laser system and amplification system

[0047] 1.1 Overview of the Laser System

[0048] 1.1.1 Structure

[0049] Figure 1 The structure of the comparative example laser system 20 is shown in a schematic diagram. The comparative examples in this disclosure are those known only to the applicant and are not publicly known examples endorsed by the applicant.

[0050] The laser system 20 includes a signal laser device 210, an amplification system 230, a pump laser device 270, and a wavelength conversion system 280. The laser system 20 outputs pulsed laser light with a wavelength of approximately 193.4 nm.

[0051] The signal laser device 210 includes a semiconductor laser 211 and a solid-state amplifier 213. The semiconductor laser 211 oscillates in a single longitudinal mode (CW) at a wavelength of about 1553 nm or about 1407 nm.

[0052] Solid-state amplifier 213 includes a semiconductor optical amplifier (SOA) that amplifies the CW oscillating laser output from semiconductor laser 211.

[0053] The pumped laser device 270 includes a semiconductor laser 271, a solid-state amplifier 273, an LBO crystal 275 as a nonlinear optical crystal, and a dichroic mirror (DM) 277. "LBO" is represented by the chemical formula LiB3O5.

[0054] Semiconductor laser 271 includes a semiconductor laser that oscillates in CW mode in a single longitudinal mode at a wavelength of about 1030 nm or about 1064 nm. Solid-state amplifier 273 is an amplifier that includes an SOA (not shown), a Yb fiber amplifier, or a Yb:YAG crystal.

[0055] The LBO crystal 275 converts a laser wavelength of approximately 1030 nm into second harmonic light (wavelength approximately 515 nm). The following explanation addresses the cases where semiconductor laser 211 outputs laser light with a wavelength of approximately 1553 nm and semiconductor laser 271 outputs laser light with a wavelength of approximately 1030 nm. Furthermore, even when semiconductor laser 211 outputs laser light with a wavelength of approximately 1407 nm and semiconductor laser 271 outputs laser light with a wavelength of approximately 1064 nm, the laser system 20 still outputs pulsed laser light with a wavelength of approximately 193.4 nm.

[0056] The DM277 is positioned in the optical path after the LBO crystal 275, allowing pulsed laser light with a wavelength of approximately 515 nm to pass through with high transmittance and pulsed laser light with a wavelength of approximately 1030 nm to be reflected with high reflectance. The pulsed laser light with a wavelength of approximately 1030 nm, which is reflected with high reflectance by the DM277, is then used as pump laser light and incident on the amplification system 230.

[0057] The amplification system 230 includes an optical parametric amplifier (OPA) 240. The OPA 240 is, for example, an amplifier containing a PPLN (Periodically Poled Lithium Niobate) crystal or a PPKTP (Periodically Poled KTP) crystal. The OPA 240 pulses the signal laser by inputting both the pump laser and the signal laser.

[0058] Wavelength conversion system 280 includes DM283 and CLBO crystals 281, 285, and 287 as nonlinear optical crystals. "CLBO" is derived from the chemical formula CsLiB6O. 10 The CLBO crystals 281, 285, and 287 are respectively disposed on a rotating stage containing a piezoelectric element (not shown), configured to change the incident angle of each crystal at high speed.

[0059] The CLBO crystal 281 converts the wavelength of second harmonic light (wavelength approximately 515 nm) into that of fourth harmonic light (wavelength approximately 258 nm).

[0060] DM283 is a structure that reflects the pulsed laser output from the amplification system 230 with high reflectivity and transmits the pulsed laser output from the CLBO crystal 281 with high transmittance, and is configured to allow the two pulsed lasers to be incident coaxially on the CLBO crystal 285.

[0061] The CLBO crystal 285 and CLBO crystal 287 are connected in series to output a pulsed laser with a wavelength of approximately 193.4 nm by generating a sum frequency twice.

[0062] The laser system 20 is controlled by a solid-state laser processor 40 and a laser processor 10. The processor of this disclosure is a processing device including a storage device storing a control program and a CPU (Central Processing Unit) that executes the control program. The processor may include a GPU (Graphics Processing Unit). The processor is specifically configured or programmed to perform the various processes included in this disclosure.

[0063] The solid-state laser processor 40 is connected to the signal laser device 210, the pump laser device 270, and the wavelength conversion system 280. The laser processor 10 is connected to the solid-state laser processor 40. Furthermore, the processing functions of the solid-state laser processor 40 can also be installed on the laser processor 10.

[0064] 1.1.2 Actions

[0065] The solid-state laser processor 40 controls the current value of the semiconductor laser 271 of the pump laser device 270 to make it oscillate in a CW manner, outputting a CW laser with a wavelength of approximately 1030 nm. Furthermore, the solid-state laser processor 40 uses the SOA of the solid-state amplifier 273 to pulse the CW laser, and performs pulse amplification through the amplifier of the solid-state amplifier 273 that includes a Yb fiber amplifier or a Yb:YAG crystal.

[0066] The LBO crystal 275 converts pulsed laser light with a wavelength of approximately 1030 nm into second harmonic light with a wavelength of approximately 515 nm. The second harmonic light with a wavelength of approximately 515 nm passes through the DM277 with high transmittance and is incident on the wavelength conversion system 280.

[0067] Here, DM277 reflects the pulsed laser with a wavelength of approximately 1030 nm that has not been wavelength-converted by LBO crystal 275 with high reflectivity, and the pump laser of amplification system 230 is incident on OPA240.

[0068] Furthermore, the solid-state laser processor 40 controls the current value of the semiconductor laser 211 to output a CW laser with a wavelength of approximately 1553 nm. Then, the solid-state laser processor 40 amplifies the laser using a solid-state amplifier 213, and outputs the amplified CW laser with a wavelength of approximately 1553 nm from the signal laser device 210.

[0069] The OPA240 of the amplification system 230 is fed with a pulsed laser with a wavelength of approximately 1030 nm after being reflected by the DM277 as a pump laser, and a CW laser with a wavelength of approximately 1553 nm output from the signal laser device 210 as a signal laser, thereby outputting an amplified pulsed laser with a wavelength of approximately 1553 nm.

[0070] A first pulsed laser with a wavelength of approximately 1553 nm, output from amplification system 230, and a second pulsed laser with a wavelength of approximately 515 nm, output from pump laser device 270, are input to wavelength conversion system 280. The second pulsed laser is converted into ultraviolet light with a wavelength of approximately 258 nm, i.e., pulsed laser, by CLBO crystal 281. Then, the sum of the first pulsed laser and the ultraviolet light with a wavelength of approximately 258 nm is generated by CLBO crystal 285, and after wavelength conversion to approximately 221 nm, a pulsed laser with a wavelength of approximately 193.4 nm is further output by summing the wavelength of the first pulsed laser and the ultraviolet light with a wavelength of approximately 1553 nm in CLBO crystal 287.

[0071] The generated pulsed laser with a wavelength of approximately 193.4 nm can be amplified using an excimer amplifier (not shown).

[0072] 1.2 Overview of the Amplification System

[0073] 1.2.1 Structure

[0074] Figure 2 The structure of OPA240 is shown in outline. OPA240 includes: PPLN crystals 241 and 243; beam diameter adjustment optical systems 245, 247, 249 and 251; DMs 253, 255, 257 and 259; light reduction units 261 and 263; optical path mirrors 262, 266 and 268 for optical path formation; and a beam splitter 264.

[0075] Figure 3 The structure of the beam diameter adjustment optical system 245 of OPA240 is schematically shown. The beam diameter adjustment optical system 245 includes multiple lenses 242, 242. Lenses 242, 242 are held in place by supports 244, 244 respectively, and are arranged opposite each other on a base plate 246. The beam diameter adjustment optical system 245 is configured to adjust the distance between lenses 242, 242. Other beam diameter adjustment optical systems 247, 249, 251 may also have the same structure.

[0076] The beam diameter adjustment optical systems 245 and 247 are configured to make the beam waist diameters of the signal laser and the pump laser incident on the PPLN crystal 241 equal. The beam diameter adjustment optical system 245 is disposed in the optical path of the signal laser, and the beam diameter adjustment optical system 247 is disposed in the optical path of the pump laser.

[0077] The beam diameter adjustment optical systems 249 and 251 are configured such that the beam waist diameters of the signal laser and the pump laser incident on the PPLN crystal 243 are the same. The beam diameter adjustment optical system 249 is positioned in the optical path of the signal laser between the PPLN crystal 241 and the PPLN crystal 243, and the beam diameter adjustment optical system 251 is positioned in the optical path of the pump laser.

[0078] The beam diameter adjustment optical systems 245, 247, 249, and 251 can, for example, be structures that maintain the inter-lens distance of a pair of opposing lenses 242, 242 (see reference). Figure 3 The beam diameter adjustment optical systems 245, 247, 249, and 251 can adjust the beam waist position and beam waist diameter of both the signal laser and the pump laser.

[0079] Beam splitter 264 is configured in the optical path of the pump laser such that the pump laser from pump laser device 270 is branched and the pump lasers are respectively incident on the beam diameter adjustment optical systems 247 and 251. Optical path mirror 266 is configured to reflect the pump laser reflected by beam splitter 264 and guide it to beam diameter adjustment optical system 251.

[0080] DM253 and 257 are dichroic mirrors used to combine signal lasers and pump lasers. For example, they reflect light with a wavelength of approximately 1553 nm with high reflectivity, while allowing light with a wavelength of approximately 1030 nm to pass through with high transmittance.

[0081] DM255 and 259 are dichroic mirrors used to separate pump laser and idler light from the output light of PPLN crystals 241 and 243. For example, DM255 and DM259 reflect light with high reflectivity at a wavelength of about 1553 nm, while allowing light with a wavelength of about 1030 nm and light with a wavelength of about 3070 nm to pass through with high transmittance.

[0082] The light reduction units 261 and 263 absorb the pump laser and idler light separated by DM255 and 259. Additionally, multiple optical path mirrors 262, 266, and 268 are configured to form the optical path of the OPA240.

[0083] 1.2.2 Actions

[0084] The signal laser and the pump laser are incident on the PPLN crystal 241 via beam diameter adjustment optical systems 245 and 247, respectively. At this time, the beam waist positions of the signal laser and the pump laser incident on the PPLN crystal 241 are consistent with each other, and the beam waist diameters of the two coaxially incident lasers inside the PPLN crystal 241 are set to be the same for the pump laser and the signal laser.

[0085] When the signal laser and pump laser are incident on the PPLN crystal 241, optical parametric amplification occurs in the PPLN crystal 241, generating amplified light and idler light. The amplified light has the same wavelength as the signal laser, about 1553nm, and the idler light corresponds to the difference frequency of the signal laser and pump laser, with a wavelength of about 3070nm.

[0086] The pump laser and idler light output from PPLN crystal 241 are absorbed and processed by attenuation unit 261 via DM 255. Light with a wavelength of approximately 1553 nm, including amplified light and signal laser, output from PPLN crystal 241, is incident on PPLN crystal 243 via DM 255, beam diameter adjustment optical system 249, and DM 257. The laser with a wavelength of approximately 1553 nm output from PPLN crystal 241 becomes the signal laser input to PPLN crystal 243.

[0087] Furthermore, the pump laser reflected by beam splitter 264 is incident on PPLN crystal 243 via optical path mirror 266, beam diameter adjustment optical system 251, and DM 257. At this time, the beam waist diameters of the pump laser and signal laser within PPLN crystal 243 are set to be the same. Optical parametric amplification is generated in PPLN crystal 243, producing amplified light and idler light. The amplified light has the same wavelength as the signal laser, approximately 1553 nm, while the idler light corresponds to the difference frequency between the signal laser and the pump laser, with a wavelength of approximately 3070 nm.

[0088] The pump laser and idler light output from PPLN crystal 243 are absorbed and processed by attenuation unit 263 via DM259. The amplified light output from PPLN crystal 243 is used in wavelength conversion system 280 (see reference). Figure 1 The sum frequency is generated in the CLBO crystal 285.

[0089] 1.2.3 Functions and Effects

[0090] The beam waist diameters within the PPLN crystals 241 and 243 are adjusted to be identical for both the pump laser and the signal laser. This is because, at the beam waist position where the beam is considered a plane wave, beam waists of equal diameter are set near the crystal center to expand the region where phase matching can be achieved efficiently. As a result, the mode matching of the signal laser and the pump laser improves, resulting in strongly amplified light.

[0091] 2. Research Topic

[0092] In the amplification system 230 using the OPA240, multiple ring-shaped distributions may occur depending on the conditions under which the signal light and pump light are incident on the crystal. For example, under certain conditions, the amplified light amplified by the OPA240 may sometimes exhibit a multiple ring-shaped distribution. Figure 4 It is a magnified diagram showing the distribution of light in multiple rings.

[0093] The amplified light, distributed in multiple rings, has poor focusing properties, and in subsequent wavelength conversion and amplification, only about half of the OPA240 output can sometimes be utilized. Therefore, a laser system is required to suppress the multi-ring distribution of the amplified light from the OPA240.

[0094] 3. Implementation Method 1

[0095] 3.1 Structure

[0096] The laser system 20 of embodiment 1 includes Figure 5 The OPA240A shown is used to replace Figure 2 The OPA240 shown. Other structures can be used with... Figure 1 same.

[0097] Figure 5 The structure of OPA240A according to Embodiment 1 is shown in outline. Regarding... Figure 5 The structure shown illustrates the relationship with... Figure 2 The differences are as follows. The OPA240A includes beam power adjustment systems 265, 267, and 269. Each beam power adjustment system includes, for example, a λ / 2 plate (HWP) 248, a polarization beam splitter (PBS) 252, a power meter 256, or a light reduction unit (see reference). Figure 6 ).

[0098] Figure 6 The structure of the beam power adjustment system 265, 267, and 269 of the OPA240A in Embodiment 1 is schematically shown. The HWP248 is held in a rotating bracket 250 in a manner that allows it to rotate around the optical axis. The PBS252 is held by a bracket 254. The PBS252 can be cubic or planar. The HWP248 and PBS252 are sequentially arranged in the optical path, and the power meter 256 or a light-reducing unit is arranged in the reflected optical path of the PBS252.

[0099] Beam power adjustment systems 265 and 267 are respectively configured in the optical paths of the signal light and pump light incident on the PPLN crystal 241, and adjust the power of the signal light and pump light incident on the PPLN crystal 241. The intensity distribution of the signal light and pump light incident on the PPLN crystal 241 is Gaussian.

[0100] The beam power adjustment system 269 is configured in the optical path of the pump light incident on the PPLN crystal 243 to adjust the power of the pump light incident on the PPLN crystal 243.

[0101] Other structures can be combined with Figure 2 same.

[0102] 3.2 Actions

[0103] The beam power adjustment systems 265, 267, and 269 can adjust the polarization component of the light transmitted through the PBS 252 by rotating the HWP 248. At this time, the adjustment can be made while measuring the power of the polarization component reflected by the PBS 252 using the power meter 256, or the power meter 256 can be temporarily positioned in the transmission path of the PBS 252 to adjust the power of the transmitted laser.

[0104] By using beam power adjustment systems 265, 267, 269 and beam diameter adjustment optical systems 245, 247, 249, 251, the sum of the photon flux densities of the input signal light and the input pump light in PPLN crystal 241 and PPLN crystal 243 is adjusted to satisfy the following equation (1) at the center of the beam.

[0105] [Number 1]

[0106]

[0107] The derivation of equation (1) and the meaning of each symbol will be described later.

[0108] Once the adjustment is complete, the rotation angle of HWP248 can be fixed, and the light reduction unit can be configured to replace the power meter 256, or the power meter 256 can be removed from the transmission light path.

[0109] A wavelength of approximately 1030 nm is an example of a "first wavelength" in this disclosure, and a wavelength of approximately 1553 nm is an example of a "second wavelength" in this disclosure. PPLN crystals 241 and 243 are examples of "optical parametric crystals" in this disclosure. The combination of beam power adjustment systems 265 and 267 and beam diameter adjustment optical systems 245 and 247 is an example of a "photon flux density control mechanism" in this invention. Beam diameter adjustment optical system 245 is an example of a "first focusing optical system" in this disclosure, and beam diameter adjustment optical system 247 is an example of a "second focusing optical system" in this disclosure. Beam power adjustment system 265 is an example of a "first power controller" in this disclosure, and beam power adjustment system 267 is an example of a "second power controller" in this disclosure. Lenses 242 and 242 are examples of a "lens pair" in this invention. HWP248 is an example of a "λ / 2 plate" in this disclosure. PBS252 is an example of a "polarization beam splitter" in this disclosure. Semiconductor laser 271 is an example of a "first semiconductor laser" in this disclosure. Solid-state amplifier 273 is an example of a "first solid-state amplifier" in this disclosure. LBO275 is an example of a "first nonlinear optical crystal" in this disclosure. Semiconductor laser 211 is an example of a "second semiconductor laser" in this disclosure. Solid-state amplifier 213 is an example of a "second solid-state amplifier" in this disclosure. CLBO281 is an example of a "second nonlinear optical crystal" in this disclosure. CLBO285 is an example of a "third nonlinear optical crystal" in this disclosure. CLBO287 is an example of a "fourth nonlinear optical crystal" in this disclosure.

[0110] 3.3 Derivation of Conditions

[0111] In the plane wave approximation, the change of the photoelectric field based on nonlinear optical effects is expressed as follows (2) to (4) (for example, see Chapter 8, Section 4 of "Photoelectron Deployment" by Yelia-Iche (Maruzen Publishing).

[0112] [Number 2]

[0113]

[0114] Here, the subscripts s, i, and p represent the signal light, idler light, and pump light, respectively. Additionally, when x is set to an arbitrary complex number, x* represents the complex conjugate of x. Furthermore, phase mismatch...

[0115] Δk = 0.

[0116] The meanings of each symbol are as follows.

[0117] [Number 3]

[0118] C: Speed ​​of light

[0119] ε0: Dielectric constant of vacuum

[0120] μ0: Permeability of vacuum

[0121] Planck's constant / 2π

[0122] ω s ω i ω p Angular frequency of each light source

[0123] E s E i E p Complex amplitude of the electric field of each light

[0124] I s I i I p : Light intensity of each light

[0125] j s j i j p Photon flux density of each light source

[0126] d eff Effective nonlinear constant of a nonlinear optical crystal

[0127] L: Crystal length of the nonlinear optical crystal

[0128] n s n i n p The refractive index of a nonlinear optical crystal at various wavelengths.

[0129] z: Position coordinates of the direction of light propagation.

[0130] As initial conditions for OPA, if we consider z = 0, E S =E S,in E i =0, E p =E p,in In the case of the given condition, the solution to the differential equation is expressed using Jacobi's elliptic functions sn, cn, dn as shown in equations (5) to (9).

[0131] [Number 4]

[0132]

[0133] [Number 5]

[0134]

[0135] [Number 6]

[0136]

[0137] [Number 7]

[0138]

[0139] [Number 8]

[0140]

[0141] Jacobi's elliptic functions sn, cn, and dn are defined by equations (10) to (12).

[0142] [Number 9]

[0143] sn(u|m)=sin(am(u|m)) (10)

[0144] cn(u|m)=cos(am(u|m)) (11)

[0145]

[0146] The amplitude am is the inverse function of the first type of elliptic integral F, and in the following equation (13), it satisfies the following equation (14).

[0147] [Number 10]

[0148] u=F(φ|m) (13)

[0149] [Number 11]

[0150] φ=am(u|m) (14)

[0151] The first type of elliptic integral F is given by the following equation (15) when 0 < m < 1.

[0152] [Number 12]

[0153]

[0154] The light intensity I of the signal light s The complex amplitude E of the electric field of the signal light s The relationship is represented by the following formula (16).

[0155] [Number 13]

[0156]

[0157] Pump light intensity I p The complex amplitude E of the electric field of the pump light p The relationship is represented by the following formula (17).

[0158] [Number 14]

[0159]

[0160] In particular, the output light intensity I of the signal light when z = L s,out The light intensity I of the signal light and pump light at z=0 s,in I p,in It is represented by the following formulas (18) to (20).

[0161] [Number 15]

[0162]

[0163] [Number 16]

[0164]

[0165] [Number 17]

[0166]

[0167] Here, we consider a Gaussian beam near the beam waist as the input light. The change in the beam diameter of the input light can be neglected over the entire length of the crystal, approximating a result that can be calculated using the plane wave approximation.

[0168] That is, the distribution of the output light depends on the distribution of the input light, and is approximately represented by the following equations (21) to (23).

[0169] [Number 18]

[0170]

[0171] [Number 19]

[0172]

[0173] [Number 20]

[0174]

[0175] Here, x and y are position coordinates that are orthogonal to each other in a plane perpendicular to the direction of light propagation z.

[0176] In the following equation (24), with respect to u, it has a period of 2K(m), which increases when 0 < u < K(m) and decreases when K(m) < u < 2K(m).

[0177] [Number 21]

[0178] 1 / dn 2 (u|m) (24)

[0179] Here, K is the first type of complete elliptic integral, denoted by equation (25).

[0180] [Number 22]

[0181]

[0182] The light intensity of a Gaussian beam decreases from the center outwards. Therefore, if the condition u≤K(m) can be satisfied at the center of the beam, the distribution of the output light will also decrease from the center outwards, which is considered to prevent the generation of multiple ring-shaped distributions. Figure 7 This shows the amplified light from the OPA240A, which has suppressed the distribution into multiple rings. (Example) Figure 7 As shown, the intensity distribution of the amplified light amplified by the OPA240A decreases monotonically from the center outwards.

[0183] According to u≤K(m), the following equation (26) can be satisfied at the beam center.

[0184] [Number 23]

[0185]

[0186] When using the photon flux density j expressed by the following equation (27) s j p When equation (26) is rearranged, equation (1) is obtained.

[0187] [Number 24]

[0188]

[0189] [Number 25]

[0190]

[0191] 3.4 Functions and Effects

[0192] Figure 8 It is a graph that uses heat maps to show the conversion efficiency of amplified light. Figure 8 The horizontal axis represents the intensity of the input signal light (in arbitrary units), and the vertical axis represents the intensity of the input pump light (in arbitrary units). Figure 8 On the right, the legend of the heatmap is shown together with the definition of conversion efficiency. Conversion efficiency is calculated with the intensity of the input pump light (in arbitrary units) as the denominator and the difference between the intensity of the output signal light (in arbitrary units) and the intensity of the input signal light (in arbitrary units) as the numerator.

[0193] For example, when in Figure 8 When selecting the light intensity at the beam center in the upper right elliptical area of ​​the graph shown, the input intensity weakens as the beam moves outwards, resulting in a multi-ringed distribution of conversion efficiency (see reference). Figure 4 ).

[0194] In contrast, if in Figure 8 The light intensity at the center of the beam is selected in the lower left elliptical area of ​​the graph shown. As the beam moves towards the outer periphery, the conversion efficiency does not increase but only decreases. Figure 8 The lower left elliptical region is the region that satisfies the condition of equation (1).

[0195] In the OPA240A of embodiment 1, by Figure 5 The structure adjusts the sum of the photon flux densities of the input signal light and the input pump light to satisfy the condition of equation (1). Thus, according to embodiment 1, it is possible to obtain amplified light that suppresses the distribution of multiple rings.

[0196] Here, considering the structure of adjusting the output of semiconductor laser 211 and solid-state amplifier 213 without relying on beam power adjustment systems 265 and 267, while adjusting the power of the signal light and pump light respectively. However, based on these structures, the thermal lensing effect of the crystal may change due to the change in the thermal input conditions of the crystal of solid-state amplifier 213.

[0197] When the thermal lensing effect of the crystal changes, the intensity distribution and divergence angle of the amplified light amplified by the solid-state amplifier 213 may change. When the intensity distribution of the amplified light from the solid-state amplifier 213 changes, the distribution of the amplified light from the OPA240 also changes. When the divergence angle of the amplified light from the solid-state amplifier 213 changes, the beam waist position of each input light in the OPA240 changes, sometimes resulting in a decrease in amplification efficiency.

[0198] Therefore, a structure is required that can adjust the power while maintaining the intensity distribution and divergence angle of the amplified light of the solid-state amplifier 213. Figure 5 The structure is one example. Therefore, as long as the power can be adjusted while maintaining the intensity distribution and divergence angle, it can also be adjusted by replacing the ND filter, etc.

[0199] 4. Implementation Method 2

[0200] 4.1 Structure of the Laser Processing System

[0201] Figure 9 The structure of the laser processing system 1 of Embodiment 2 is shown in a schematic diagram. Figure 9 The laser processing system 1 shown includes a laser processor 10, a laser system 20, a laser processing device 30, a solid-state laser processor 40, and an optical path tube 60. The laser processing system 1 can also be used for drilling holes in glass used as an interlayer.

[0202] The laser processing apparatus 30 includes a laser processing processor 31, an irradiation optical system 33, a frame 37, an XYZ stage 39, and a worktable 41 on which the object to be irradiated 50 is placed.

[0203] The illumination optical system 33 includes high reflectance mirrors (HM) 331, 333, 335, attenuator 337, illumination optical system 339, photomask 341, projection optical system 343, window 345, and housing 347.

[0204] HM331, HM333, and HM335 are fixed within housing 347 to various brackets (not shown) and configured to direct the laser output from laser system 20 to illumination optics system 339.

[0205] Attenuator 337 is positioned in the optical path between HM331 and HM333. Attenuator 337 includes two partial mirrors (not shown) and a rotating stage (not shown) for changing the incident angle of the partial mirrors.

[0206] The illumination optics system 339 is fixed to the holder 348 and configured with a pair of photomasks 341 for Köhler illumination.

[0207] Photomask 341 is, for example, a mask on which a pattern of a multilayer metal or dielectric film is formed on a synthetic quartz substrate that allows ultraviolet light to pass through.

[0208] The projection optical system 343 is fixed to the bracket 349 and configured such that the beam waist of the laser beam focused through the window 345 can be focused onto a position in the irradiated object 50 at a predetermined depth ΔZsfw from the surface on the incident side. The projection optical system 343 may also be a single lens or a group of lenses with aberration correction.

[0209] The window 345 is located in the optical path between the projection optical system 343 and the object being illuminated 50, and is disposed in the housing 347 through a hole such as an O-ring (not shown).

[0210] The housing 347 is provided with an inlet 351 and an outlet 353 for N2 gas, which are sealed using an O-ring (not shown) or the like to prevent external gas from mixing into the housing 347.

[0211] An illumination optical system 33 and an XYZ stage 39 are fixed on the frame 37, and a worktable 41 is arranged on the XYZ stage 39. The object to be irradiated 50 is fixed on the worktable 41. The object to be irradiated 50 during the fabrication of the interposer layer can be, for example, a glass substrate such as quartz glass.

[0212] Here, the space between window 345 and the object being irradiated 50 is air.

[0213] The optical path tube 60 is positioned between the laser system 20 and the irradiation optical system 33 and is sealed by an O-ring or similar device (not shown). The optical path tube 60 is also purged using N2 purging gas.

[0214] 4.2 Operation of the laser processing system

[0215] The laser processing processor 31 controls the position of the object 50 to be irradiated via the XYZ stage 39, so that the beam waist of the laser focused by the irradiation optical system 33 is located at a specified depth from the surface of the object 50, and the focusing diameter becomes a specified focusing diameter.

[0216] Next, the laser processing processor 31 sends the target pulse energy Et to the laser processor 10 and controls the transmittance T of the attenuator 337 so that the flux of the irradiated object 50 becomes the target flux Fm.

[0217] The laser processing processor 31 sends a light emission trigger signal with a specified number of pulses Nm to the laser processor 10 at a specified repetition frequency fm.

[0218] When the laser processor 10 receives the emission trigger signal Tr, it controls the laser system 20 to become the target pulse energy Et.

[0219] The laser processor 10 outputs laser light synchronously with the light emission trigger Tr signal, and the laser light is incident on the laser processing device 30.

[0220] The laser is reflected by HM331 with high reflectivity, passes through attenuator 337 with transmittance T, and is incident on HM333.

[0221] The laser light reflected by HM333 with high reflectivity is incident on the illumination optics 339 via HM335.

[0222] The laser light transmitted through the illumination optical system 339 is focused through the window 345 onto a position in the irradiated object 50 at a predetermined depth from the surface on the incident side.

[0223] As a result, laser-based hole-making is performed by irradiating the object at a specified depth of 50 with a flux density of Fm, a repetition frequency of fm, and a pulse number of Nm.

[0224] Furthermore, the device can independently possess the laser processor 10, the laser processing processor 31, and the solid-state laser processor 40, or any processor can have all three functions. Additionally, the device possessing the functions of the laser processor 10, the laser processing processor 31, and the solid-state laser processor 40 can be simply referred to as a processor.

[0225] 5. Manufacturing method of electronic devices including an interposer layer

[0226] 5.1 Examples of electronic device structures

[0227] Figure 10 The structure of the electronic device 100 is shown schematically. Figure 10The illustrated electronic device 100 includes an integrated circuit chip 101, an interposer 102, and a circuit substrate 103. The integrated circuit chip 101 is, for example, a chip-shaped integrated circuit substrate on a silicon substrate on which integrated circuits are formed. Multiple bumps 101b electrically connected to the integrated circuits are provided on the integrated circuit chip 101.

[0228] Intermediate layer 102 has an insulating glass substrate with a plurality of through holes, and a conductor electrically connecting the front and back of the glass substrate is disposed in each through hole.

[0229] Multiple pads are formed on one side of the interposer 102, which are connected to bumps 101b disposed on the integrated circuit chip 101. Each pad is electrically connected to any conductor in the conductor within the through-hole. Multiple bumps 102b are disposed on the other side of the interposer 102, and each bump 102b is electrically connected to any conductor in the conductor within the through-hole.

[0230] A number of pads are formed on one side of the circuit board 103, which are connected to the respective bumps 102b. In addition, the circuit board 103 has a plurality of terminals that are electrically connected to these pads.

[0231] 5.2 Manufacturing methods of electronic devices

[0232] Figure 11 A flowchart illustrating a method for manufacturing electronic device 100. (e.g.) Figure 11 As shown, the manufacturing method of the electronic device 100 in this description includes a first bonding process SP1 and a second bonding process SP2.

[0233] In the first bonding process SP1, the integrated circuit chip 101 is bonded to the interposer 102. Specifically, each bump 101b of the integrated circuit chip 101 is disposed on each pad of the interposer 102, and the bumps 101b and the pads are electrically connected to each other. Therefore, the integrated circuit chip 101 and the interposer 102 are electrically connected to each other.

[0234] In the second bonding process SP2, the interposer 102 is bonded to the circuit board 103. Specifically, bumps 102b of the interposer 102 are disposed on pads of the circuit board 103, and the bumps 102b and the pads are electrically connected to each other. Therefore, the integrated circuit chip 101 is electrically connected to the circuit board 103 via the interposer 102. After the above processes, the electronic device 100 is manufactured.

[0235] 6. Other

[0236] The foregoing description is not limiting but merely illustrative. Therefore, it will be apparent to those skilled in the art that modifications can be made to the embodiments of this disclosure without departing from the claims. Furthermore, it will be apparent to those skilled in the art that embodiments of this disclosure can be combined in various ways.

[0237] Unless otherwise expressly stated, all terms used in this specification and claims shall be interpreted as "non-limiting". For example, terms such as "comprising", "having", "possessing", and "having" shall be interpreted as "not excluding the presence of constituent elements other than those described". Furthermore, the modifier "a" shall be interpreted as "at least one" or "one or more". In addition, the phrase "at least one of A, B, and C" shall be interpreted as "A", "B", "C", "A+B", "A+C", "B+C", or "A+B+C". Moreover, it shall be interpreted to also include combinations of these elements with constituent elements other than "A", "B", and "C".

Claims

1. A laser system, wherein, The laser system includes: A pump laser device that outputs pump light of a first wavelength; A signal laser device that outputs signal light of a second wavelength that is longer than the first wavelength; An optical parametric crystal that allows the pump light and the signal light to pass through and outputs amplified light of the second wavelength; A photon flux density control mechanism controls the photon flux density of the pump light and the signal light, and adjusts the sum of the photon flux densities of the pump light and the signal light at the input end of the optical parametric crystal, so that the intensity distribution of the amplified light of the second wavelength becomes a monotonically decreasing intensity distribution from the center outward.

2. The laser system according to claim 1, wherein, The photon flux density control mechanism includes: A first focusing optical system adjusts the beam diameter of the signal light; A second focusing optical system adjusts the beam diameter of the pump light; A first power controller adjusts the power of the signal light; and A second power controller adjusts the power of the pump light.

3. The laser system according to claim 2, wherein, The first and second condensing optical systems each include a lens pair configured to adjust the distance between the lenses. The first power controller and the second power controller each include a λ / 2 plate and a polarization beam splitter, configured to adjust the rotation angle of the λ / 2 plate centered on the optical axis.

4. The laser system according to claim 1, wherein, The intensity distribution of the pump light and the signal light is Gaussian.

5. The laser system according to claim 1, wherein, Controlling the photon flux density of the pump light and the signal light includes controlling the photon flux density of the pump light and the signal light such that the sum of the photon flux densities of the pump light and the signal light satisfies the conditions determined by the optical parametric crystal, the pump light, the signal light, and the idler light.

6. The laser system according to claim 5, wherein, The conditions are determined by the following factors: The crystal length of the optical parametric crystal; The effective nonlinear constant of the optical parametric crystal; The refractive index of the optical parametric crystal at the wavelengths of the pump light, the signal light, and the idler light, respectively; The angular frequencies of the pump light, the signal light, and the idler light; The beam intensity of each of the pump light, the signal light, and the idler light at the beam center within the optical parametric crystal.

7. The laser system according to claim 1, wherein, The photon flux density of the pump light and the signal light satisfies the following equation: [Number 1] Here, the subscripts s, i, and p represent signal light, idler light, and pump light, respectively. [Number 2] C: Speed ​​of light ε0: Dielectric constant of vacuum Planck's constant / 2π ω s ω i ω p Angular frequency of each light source j s j p Photon flux density of each light source d eff Effective nonlinear constant of a nonlinear optical crystal L: Crystal length of the nonlinear optical crystal n s n i n p The refractive index of a nonlinear optical crystal at various wavelengths. K: The first type of complete elliptic integral.

8. The laser system according to claim 1, wherein, The pumped laser device includes a first semiconductor laser, a first solid-state amplifier, and a first nonlinear optical crystal.

9. The laser system according to claim 1, wherein, The signal laser device includes a second semiconductor laser and a second solid-state amplifier.

10. The laser system according to claim 1, wherein, The laser system also includes a wavelength conversion system that performs wavelength conversion on the amplified light of the second wavelength output from the optical parametric crystal.

11. The laser system according to claim 10, wherein, The wavelength conversion system outputs sum-frequency light by incident amplified light of the second wavelength and ultraviolet light from the optical parametric crystal.

12. The laser system according to claim 10, wherein, The wavelength conversion system includes a second nonlinear optical crystal, a third nonlinear optical crystal, and a fourth nonlinear optical crystal arranged in series.

13. A laser processing method, wherein, The laser processing method includes the following steps: A laser system is used to generate a second wavelength of laser light, and the second wavelength of laser light is converted to generate ultraviolet laser light; and The laser that irradiates the object with the ultraviolet light is used to process the object. The laser system includes: A pump laser device that outputs pump light of a first wavelength; A signal laser device that outputs signal light of a second wavelength that is longer than the first wavelength; An optical parametric crystal that allows the pump light and the signal light to pass through and outputs amplified light of the second wavelength; and A photon flux density control mechanism controls the photon flux density of the pump light and the signal light, and adjusts the sum of the photon flux densities of the pump light and the signal light at the input end of the optical parametric crystal, so that the intensity distribution of the amplified light of the second wavelength becomes a monotonically decreasing intensity distribution from the center outward.

14. The laser processing method according to claim 13, wherein, The photon flux density control mechanism includes: A first focusing optical system adjusts the beam diameter of the signal light; A second focusing optical system adjusts the beam diameter of the pump light; A first power controller adjusts the power of the signal light; and A second power controller adjusts the power of the pump light.

15. The laser processing method according to claim 14, wherein, The first and second condensing optical systems each include a lens pair configured to adjust the distance between the lenses. The first power controller and the second power controller each include a λ / 2 plate and a polarization beam splitter, configured to adjust the rotation angle of the λ / 2 plate centered on the optical axis.

16. The laser processing method according to claim 14, wherein, Controlling the photon flux density of the pump light and the signal light includes controlling the photon flux density of the pump light and the signal light such that the sum of the photon flux densities of the pump light and the signal light satisfies the conditions determined by the optical parametric crystal, the pump light, the signal light, and the idler light.

17. The laser processing method according to claim 16, wherein, The conditions are determined by the following factors: The crystal length of the optical parametric crystal; The effective nonlinear constant of the optical parametric crystal; The refractive index of the optical parametric crystal at the wavelengths of the pump light, the signal light, and the idler light, respectively; The angular frequencies of the pump light, the signal light, and the idler light; The beam intensity of each of the pump light, the signal light, and the idler light at the beam center within the optical parametric crystal.

18. The laser processing method according to claim 16, wherein, The photon flux density of the pump light and the signal light is controlled to satisfy the following equation: [Number 3] Here, the subscripts s, i, and p represent signal light, idler light, and pump light, respectively. [Number 4] C: Speed ​​of light ε0: Dielectric constant of vacuum Planck's constant / 2π ω s ω i ω p Angular frequency of each light source j s j p Photon flux density of each light source d eff Effective nonlinear constant of a nonlinear optical crystal L: Crystal length of the nonlinear optical crystal n s n i n p The refractive index of a nonlinear optical crystal at various wavelengths. K: The first type of complete elliptic integral.

19. A method for manufacturing an intermediary layer, wherein, The manufacturing method of the intermediary layer includes the following steps: A laser system generates a second wavelength of laser light, which is then converted to produce an ultraviolet laser. This ultraviolet laser light is then applied to an object to create an intermediate layer. The laser system includes: A pump laser device that outputs pump light of a first wavelength; A signal laser device that outputs signal light of a second wavelength that is longer than the first wavelength; An optical parametric crystal that allows the pump light and the signal light to pass through and outputs amplified light of the second wavelength; A photon flux density control mechanism controls the photon flux density of the pump light and the signal light, and adjusts the sum of the photon flux densities of the pump light and the signal light at the input end of the optical parametric crystal, so that the intensity distribution of the amplified light of the second wavelength becomes a monotonically decreasing intensity distribution from the center outward.

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